## Near Light Speed Drive

NASA Ion Drive

### Sometimes It’s The Little Things

I was reading a very interesting book (about the “Electric Universe”, more on that in another posting after I ponder it a bit more…) and in the first chapter or two there was one of those “little things” that makes you think…

They were making a point about folks getting sloppy in science ( in cosmology in particular ) and pointed out that many folks treated Mass and Matter as interchangeable, when they are not. Mass is a property of matter, but mass can change (for example with speed). And they pointed out that in E=MC^2 the M is Mass not Matter, yet folks often talk about turning matter into energy in a nuclear reaction.

### The Trouble with S.O.L.

When you try to go the Speed Of Light ( C in the above equation ), you have a hard wall in front of you. As you approach the S.O.L. you gain mass. This means it takes ever more energy to make the next small increment of acceleration to higher speeds, eventually becoming infinite at the S.O.L. point. Bummer.

The common wisdom (the “consensus” if you will) is that this prevents travel at near the speed of light, since any energy source you would use is of limited capacity and will run out of power before you could even get close to the speed of light.

### Smith’s Infinite Power Drive

But what that Little Thing pointed out to me was that as you approach C, an onboard nuclear reactor will be continuing to convert MASS to energy in proportion to your increased ship mass. Each atom in the reactor is increasing in MASS in proportion to the ship mass. So a nuclear powered ship will have available energy that is also approaching infinity, and in direct proportion to the ships mass.

Basically, a nuclear powered space ship ought to retain the same proportional thrust and acceleration at all fractions of C since the mass of the ship and the mass of the fuel turned to power retain their respective ratios.

If this power is used to produce thrust via something like an ion drive, the ions being shot out the back will also have a very high rest mass in the drive. This means that the force applied to them to accelerate them to ejection speed will also increase in proportion to speed. You will not need a vast store of matter to eject for the next increment of speed, just the same small number of ions as at any other speed. As you approach C, the reaction mass is also approaching infinity (but again, in proportion to the ship mass).

### Conclusion

So I’m left looking at this and thinking that this explains what would really happen and why the folks on board would not notice anything odd about their ship as they approach the speed of light. The nuclear reactor, ion drive, everything; they all will appear normal and unchanged. And if you were accelerating at 1/100 G from the rest frame, you ought to continue to accelerate at 1/100 G as you approach the speed of light.

The implication is that a Near Speed of Light spaceship is possible.

(Just don’t hit anything while going that fast ;-) One speck of dust could ruin your whole day…)

Oh, and it might need a bit of engineering too … I’m hoping that the ability of copper to carry power is a function of mass, and not number of atoms, as you approach C. Otherwise there will be a tiny problem of getting your near infinite nuclear power to the ion drive 8-}

And nobody gets to call the “Near Light Speed Drive” the “Near-LSD” either, OK?

See what happens when I take a day off to read something new….

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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### 87 Responses to Near Light Speed Drive

1. vjones says:

Take another day off and do some more reading. I like the way your brain works.

2. E.M.Smith says:

A quick little spread sheet calculation shows that at 1/100 G it would still take 105.7 years to reach C so we’re going to need a 1/10 G ion engine to make it in 10.57 years…

Something more like the magnetoplasmadynamic engine:

as the one in the picture up top is only a 1/1000 G drive and I don’t think we’re gonna like running it for 1057 years just to get up to speed…

Wonder how much reaction mass that MPD engine is going to eat in a decade… Probably going to need a Bussard Collector:

http://memory-alpha.org/wiki/Bussard_collector

3. Heber Rizzo says:

As our old teachers in Uruguay used to summarize our qualifications:

Good effort! Keep working, you can do better still!

4. Wes says:

Chief,

The speed of light is only a local speed limit. We routinely observe the light from galaxies that are receding from us at velocities greater than the speed of light, in some cases much greater than the speed of light.

All galaxies with redshift greater than about z=1.5 are receding at faster than light speeds. We see them out beyond z=5.

As for your example above, the mass of the spaceship has increased, but only with respect to the observer (who now looks quite massive to you) you left behind.

You are right that the folks on board won’t notice anything unusual.

5. Roger Sowell says:

The link below is much closer to the way I remember the physics of light speed. No such thing as galaxies receding at speeds greater than the speed of light. Even if that were possible, the light from said galaxies would never reach us, thus becoming invisible.

http://www.universetoday.com/2008/04/22/how-can-galaxies-recede-faster-than-the-speed-of-light/

6. Ken McMurtrie says:

Am I right in saying that photons, constituents of light have a small mass.
This is proven by impinging light causing rotation of a small “windmill” with a reflective vane in a vaccuum.
Also this mass is the reason that gravity bends a light beam.
How does this fit in with your theory?
In fact, how does it reconcile with E=MC^2?

7. H.R. says:

@ Roger Sowell
“The link below is much closer to the way I remember the physics of light speed. No such thing as galaxies receding at speeds greater than the speed of light. Even if that were possible, the light from said galaxies would never reach us, thus becoming invisible.”

My brother probably solved that problem years ago. His hypothesis was that if he could see clearly for X distance and I could clearly for about the same distance X, then if we combined our efforts, we should be able to see clearly for a distance of 2X.

(You need proof? We used to travel at high speeds in his ’72 240-Z with both of us keeping our eyes peeled for the authorities. We never got a ticket because we always spotted any cops before they saw us.)

To see galaxies receding at speeds greater than the speed of light is just a matter of having a sufficient number of observers ;o)

That, or buy a faster telescope.

8. TGSG says:

(Just don’t hit anything while going that fast ;-) One speck of dust could ruin your whole day…)

From what I’ve read, even something as small as an atom of hydrogen, when you’re traveling that fast, would pack one heck of a whallop.

9. Wes says:

@Roger Sowell

Superluminal expansion of the universe certainly occurs. We can observe galaxies that have, and always have had, recession velocities (relative to us) greater than the speed of light.

And, no laws of physics are violated in the process.

This should explain it :

http://www.publish.csiro.au/?act=view_file&file_id=AS03040.pdf

10. Mike Bryant says:

“And when we break light speed, a mighty bloom of light will herald the masters of time.”
–Magister Lumi :)

11. Roger Sowell says:

Wes, I’ll go with Stephen Hawking on this one. No galaxies are going faster than light speed. Period.

The article you cited postulates faster-than-light galaxies, emitting photons back in “our direction” that are eventually caught up by the ever-expanding Hubble Sphere.

All well and good, if such light photons were ever emitted. But they cannot be, as Einstein proved and Hawking agreed with.

For any object to move at the speed of light requires an infinite amount of energy; for an entire galaxy to move at faster-than-light speed, well, one staggers to imagine the energy required, and from whence is (or was) it obtained?

12. Ken McMurtrie says:

Correction to my earlier comment:
Re photons – have energy and momentum, but apparently no mass. Excuse me for being confused.

13. P.G. Sharrow says:

The NASA Ion Thruster is a cute toy but has no real use as a space drive. It is still a reaction engine and needs mass to waste to create propulsion. A real space drive uses EMF manipulation of space to accelerate its self.
“There is not nothing in space.” Space is packed solid, full of something that carries EMF ( Electro Motive Force) effects.

Space is a very large area, a long way between pit stops.:-( and you have to carry every thing you might need with you, there and BACK. No reaction engine will work as a truespace drive.

I studied to be a rocket scientist back in the late 1950s and my study of all forms of reaction engines from black powder to atomic bombs yielded the same answer, reaction engines were ok for local jaunts but no real space travel.
Gave it up, studied electricity and electronics, became a farmer.

Then someone turned me on to UFOs and I realized I was looking at EMF devices, (form follows function) and reported effects were EMF effects.

What was needed was reverse engineering, :-) my kind of thing. Over 100 years of experiments with electricity have indicated hints that might yield a truespace drive, just need to fit all the clues together.

Modern physics has many errors in facts and understanding. E= MC^ is one of many, “M”= mass, not matter, “C^”- speed of light squared is a very large number that is close enough but also very wrong in concept. The formula was created to explain the lose of mass in a nuclear event when a neutron is changed back to a hydrogen atom. The hydrogen has less mass/inertia (energy) and the energy is liberated.

The creation of a theory of physics that incorporates all that is presently known and drops the BS ( Bad Science) that has been added over the last 100 years has been a 20 year project.
Climate science learned a lot from physics science on how to scam the system.
If you wish I can explain PGs point of view, be careful for what you wish.
I am presently working on a device to test the manipulation of the Aether to confuse mass/inertia and gravity. ( ChiefIO you have my address and permission to contact me pg.)

14. E.M.Smith says:

Well, this seems to have kicked off a bit of a ruckus!

@PG: I might just drop you a line. In reading about the electric universe those guys are of the opinion that gravity is an electrical artifact and that the sun is not fusion powered. To the extent they ‘have something’ it opens interesting options. If not, it’s still an interesting thought experiment.

One thing that has always bothered me, they happen to solve.

Why does the sun not explode?

We’ve made fusion reactions ‘go’. They blow up….

If you make them bigger, they blow up more.

I just don’t see where you ever can get enough gravity from mass to overcome the excess energy from fusing that same mass…

I always figured it was just me not knowing enough of some fancy math / physics “trick”. Now I’m not so sure…

Basically, if the gravity is sufficient to keep the fusion going, it ought to be able to keep the coronal gasses at home too. And if it’s not able to keep a thin gas in place, how can it contain a thermonuclear reaction with all that implies….

So the whole self regulating stable thermonuclear reaction thing is just a bit dodgy on the details… And if it isn’t nuclear, then what is it?

Strange universe we live in…

And yeah the system needs reaction mass. Thus the Bussard Collector line. (How to collect H2 at C and not suddenly glow brightly in the dark sky is left as an exercise for the Engineers…)

@Ken McMurtrie: I don’t see where light photons change anything about a nuclear reactor and plasma jets. They are wave/particle systems with some of each, so will have their own set of rules. The things with turning vanes in a glass bulb have been shown to NOT be due to light momentum, but rather differential warming and the small residue of air in the “vacuum” that heats on the black surface and imparts momentum to it. (It’s the air, not the photons). And as I understand it, the light is not bent by gravity, space itself is bent. The light is taking a straight line as far as it knows…

@All:

I can see the argument that says the galaxy some long ways away is moving at above C since it is SPACE that is expanding, not the object moving locally. Don’t like it though ;-)

So at no time is any object moving faster than C, yet 2 of them are moving away from each other faster than that due to the space itself expanding…

But it just sounds wrong….

15. NZ Willy says:

Please, *mass* and *weight* is what confuses people.

16. Ken McMurtrie says:

Hi EM.
Regards the energy of the photon, recently I read about a spaceship design using solar energy applying a force on a large “sail”. Maybe it wasn’t just photons. It may have been cosmic radiation or??. I’ll try to find the reference. Besides, scientific explanations of photons mention kinetic energy.
My initial reference to photons came from the perhaps erroneous theory that the photon possessed a minute mass, making it, according to E=MC^2, “ineligible” to travel at c. It is puzzling, to me, that the photon can possess kinetic energy when it supposedly has no mass. Quantum theory is out of my league, but i just like things to make some sort of sense in concept.
Regards bending of light, although curvature of space is an accepted theory, it begs the question of what element of space is there to be bent. There is not supposed to be an ether or any such property, is there? If some undetectable field exists independently of mass in the universe and it is distorted by the presence of a mass, then the photon still must have some property which iinteracts and follows the “field” lines.
Sorry to bore you with my primary level science theories. It is therapeutic to air my views.
Regards.

17. Wes

@Roger Sowell

“Superluminal expansion of the universe certainly occurs. We can observe galaxies that have, and always have had, recession velocities (relative to us) greater than the speed of light.”

That hypothesis (which posits redshift as an indicator) was falsified long ago. Your expansion of the universe presumably relies on expansion of spacetime, which you think is evidenced by redshift. However, there is so much evidence against such an explanation, that we can confidently say this has been falsified. I cannot see Big Bang cosmology surviving much longer now that we have so many excellent instruments feeding us data that falsifies it.

18. P.G. Sharrow says:

Welcome to my world. The standard theory has more holes in it then a swiss cheese. Many of the known facts don’t fit in it. Accepted constants aren’t. And all this crap is taught as gospel fact.
Many of the commentors above have a better grasp of reality then the people that teach the subject.
Back in the 1920s the fields of astro physics and matter physics took a hard left turn, disgarded accepted explainations and ran off following shinny new theories, many of them wrong. Kind of like climate science.
The fields of electrical and electronics effects were built around the existence of aether. the failure of the worlds foremost expert in light to prove the existence of aether was cited as proof of its none existence. ( in my opinion a poorly laid out experiment) later experiments by others seem to demonstrate the existence of aether but these have been ignored. To have lines of force magnetic fields in space there needs to be a magnitizeable carrier, to have any EMF effects in space there needs to be a carrier, aether.
Aether; dark matter, dark force, fabric of space, even the soul of GOD, what ever you want to call it, needs to exist for every thing to work.

Ranting, foaming at mouth, must get down off of soap box.

19. Don’t complicate it with nuclear power, electric drive and ions. The argument you make can be made just as well (better, in fact) by considering a rocket with chemical propellant that we all know about – the only downside is the limited amount of energy available for a given mass with known propellants – so simply IMAGINE a better one for the sake of a thought experiment.

As Wes pointed out, you only appear more and more massive as you accelerate when measured against someone else’s rest frame. For you on board, in your own inertial frame, you don’t appear to be getting any more massive, and your acceleration can be set so that you will continue to accelerate at a constant rate ad infinitum (limited only by your fuel supply). You could have an accelerometer on board as a record of constant acceleration, and a clock as well. By calculating velocity = acceleration x time you would think you should be travelling at well over the speed of light. But as you look back to earth, you will not appear to be going as fast against that reference as you would expect from consulting your accelerometer and knowing the time elapsed. That’s because of the time dilation effect etc. As far as you are concerned, you are just going faster and faster, but strangely, when you look back, you only seem to be receding from earth at approaching the speed of light, never faster.

20. @ P.G. Sharrow. Although I agree with much of what you say and I’ve been complaining about and challenging fraudulent ‘settled science’ for decades, I can’t easily accept this: “To have lines of force magnetic fields in space there needs to be a magnitizeable carrier, to have any EMF effects in space there needs to be a carrier, aether.”

I have been working in electromagnetics for 30 years, and I really can’t see that is the case. I will agree with you that there are serious objections relating to the Michelson-Morley experiment (which I have actually performed at University of Oxford in 1978/9), but the inability to rule out an aether still doesn’t mean that there is one. I do find Maxwell’s equations work rather beautifully without the need for any aether, and the speed of light in vacuo is simply related to permittivity and permeability of a vacuum. Because vacuum has permeability and permittivity doesn’t lead me to think it must contain a carrier substance. As far as I can see, vacuum (empty space, but having dimensions) is a perfectly good aether, if you want to identify such a concept.

21. P.G. Sharrow says:

@ scientistForTruth
you might find this blog entry of interest. pg

22. Tim Clark says:

I can see the argument that says the galaxy some long ways away is moving at above C since it is SPACE that is expanding, not the object moving locally. Don’t like it though ;-)

So, if you’re in a spaceship traveling 10 km/hr less that the speed of light, and you turn on a flashlight and shine it through the thick plexiglass windshield, what happens?

23. @Tim Clark “So, if you’re in a spaceship traveling 10 km/hr less that the speed of light, and you turn on a flashlight and shine it through the thick plexiglass windshield, what happens?”

10km/hr less than the speed of light compared to what?

For you in the spaceship, when you switch on the flashlight, the light will recede from you at the speed of light.

If you appear to be going at 10km less than the speed of light to an external observer and you switch the flashlight on, then the light from the flashlight will appear to the external observer to be travelling at the speed of light as well. However, it will be shifted in frequency compared to what you see.

From your vantage point, the difference between your velocity and the light from the flashlight is the speed of light.

From the external observer’s viewpoint, the difference in speed is 10km/hr.

Why the difference? Because of time and other dilation effects. Things going on in your reference frame don’t appear dilated to you, but things going on in your reference frame appear highly dilated to the external observer.

24. @P.G. Sharrow “you might find this blog entry of interest”. I think there are different concepts being mixed up here: a medium that happens to be there, and the necessity for a medium.

To the question: is there something pervading space that can affect light compared to its behaviour in vacuo? Is there relative motion between us and this ‘something’? I answer: possibly. And this might be the source of redshifting and other measurable phenomena.

But to the question: is it possible to transmit electromagnetic radiation in a true and perfect vacuum devoid of this ‘something’? I answer: certainly. There is no medium necessary for the transmission of electromagnetic waves other than empty space, that is, three dimensions containing nothing whatsoever. Some will say that even a perfect vacuum has quantum fluctuation – but that is a complete red herring as far as this matter is concerned.

25. BillN says:

In the post you state:

“… onboard nuclear reactor will be continuing to convert MASS to energy in proportion to your increased ship mass…”

I have not read the book you referenced, but it is my understanding that the energy from a nuclear rector is based on the mass defect from either the fusion of light nuclei or fission of heavy nuclei. This “mass defect” term is misleading but it is NOT a measure of the mass being “used up” in the nuclear reactor. An extended explanation is given below for others who may be interested but don’t have the background.

The mass defect is characterized by the binding energy per nucleon curve (be/z); e.g., see:

http://en.wikipedia.org/wiki/Nuclear_binding_energy

The x-axis represents the number of nucleons in the atomic nuclei under consideration.

Fusion reactions move from the extreme left of the curve with two low mass number atoms with low be/z to a new, higher mass number nucleus at a higher be/z. Fission reactions move from the far right with a heavy mass number nucleus split into two lower mass number nuclei, both at a higher be/z than the initial nucleus. The total number of nucleons before and after the reaction is the same. [yes, some subsequent b- decay, etc, will occur but not cogent to discussion] For both reactions, moving to a higher be/z point means the end-product nucleus/nuclei are more tightly bound compared to the initial nuclei/nucleus.

The extra energy that had been needed to hold the initial nuclei together (because the initial nuclear structure had a lower be/z) is released. The “mass defect” is the apparent difference in mass between the initial and final nucleons and is proportional to the amount of energy released (proportionality constant is c^2).

What this means is that a nuclear reactor’s power is not based on the mass of the reactor but rather the structure of the atom. So, while relativistic mass is increasing as approach the speed of light, the properties of the atomic structure will be constant under the nuclear reactor’s reference frame. Thus, the be/z properties do not change.

Thus, no infinite energy source.

- Bill

26. P.G. Sharrow says:

Waves traveling in nothing.

bs…………………pg

27. E.M.Smith says:

@BillN:

I was not asserting that the mass of the reactor structure mattered, but that the increased mass of the reacting ATOMS mattered as that ought to make the “mass defect” larger in proportion to the mass of the nucleons. Same percent, different absolute value.

You could make the case that the mass defect as a percent of total mass will decrease as the masses of the reacting atoms increase, but I see no reason to leap to that conclusion. I’d have to see some accelerator data to support that position before I’d embrace it.

Also note: At no time have I said this would enable FASTER than light travel, only that it would allow you to get to ‘near light’ speed as the approach to near infinite mass would be matched by a proportionate energy release from the near infinite mass of the fissioning (or fusioning) nuclei (and the attendant near infinite mass defect). Basically, it explains how the folks on the ship could see a world where they just keep accelerating at a constant rate. (And says nothing about how they would perceive time dilation – I would expect a Near Light Speed Drive to be good for ‘one way trips’ through time gong forward. That is, you could get to a star 30 light years away, and back, but everyone you knew here would be way old… while for you, far less time would have passed. Standard relativity stuff). The only real insight was that the ‘near infinite mass’ of the ship does not need power that is unavailable to accelerate it. It only needs the same power that was moving it to begin with, but also scaling with the relativity increased mass.

28. Ken McMurtrie says:

I know I am relatively (some may say completely), ignorant in space science (not to mention many other areas) but it seems to me we have bit to go before even the scientists come to some, (sorry), consensus. (I like to think that I can think with some degree of logic).
If space can expand, surely it must have some properties – what are they? I think this expansion idea needs a better basis than that it explains some apparent observations.
“ScientistforTruth” suggests that space has properties of permittivity and permeability, difficult to understand how “nothing” can have properties.
As for propagation of waves, it is not impossible to visualise electromagnetic energy waves flowing through truly empty space. Similarly magnetic fields existing in an empty space. Likewise, what we imagine to be a gravitation field, acting on all masses. Such a gravition field could have the “aether” properties we are looking for.
Presume we have got away from gravity waves created by the masses themselves.
Light has a slightly different form, whereby kinetic energy hints at something more than a wave of energy.
Yet their propagation velocities are seemingly, similarly limited to “c” in vaccuum. Is the limit due to some inherent characteristic of “space”, or due to the wave itself having an inherent physical restraint
To me, all these weird theories like space expanding, time dilation, are resulting from some part of the existing theories of relativity being actually wrong or incomplete, or our inability to measure the speed of light independently from our own environment, or both.
Being a mere mortal in an relatively infinite universe, where even our planet is alike to a grain of sand in a vast desert, is a wonderful experience.

29. crosspatch says:

“I was not asserting that the mass of the reactor structure mattered, but that the increased mass of the reacting ATOMS mattered as that ought to make the “mass defect” larger in proportion to the mass of the nucleons.”

Relative to what? As you approach C from someone on Earth’s perspective, you might be seen as decelerating from the perspective of someone on a galaxy moving away from Earth at near light speed as your regression from them slows. And if you are on the ship, light still seems to travel at the same speed it always did. You can get to 1/2C and if you turn on your flashlight in the direction of travel, the photons will still seem to move away from you at the speed of light.

So from some perspectives you might look like you are accelerating, from others you might appear to be decelerating, and from your own perspective, light hasn’t changed at all and all you notice is a gravitational force from your acceleration.

So the mass is not changed from your perspective. It has increased from the perspective of someone on Earth but it has decreased from the perspective of someone else who you are now no longer receding from.

So has the mass really increased at all or are you just comparing it from a now obsolete frame of reference? You can never travel faster than the speed of light because time changes. Even if you are at 99% of the speed of light (relative to someone on Earth), the light from your flashlight will still seem to go away from you at the same speed it was when you were on Earth. But your “second” will be different. When you reach the speed of light, all of eternity is but a blink of an eye … from the perspective of where you left yet time will seem to be moving normally for you and from that galaxy that was receding from you at near the speed of light, you are stationary, you have stopped.

So whose “speed of light” is the limit? The point where you started? Or could you then accelerate toward that previously receding galaxy? And if so, would “space” begin to expand between you and Earth in order to explain why you are now going faster than light speed relative to them?

30. E.M.Smith says:

@Ken McMurtrie:

The dual nature of photons explains a lot. They are both waves and particles. So as they oscillate between partial embrace of each side of their dual nature, you get things like a massless wave that still has momentum. The “Solar Sail” works by having a photon absorbed, then reemitted as a wave going away from the sail, and putting the ‘delta v’ into the sail. So it is massless in transit, but has imparted energy of motion to the object that absorbed it and then reemitted it.

At the very small scale of quantum effects, all sorts of ‘rational’ expectations break down. I don’t pretend to really understand it, just admire some of the odd bits. So you can have an experiment where a single photon goes through a grid. It can only pass through one slit, yet you get an interference pattern on the other side. There are a load of these ‘odd things’ and standard physics has cooked up an ever increasing set of ‘odd rules’ so they can be described.

One of my favorites is the P orbital of an atom. In theory, the probability of an electron being in any particular place makes a bowtie shaped sausage poking out each side of the nucleus. The Probability drops to exactly ZERO at the mid-line of the bowtie (in the center of the nucleus and extending to infinity in all radial directions in that plane. Yet the electron can be on either side of the nucleus at any time. Without ever having been in the middle…

It’s that kind of stuff that lead to the admonishment that if quantum mechanics started to confuse you “just shut up and calculate”…

Basically, the universe of the quantum particle is so divorced from where we live that our conceptions of reality are very broken at that scale.

(And no, I don’t know if it is true, just that is what is taught.)

There have been some truly bizarre experiments done that tend to confirm the off the wall nature of quanta…

(One thesis for the ‘not in the middle’ issue with electrons is that they exist in other dimensions, so at the moment where they cross the mid-line, they transition to those other dimensions, then return to ours on the other side. No, I have no idea if there is merit to that idea. Just heard it being pushed once…)

Per Aether:

Don’t know if it’s there, don’t know if it isn’t. I am pretty sure that ‘empty space’ has a lot of ‘stuff’ in it (even if some of it is electromagnetic waves). And those are the same EM waves that make up a photon… So if a photon can travel through ‘empty’ space, then any other frequency of photon ought to as well… and I see nothing that requires a ‘medium’ for a particle to pass through space. And photons have that dual particle and wave nature… (Gravity I have no clue about. I’ve seen folks who claim it travels at the speed of light, and others who say it must act instantaneously for orbital mechanics to work right. So I don’t know what makes it, nor how it propagates. Nor, I think, does anyone else really… The Electric Universe folks seem to think it’s a minor leakage from an imbalanced electrostatic force. But since it decays as the inverse square and electrostatics decay as the inverse simple, I don’t see how they can be the same root cause… Then again, I may just not know enough about what is known about gravity ;-)

And per ‘nothing’ having properties: Is the volume inside a sphere possessed of size in each direction? Even if an empty space? Does it have a volume? If you flattened the sphere into an ellipse would those not change? yet it is the sphere that has physicality… So yes, ‘empty’ things can still have properties. Measure the capacitance and impedance of two metal plates with a bit of plastic between them. Then with air. Then with the air pumped down to a hard vacuum. Does not that ‘empty space’ have a breakdown voltage? A dielectric constant? Yes, you can ‘measure nothing’…

Or, looked at another way, the limit of C in a vacuum is one thing, but then a photon slows down as it must work it’s way through other ‘stuff’, so the vacuum speed is just the inherent speed of the photon and the other stuff brings the ‘slowdown’ part. You can still measure both, but this makes it clear that the difference is not due to the vacuum, but to the ‘something’ like glass that the light must pass through when not in a vacuum.

The world of subatomic physics is a strange and wondrous place and one I only dimly comprehend. But what is very clear is that it has little in common with the world scale in which we live.

31. E.M.Smith says:

@Crosspatch:

I suspect we are in violent agreement ;-)

I say AGAIN: I have never asserted this would let you go faster than light.

I have said it is a way to see why the folks on the ship see no change yet the folks outside see the ship going near light speed.

From the perspective of a stationary observer, you appear to approach infinite mass, but also have near infinite power pushing you faster. From the perspective on board, everything is as it was when starting from rest, including both mass and power, except you are traveling ever faster (and as time dilation slows you down, things outside look to be moving even faster…)

So if you were to use a nuclear reactor to kick reaction mass out the back,you will, from your perspective, proceed at (roughly) constant acceleration toward (but never reaching) the speed of light. DESPITE the apparent near infinite mass of your ship as seen from a stationary observer (since from their perspective you are also running a very high energy reactor converting very large mass to energy).

So from your perspective, nothing changes. You do not experience the ‘infinite mass’ problem nor do you need ‘infinite energy’ to overcome it. From the stationary observers point of view (from which the mass change is usually described…) they see you gaining mass and say “Oh My Mr. Bill, they need near infinite energy!” “But look, they are getting it from those very very heavy atoms they are reacting”…

Since I’m interested in what happens inside the ship, the idea that I can just keep accelerating and not worry about the near infinite mass problem is a Very Big Feature.

Or put as directly as I can figure out how to put it:

The “infinite mass” problem is a stationary observer issue and they would also see large energy production. It is not an issue from the point of view of an observer on the ship and they see both normal energy production AND normal acceleration even as they approach C.

32. Ken McMurtrie says:

I think that suggesting that nothing can have the property of dimensions if it is enclosed is missing the point. Re as a dielectric, the “nothing” does not contributing anything, the gap is due to the mounting of the plates, the electric properties then belong to the plates and their gap, not the nothing that occupies the gap. Weird??
Agree that I shouldn’t have to understand the Quantum world, for obvious reasons, BUT if our interpretations and theories create paradoxes which don’t make sense, then we shouldn’t feel comfortable with our theories.
Yes, I am also saying that anything could pass through empty space, without the need for a “medium”. Sound wont because its very existence relies on a medium of molecules.
I am pleased that you agree that much is still unkown. My point, starting from that premise, is that none of us should get seriously hooked on scientific theories unless there is an absolute verifiable proof. All questions must be satisfactorily answered, or an open mind is advised.

BTW, On AGW, if you forgive the topic change, have you noticed the interesting revelations about NASA in this site?
http://climaterealists.com/index.php?id=5783

33. The fact is, a vacuum is not ‘nothing’. Just because it is devoid of mass and particles doesn’t mean it is ‘nothing’. It has dimensions, location. Time and the laws of physics apply therein.

And, yes, just as a vacuum has dimensions, so it has a permeability and a permittivity. Why should that be thought so strange? If it has properties of space, why shouldn’t it have other properties? Space isn’t ‘nothing’.

As for the suggestion that waves passing through a vacuum is BS, can I please suggest you read up on your electromagnetism. Nobody is suggesting that waves pass through ‘nothing’. Spacetime isn’t ‘nothing’. The only ‘medium’ you need to propagate EM radiation is space itself. Come now, we’ve moved on a bit since Aristotelian physics.

What medium does a bullet need to travel in? None but empty space: space and time. Why does it continue on at a constant velocity forever in a vacuum (unless acted upon by an external force)? Because it has momentum. All EM radiation is composed of photons, and every photon has momentum. There is also the wave-particle duality. One doesn’t need an elastic medium for these waves because they are comprised of oscillating, travelling, electric and magnetic fields. For these, one needs three dimensions (because they are orthogonal) and time. Nothing else.

34. E.M.Smith says:

FWIW, found this site with a long list of articles per experiments that claim to find evidence for the existence of the Aether:

http://www.orgonelab.org/energyinspace.htm

Either an awful lot of folks are making errors that show an aether exists or there is something going on here…

I don’t have the time right now to read them all, but it’s a pretty long list.

35. Ken McMurtrie says:

Hi ScientistforTruth.
Sorry but we have some miscommunication here.

My first relevant reference was “quoting” you as follows:
““ScientistforTruth” suggests that space has properties of permittivity and permeability, difficult to understand how “nothing” can have properties.”

“Yes, I am also saying that anything could pass through empty space, without the need for a “medium”. ”

I do not understand your claim that I said or inferred the following:
“As for the suggestion that waves passing through a vacuum is BS, can I please suggest you read up on your electromagnetism.” etc.

This is not what i said, nor my contention, it is in fact, the opposite. Also, the only time I used the word vaccuum was in connection with the speed of light “c”.

Therefore, your last two paragraphs have no relativity to what I said.

After all that, our beliefs of the likely or possible nature of space are clearly not in agreement.
I have certainly referred to space as “empty nothing” in respect of it acting/or not as a medium for propagation of electro magnetic energy, which includes light.
I accept that space is not empty in that it contains all sorts of real particles and cosmic and EM radiation, and in some way gravitation fields, but these do not constitute space. Except, maybe space is a field of energy in its own right either creating gravity or acting as a medium for gravity.

As I said, I believe that nobody KNOWS enough to be adamant that any currently held beliefs are indisputable. In particular because, as I said, there is no consensus.

36. Hi Ken. I wasn’t referring to you at all but to the earlier comment by P.G. Sharrow which stated “Waves traveling in nothing. bs…………………pg”. I took that as a comment on my earlier comment which referred to EM radiation in vacuo. I did not call vacuum ‘nothing’, but it seems that P.G. Sharrow took me that way, hence my response. He seems to have read my statement that the only medium necessary for propagation of EM radiation is empty space containing nothing, but of course space containing nothing isn’t itself ‘nothing’ – it is something: space.

This so-called aether that some claim to have measured the earth passing through, and which is claimed to affect EM radiation, might exist. I’m open minded on that, as I said earlier. However, to say that because something exists that is perturbing EM radiation proves that such something is necessary for EM radiation to propagate would be a fundamental logical error. There is no medium other than free space required. On the other hand, EM radiation can pass through lots of different media and be affected by such, and it seems to me that this is all that the aether results show, which is something quite different.

37. KevinM says:

Aether experiments:

Do you use tools to observe the medium, or observe tool behavior in (or absent of) a medium?

Is ‘nothing’ possible at all?

Is the permeability of free space a property of free space or of waves?

Pi exists.

38. pyromancer76 says:

OT – From NASA JPL guys – (Spaceweather). Funny as….
http://wiki.nasa.gov/cm/blog/whatonearth/posts/post_1275422073165.html

Lost a post on geology travel. Will recreate when time. Thanks for all the links.

39. Jason Calley says:

Hey E. M.,
You mentioned the Bussard Collector Ram Drive. I am not sure if you are familiar with Bussard’s work on developing a practical fusion reactor. If you are not, by all means, please view his talk at http://video.google.com/videoplay?docid=1996321846673788606#
Absolutely fascinating, and looks practical. As is so often the case, we humans have the technology to solve our problems, we just do not have politically viable ways to implement the solutions.

40. E.M.Smith says:

@pyromancer:

Thanks! That’s a hoot! (And much more interesting than watching markets go nowhere by bouncing up and down fast… running in place as it were… Looked over just about everything and found nothing moving net to speak of over a week or three. So I’m sitting in my Nat Gas high dividend stocks and waiting and waiting and, well, and now laughing!)

@Jason Calley: I’ll take a look!

41. @KevinM “Is the permeability of free space a property of free space or of waves?” Free space. Likewise the permittivity. For material substances, their permeabilities and permittivities are are often stated RELATIVE to their free space values. So polythene has relative permeability of 2.35, and electrical steel has relative permeability of around 4000.

Everyone knows Einstein’s relation E =mc^2, but there is also a very elegant (beautiful?) relation between the speed of light in free space and the permeability and permittivity of free space:

c^2 = 1/[(permeabilty of free space) x (permittivity of free space)]

In other words, you could predict the speed of light by measuring static properties of free space: forces between charged bodies and forces between current-carrying conductors: purely STATIC setups. Check it out for yourselves: working to 4 significant figures

Permittivity of free space is
8.854 x 10^-12 coulombs^2 per metre^2 per newton

Permeability of free space is
1.257 x 10^-6 newtons per amp^2

Since an amp is a coulomb per second, permeability can be expressed in newton-seconds^2 per coulomb^2.

Permeability of free space is
1.257 x 10^-6 newton-seconds^2 per coulomb^2

It is easy to see that by multiplying the permeability and permittivity we end up with

11.13 x 10^-18 seconds^2 per metre^2.

Then

C = 1/SQR [11.13 x 10^-18]

= 2.998 x 10^8 metres per second.

These are the properties of free space. Only linear dimensions and time required.

42. KevinM says:

There is nothing static about current flowing in a conductor.

43. Bruce of Newcastle says:

The Scharnhorst effect is my favourite (Casimir effect causes a negative vacuum, therefore the speed of light in it is faster than c, the speed of light in ‘normal’ vacuum).

OK, here’s a thought experiment: find a way to forbid (in the quantum sense) virtual particle pairs. Then you can get a really serious negative vacuum, in which the speed of light is extremely fast. Add that to your fusion power drive and you can get full bang for the buck without time dilation hobbling you.

Of course if you turned off your negative vacuum you’d explode in a gigantic burst of Cerenkov radiation.

44. P.G. Sharrow says:

on June 2, 2010 at 10:20 pm E.M.Smith on Gravity:

“But since it decays as the inverse square and electrostatics decay as the inverse simple, I don’t see how they can be the same root cause… Then again, I may just not know enough about what is known about gravity ;-)

E.M. you are one hell of a squrrel to spot the nut among the dog turds. :-) thanks pg

45. @ KevinM “There is nothing static about current flowing in a conductor.”

That’s an absolutely trivial point, isn’t it, in the context? The derivation of permeability doesn’t in any way depend on your choice of current, or the velocity of electrons if you want to take it to that level.

What I wrote is true according to universally accepted definitions going back to Michael Faraday: if the current is constant, as it is in the determination of permeability, then there is EVERYTHING static about current flowing in a conductor. That’s down to the definition of magnetostatics. If you wish to define your terms in a different way from how they are defined and used by the scientific community, you are free to do so, but will create endless confusion, and you have no right thereby to deny the use of standard definitions for everyone else.

The derivation of permittivity is by electrostatics, and the derivation of permeability is by magnetostatics. These setups and measurements are defined in physics as STATIC. That’s what the word means: in electrostatics charges are invariant; in magnetostatics currents are invariant.

So, the speed of light in free space can be predicted from static measurements in free space, without ever generating or measuring electromagnetic radiation, or postulating the need for any luminiferous aether.

The speed of light isn’t determined by the property of light, but by the properties of the ‘medium’ in which it travels. In the case of free space, the medium is not a substance or aether, but space having dimensions and time, with permeability and permittivity, which determine how it will behave in those dimensions and time.

To talk about empty space as ‘nothing’, as if to require some aether so that there is ‘something’ is to make a gross error, philosophically and scientifically. ‘Nothing’ would have no dimensions or time, never mind permeability and permittivity. Completely empty space is obviously ‘something’ as it has definable and measurable properties.

46. @ P.G. Sharrow “on June 2, 2010 at 10:20 pm E.M.Smith on Gravity:

“But since it decays as the inverse square and electrostatics decay as the inverse simple, I don’t see how they can be the same root cause… Then again, I may just not know enough about what is known about gravity ;-)

E.M. you are one hell of a squrrel to spot the nut among the dog turds. :-) thanks pg”

Since when? In electrostatics the electrostatic force between two charges is proportional to the product of the charges and the inverse square of the distance (Coulomb’s Law). In gravitation the gravitational force between two masses is proportional to the product of the masses and the inverse square of the distance.

If you are talking about fields, both electric fields due to charges and gravitational fields due to mass drop off with an inverse square law as well.

So where’s the nut, and where are the dog turds?

47. KevinM says:

@ScientistForTruth.

Mr. Coulomb takes out a pen and draws a circle on a piece of paper. He notes that the circumference is proportional to its radius by Pi.

Mr. Oersted walks into the room and tilts the paper vertically and notes that Pi is not constant as the angle you look at the paper changes.

Mr. Ampere Looks at the drawing from the side and agrees, starting a vigorous discussion of how paper angle changes the value of Pi.

They call in Mr. Maxwell who determines that two orthogonal radii are required, and then the circumference of the conic section seen by tilting the circle in any given direction can be calculated with his equation.

Maxwell’s equation confuses everyone with shorthand that buries important trigonometry into the constants H and B, until Mr Smith arrives and designs a reference chart to allow derivation of H and B with a ruler and a number 2 pencil.

Finally KevinM walks into the room and says “Thats all well and good, but there is such a thing as a circle, and its circumference is related to its single radius by Pi.”

ScientistForTruth responds “Don’t be foolish, there can be no circles without paper!”, and demonstrates the accuracy and repeatability of Maxwell’s equation for tilted paper circles.

I chose this analogy because I find your arguments flatly circular.

At least we agree that alternating current in a wire is not static electricity.

48. Tim Clark says:

The world of subatomic physics is a strange and wondrous place and one I only dimly comprehend. But what is very clear is that it has little in common with the world scale in which we live.

I once attended a presentation by a renowned physicist, whose name escapes me now but I think was Michael. There was a Q & A session afterward and, even though I felt stupid, I asked, “What is gravity?” (along with the previous question I asked above). He got into string theory and virtual particles and expanding or contracting universe, etc., etc.
But the jist ( I took notes as fast as I could) of his analysis was that in quantum field theory view, “real particles” are detected because they excite underlying quantum field(s) which are in another dimension, I don’t know, maybe the ninth or tenth ;~P. This dimension is related to or caused by the expansion of the universe and he called it vacuum energy.
So space (or a vacuum) is filled with unexcited particles that we have no ability to measure or “see”. Only when perturbed does it manifest itself. And even though virtual particles have no mass, they do. Go figure.
Well, this undetectable dimension is what we on earth and the milky way, etc. are moving through. Since we have mass, we perturb this vacuum energy which we interpret as gravity. The energy we produce as movement dissipates with distance.

49. @ KevinM “ScientistForTruth responds “Don’t be foolish, there can be no circles without paper!”, and demonstrates the accuracy and repeatability of Maxwell’s equation for tilted paper circles.

I chose this analogy because I find your arguments flatly circular.

At least we agree that alternating current in a wire is not static electricity.”

I’m not sure what you are getting at, and it would be better not to put words in my mouth. And by the way, I never introduced the concept of alternating current in a wire. I was talking about magnetostatics, i.e. constant current.

All this handwaving of yours – why don’t you use a scientific argument and physics? Why don’t you demonstrate where the argument is ‘flatly circular’, if you think it is? Inventing little allegories and skits and making unsubstantiated assertions doesn’t really cut the mustard, I’m afraid. You need to show where things are wrong, inconsistent or illogical, otherwise it’s just mere ranting. If you are going to take exception to standard physics you’ll need to do better than that – and I’d encourage it: I’m happy for anyone to demonstrate a better way in any scientific field: that’s progress, and I’m all for it – and dead against holding on to discredited theories, and suppressing evidence. So, if you have evidence that Maxwell’s equations are wrong, by all means do us all a favour and show us the evidence, and suggest better physical equations. But if you can do neither, a wiser course might be not to meddle with things beyond your ken.

50. Tim Clark says:

By the way, I forgot to give “Michael’s” response to the question I posed earlier. He said the light would travel at the speed of light, relative to the person who turned it on, to the windshield. When exiting the windshield, it would proceed at my hypothetical 10 km/hr. If you were a fly on the surface of the spacecraft, you would actually, visibly see the light advance in front of the spacecraft at 10 km/hr. To someone observing at an undefined distance, but close enough to detect, both the light and the spacecraft would appear to be going the speed of light, as the difference between the velocities of either is minimal. At a telescopic distance, wavelength shift would enable you to discern the advancing light.

51. @Tim Clark “When exiting the windshield, it would proceed at my hypothetical 10 km/hr. If you were a fly on the surface of the spacecraft, you would actually, visibly see the light advance in front of the spacecraft at 10 km/hr.”

No way, absolutely not. What?! – if the spacecraft switched its headlights on, the beam would advance at only 10km/hr from the spacecraft? Don’t make me laugh. The fly, the flashlamp, the windshield and the headlights are in the same inertial reference frame as you are in the spacecraft. All observers see light travelling at the same speed. You, the fly, and the external observer will all see the beam travelling at the speed of light. It would be as I stated earlier:

For you in the spaceship, when you switch on the flashlight, the light will recede from you at the speed of light.

If you appear to an external observer to be going at 10km/hr less than the speed of light and you switch the flashlight on, then the light from the flashlight will also appear to the external observer to be travelling at the speed of light. However, it will be shifted in frequency compared to what you see.

All observers see the light from the flashlight (or the spacecraft headlights) travelling at the speed of light.

From your vantage point in the spacecraft, the difference between your velocity and the light from the flashlight is the speed of light.

From the external observer’s viewpoint, the difference in speed is 10km/hr, as initially defined.

Why the difference? Because of time and other dilation effects. Things going on in your reference frame don’t appear dilated to you, but things going on in your reference frame appear highly dilated to the external observer. And things in his reference frame appear highly dilated to you.

Folks, if this doesn’t make sense, go and read up some relativity. It’s hardly esoteric, and it’s now a hundred years old. This is not, of course, to say that Einstein is the last word on the matter – far from it. But until someone can demonstrate and formulate something better, that’s the best we’ve got, just like Newtonian physics was before Einstein.

52. Janus says:

@ E.M. Smith

“Why does the sun not explode?

We’ve made fusion reactions ‘go’. They blow up….

If you make them bigger, they blow up more.”

“I just don’t see where you ever can get enough gravity from mass to overcome the excess energy from fusing that same mass…

I always figured it was just me not knowing enough of some fancy math / physics “trick”. Now I’m not so sure…

Basically, if the gravity is sufficient to keep the fusion going, it ought to be able to keep the coronal gasses at home too. And if it’s not able to keep a thin gas in place, how can it contain a thermonuclear reaction with all that implies….”

The point you are missing is that not all of the Sun’s mass is undergoing fusion at any time. The sun fuses about 1e11 kg of hydrogen a sec, however the mass of the Sun is 2e30 kg or 2 billion, billion times larger.

It is the weight of all that gas pressing down on the core that allows fusion to take place and contains it and it is the energy of that fusion that inflates the Sun to its size (if the Fusion at the core went out, the Sun would shrink to a much, much smaller size. ) The fusion at the core has to support all the weight of the gas layers above it.

The coronal gases, on the other hand, are at the surface and only has to worry about lifting it own weight. The difference is like between jumping into the air with or without the weight of a car on your back.

As far as your comparison to man-made fusion reactions. In the first place, the Sun uses a different reaction known as the proton-proton reaction which is a lot harder to maintain than the deuterium-tritium reaction used in nuclear weapons. and even then a fission bomb is needed as trigger to start the fusion reaction.

In the second place, controlled fusion reactions have been produced (they don’t all explode), We just haven’t been able to maintain a self sustaining reaction as the energy needed to generate the conditions for controlled fusion still exceeds the energy obtained from it.

“And yeah the system needs reaction mass. Thus the Bussard Collector line. (How to collect H2 at C and not suddenly glow brightly in the dark sky is left as an exercise for the Engineers…)”"

Recent studies have shown that the Bussard ramjet concept doesn’t work as well as originally hoped. A major drawback is that collecting the reaction mass/fuel produces drag on the ship, and eventually that drag equals the thrust you can get from it. Depending on the efficiency of your fusion drive, the top velocity of a ramjet is between 1% and 10% of c. While this is good by today’s standards, it is nowhere near the near light speed velocities dreamed of at first.

53. Tim Clark says:

on June 4, 2010 at 8:39 am ScientistForTruth
@Tim Clark “When exiting the windshield, it would proceed at my hypothetical 10 km/hr. If you were a fly on the surface of the spacecraft, you would actually, visibly see the light advance in front of the spacecraft at 10 km/hr.”

I’m only repeating what his response was. Wish I could remember his name. And lower your voice, please.

54. Janus says:

In response to the idea of Smith’s Infinite Power Drive, The flaw in the idea is fundamental. If someone has already pointed this out, I apologize.

The “increase in mass” as an object increases it’s speed is really just an expression of that object’s kinetic energy. One could say that increasing the energy of an object adds to the object’s inertia. In fact, the whole idea of relativistic mass is outdated and isn’t used in scientific circles anymore; they just call it “energy”.

The point is that you cannot “tap” this energy(relativistic mass) to increase the object’s velocity, anymore than you could “tap” the 50 Joules of kinetic energy possessed by a 1kg mass moving at 10m/s to speed the mass up further.

55. Tim Clark says:

E.M.
You must be trading today. Did you go short?

56. P.G. Sharrow says:

on June 4, 2010 at 8:39 am ScientistForTruth

“Why the difference? Because of time and other dilation effects. Things going on in your reference frame don’t appear dilated to you, but things going on in your reference frame appear highly dilated to the external observer. And things in his reference frame appear highly dilated to you.”

What is a highly dilated effect? What does one look like? Explain. has any one seen one? pg

57. P.G. Sharrow says:

Relativity is easy.

‘The number of relatives is proportional to the amount of money they think you have and inverse to the amount of money they think they have.’ pg

58. P.G. Sharrow says:

That speed of light is fixed relative to the viewpoint of the detector or observer. This may be due to sensor error as every thing we use to detect and measure photonic energy is built around it.

At least this gives some room to create grand arguments.

59. P.G. Sharrow “What is a highly dilated effect? What does one look like? Explain. has any one seen one? pg”

Yes, time dilation regularly observed in high energy physics. Particles produced from nuclear bombardment decay with a certain half life. Some half lives are short enough to use as markers for time dilation. By varying the bombardment technique and acceleration it is possible to produce such particles travelling at different speeds. The faster these particles travel, the longer is the measured half life, in accordance with relativistic theory. If they are travelling at close to the speed of light the effect is very pronounced. For example, muons accelerated to 99% the speed of light have around 10 times the half life of slow muons. From our perspective, time in the muon’s frame of reference has slowed down. From the muon’s perspective, time carries on as normal.

60. E.M.Smith says:

@Tim Clark:

Nope. Took the day off. Yeah, let money slide by. Needed to deal with some car issues and some “graduation” planning for next week and went on a date with the spouse and …

I’d looked at it Thursday and thought “Often drops on Fridays. Flat after a rebound often resolves to the downside. Had a hop up with no followthrough. Short trade ought to work.” followed closely by “I’m in cash, I think I’ll just sit in cash and go do something fun…”

Like I said before, I’m not much of a short directional trade guy. It’s a “Polish Point” for me ;-) and my current style is just to go to cash or hedge to balanced book. It’s 1/2 a loaf…

So I spot the moment reliably, but something about the context makes it hard for me to pull the trigger on the short trade. I’m working on it 8-}

@ScientistForTruth:

I’ve sometimes pondered if the photon is not just a bit of a particle at the moment of decay, and we would see it decay, but it is traveling at the ‘speed of light’ so it takes an infinite amount of time to decay to energy. Until it hits something ;-)

Yeah, just an interesting ‘thought experiment’… how would you detect the difference? And perhaps the dual particle / wave nature is just because it is actually on the cusp of turning from particle to energy… Have no idea if there is any truth in it, but it’s a fun thought.

@Janus:

Hmm… I’d forgotten that the different species might well have very different reaction kinetics. My basic assumption (unstated and unthought) was that the two types of hydrogen reactions would have substantially similar kinetics. There is no reason to believe that… So take a load of highly reactive stuff in a poorly constrained environment, the energy release overcomes the tin can. Put a load of barely reactive stuff in a very deep gravity well, it reacts, but not enough to blow the gravity trap apart. Got it. Thanks!

61. @E.M.Smith “I’ve sometimes pondered if the photon is not just a bit of a particle at the moment of decay, and we would see it decay, but it is traveling at the ‘speed of light’ so it takes an infinite amount of time to decay to energy. Until it hits something ;-)”

Interesting thoughts. The standard view is that as the photon has no mass it can/will travel at the speed of light (the speed of which can be predicted from static measurements as I described earlier). And since it travels at the speed of light there is no passage of time within the reference frame of the photon between emission and absorption. So, for example, the light even from near stars takes years to reach here, but is instantaneous to the photon.

Then the standard view in quantum mechanics (Bruce of Newcastle raised this topic in relation to the Scharnhorst effect) is really challenging to those unfamiliar with the concepts. This introduces the concept of collisions between photons and ‘virtual’ particles in a vacuum. Free space has what are called vacuum fluctuations and so is filled with virtual subatomic particles. A photon travelling through a vacuum interacts with these virtual particles to give rise to a real electron-positron pair (a positron is antimatter). This pair instantly annihilates producing a photon identical to the one that was previously absorbed.

I say identical, but the Scharnhorst effect (which has so far been too small to measure) suggests that under certain conditions a very tiny change in velocity can occur. Moreover the creation and annihilation of the electron-positon pair can’t be instantaneous but must take some time, however small; moreover these particles don’t quite travel at light speed. So, if these effects really do occur ‘something’ must happen in time, however brief. The Scharnhorst effect is interested in superluminal effects, but I wonder whether there is a related effect such that instead of a change in velocity there is a miniscule decrease in momentum. This would cause a corresponding increase in wavelength/decrease in frequency. It could be an almost infinitessimally small effect over distances and timescales over which we could do controlled measurements, but in relation to light from distant galaxies might this be a hypothetical explanation for redshifting with distance rather than expansion of the universe? Just a thought.

62. Soronel Haetir says:

An area where time dilation effects show up in mundane life is the GPS. The on-board clocks tick about 38 microseconds faster per day than a clock on earth.

63. Big Al says:

There once was a lady named Bright

Who’s speed was much faster than light

She went on her way, in a relative way

And returned the previous night!

64. @Soronel Haetir

“An area where time dilation effects show up in mundane life is the GPS. The on-board clocks tick about 38 microseconds faster per day than a clock on earth.”

True enough. For GPS timing is absolutely critical as position is determined by triangulation and timings need to be accurate to within a few nanoseconds. For readers who might wonder why the GPS clocks run faster (instead of slower) since they are travelling at high speed in orbit with respect to an observer on earth, the reason is as follows: special relativity predicts a slowing of 7us due to the relative speeds. However, general relativity predicts a speeding up of 45us due to the lower gravitational field at orbital ‘altitude’. Overall, therefore, the GPS clocks run 38us faster. Because of this they are adjusted to run 38us per day slower before launch so that they run at the correct rate when in orbit. Additionally, GPS receivers perform corrections for slight relativistic effects depending on location. If corrections were not made for relativistic effects, GPS would fail to work after only a minute or two of operation.

As I mentioned before, Einstein’s theories might not be the last word on the matter, but they clearly serve pretty well for the technologies we have today. Likewise, Newtonian physics served very well for most practical applications for over 200 years.

65. Janus says:

@ScientistForTruth
“but I wonder whether there is a related effect such that instead of a change in velocity there is a miniscule decrease in momentum. This would cause a corresponding increase in wavelength/decrease in frequency. It could be an almost infinitessimally small effect over distances and timescales over which we could do controlled measurements, but in relation to light from distant galaxies might this be a hypothetical explanation for redshifting with distance rather than expansion of the universe? Just a thought.”

This sounds like a rehash of the “tired light” hypothesis, which is no longer taken seriously.

Some problems that come to mind:

Where does the momentum go? As an conserved property, it cannot just disappear.

Secondly, since different frequencies of light have different energies, so will the electron-positron pairs created. I don’t see how the resulting redshift can be constant throughout the spectrum. The spectral lines would either be compressed together or spread apart.

Thirdly, It wouldn’t account for the associated time dilation. For example if you had a source that turned on and off in one sec intervals, your model would show a redshift, but you would still see the interval as one sec. The recession model predicts that the observed interval would increase along with the redshift. It is the second case that is seen in astronomical observations.

66. @Janus
I wasn’t propounding it as THE explanation for redshift, but merely thinking aloud. Something must give rise to redshift, and it sure isn’t expansion of spacetime. There is no indisputable evidence of an expanding universe that I’m aware of. Hypotheses built on phenomena such as redshift were perfectly valid when first propounded (say, back in the 1930s), but they have long been falsified.

By the way, I’m not sure whether you are contradicting the standard quantum model that does posit photonic interaction with virtual particles and generation and annihilation of electron-positron pairs along the ‘trajectory’ of a travelling photon.

As far as astronomy and cosmology are concerned, we are on far shakier ground than near-earth observations as we are dealing with distances and phenomena that we don’t stand a chance of verifying.

As far as ‘tired light’ is concerned, there may well have been some proposals as to how light could tire that have been eliminated, but although cosmologists holding to the Standard Model would like to think the concept discredited, it has not been disproved.

As far as conservation of momentum is concerned, this would appear to be the case in the world as we currently perceive it, but I would hesitate to say that our very limited experience of the universe is the final word on that. Newtonian mechanics appeared to cover and explain all phenomena until a little over 100 years ago; now we know that there are vast number of applications where it does not apply even as a satisfactory approximation (GPS is one that affects many of us everyday). If, indeed, photons experience billions of collisions with virtual particles (annihilating the photon, generating matter-antimatter particle pairs, which are then annihilated, generating another photon) on their journey of trillions of miles, I think it is a tremendous act of faith to believe that there could not possibly be any observable effect of this whatsoever. I’m not saying there HAS to be evidence of the effect, but it is an act of faith to believe that there definitely is not.

The Scharnhorst effect, for example, has to date not been measurable as it is predicted to introduce velocity changes of only 1 part in 10^36, which is smaller than measurement error in the laboratory. On the other hand, vacuum fluctuations creating and annihilating virtual particles have been measured – or at least an effect in accordance with quantum theory has been detected. From this, the likelihood of interaction of photons with virtual particles (and thus phenomena such as the Scharnhorst effect) would appear to be strengthened (from a Bayesian point of view).

As for the time dilation, the evidence for that with respect to the most distant galaxies is far from impressive. If you are referring to supposedly standard events like supernovae (supposedly the time to peak emission and decay are longer for more distant supernovae) then more recent analysis shows that these are far from standard anyway (the sample size had previously been pretty small – only around 2 ‘suitable’ supernovae per galaxy per century), so the conclusions drawn about them in the past have been false, wishful thinking and experimenter bias.

67. BlueIce2HotSea says:

I brought up your exact point, EM Smith, in a “Modern Physics” class some thirty-five years ago, that near light-speed travel would be possible using mass-to-energy conversion propulsion. (I got the idea from a sci-fi book.) I was humiliated when the professor repeatedly said my point made no sense. Later, I ran into the head of the physics dept. at a party. He said, “Of course it would be possible, who’s your professor?” I told him and he replied, “Oh that guy. He’s an idiot!”

My point, I guess, is that the road you are going down, is a lot of fun, but at some point you may find that no professional scientist will be interested in looking at your perfectly correct aether calculations. Many people are strong at recalling what they have been taught, but weak at independent novel analysis. I have ran into such people everywhere I have worked, including people with impressive academic credentials.

Later, I nearly got tossed from that class when I suggested that the microwave-background radiation might be useful as an absolute reference frame for traveling spaceships by measuring its doppler shift!

Had to chime in on this. Thanks for the post.

68. Janus says:

@BlueIce2HotSea

Well, there’s Possible and then there’s “possible”

Assuming that you have 100% efficient matter to energy conversion and you use the resulting photons as your exhaust, you can use the relativistic rocket equation to determine how much fuel you need to reach any given speed.

v= c*tanh(Ve/c * ln(MR)

where MR is the ratio of fully fueled ship to unfueled ship.

With Ve (the exhaust velocity) equaling c, and if we measure v as multiples of c, we can solve for MR and get:

MR = e^(atanh(v))

For 0.99c this gives a mass ratio of 14.1 ( the fully fueled ship masses 14.1 times the empty ship.

For 0.999c you get a MR of 44.7
0.9999c gives you 141.
etc.

Now keep in mind that the “empty mass” of the ship includes such things as the mass of the superstructure, engines, fuel storage system etc, so your fuel to payload ratio is going to be even higher.

Also keep in mind that the only way to do a 100% matter to energy conversion is by combining antimatter with matter. This means that you need a storage system for the antimatter. This is going to be massive and use energy itself.

As a result, not all of the energy produced by the reaction can be used for propulsion. Even a reduction to 75% increases the above mass ratios to 34, 159 and 737.

In addition, there are no readily available antimatter resources. The antimatter has to be made, with even further efficiency losses. So we are looking at a huge amount of resources needed to deliver a relatively small payload.

Oh, and I didn’t even factor in the increase of fuel to payload ratio needed if you want to bring your ship to a rest at the end of its trip ( which case, our 14.1 MR for .99c jumps to almost 200.)

69. E.M.Smith says:

ScientistForTruth

@Janus
I wasn’t propounding it as THE explanation for redshift, but merely thinking aloud. Something must give rise to redshift, and it sure isn’t expansion of spacetime. There is no indisputable evidence of an expanding universe that I’m aware of. Hypotheses built on phenomena such as redshift were perfectly valid when first propounded (say, back in the 1930s), but they have long been falsified.

My favorite “odd thought” about the expanding universe is that it isn’t. It’s being consumed…

The “singularity” in a black hole is where space and time cease to exist. As ‘stuff’ falls into a black hole, it accelerates (eventually toward the speed of light, so time dilates, and from our perspective we might not ever see things actually ‘go away’ as their time would slow down and they would seem to be plastered all over the event horizon… but that’s another wondering…)

As they speed up, they gain mass (from our perspective) causing the black hole to become ever more massive. And thus sucking in even more stuff at even higher speeds.

All this massiveness distorts space, sucking the very fabric of space into the black hole with the ‘stuff’…

And as we all know, if you pull a pucker in a fabric the areas all around will be stretched….

So perhaps the ‘expansion of the universe’ is really just space time being stretched as various black holes all over the place suck the fabric of space time into them… to enter the singularity and cease to be…

(On a related note, the rest of this theory of mine is that the space / time and all the matter the enter all the black holes of the universe eventually ‘pop out again’ in a white hole. The only one we know of is The Big Bang. And since time itself ceases to exist as it enters a singularity, it would be perfectly reasonable for all the space and stuff to pop out again at the beginning to time (where all the space and stuff is just beginning too….).

In this sense, the white hole at the big bang is just the result of conservation of momentum as space, time, and matter cease to be in the black hole singularities at the ‘end of time’ when the last vestiges of the space / time fabric have been sucked down the (by then near infinite) massive gravity wells of ancient super duper massive black holes. It also explains why all the matter appears ‘at once’ and ‘from nowhere’. It may fall into the black holes over billions of years of “our time” but all comes together in the singularity at ‘no time’ and it all comes from ‘no where’ as that is where it all went… as space itself ceased to be.

In this way, we can have the “expansion of the universe” but without stuff actually moving to an infinite “somewhere else”, it’s just going down a relativistic drain “forward to the past” ;-)

Isn’t relatively mixed with black holes fun 8-}

No idea how to test or ‘prove’ the idea, though…

@Janus:

As I understand it, you start getting significant time dilation at just 80% or so of C, so very long trips ought to be possible at less than 14:1 mass ratios (as long as you don’t mind losing a decade or two off your relatives lifespans back home…)

I think it ought to be possible to make a 2 x or even a 4 x time multiplier with reasonable engineering. So a star 40 years away at ‘our time’ could be reached in 10 years of ‘ship time’. I know folks who would take that trip… ( I would not mind seeing the world of 20 years in the future… so I’d sign up for a 5 year ship time round trip.)

70. BlueIce2HotSea says:

@Janus

Well, here’s some more cold water, “Who’s going to pay for it?”

But, putting aside engineering and financing, what do your calculations say about an electro-static ramjet which scoops its fuel along a pre-seeded trajectory, followed by braking via magnetic sail? Don’t think light-speed luxury hotel, here; start with a nano-robot ship.

In any event, the original objection I ran into regarding the acceleration of macroscopic objects to light-speed was F=ma. That is, given constant thrust, relativistic mass increases would cause acceleration to fall off toward zero and end any increase in velocity. However, that is not true for thrust derived from mass-to-energy-conversion; both thrust and mass would increase proportionally.

Cheers
BlueIce

71. Janus says:

@BlueIce2HotSea
“But, putting aside engineering and financing, what do your calculations say about an electro-static ramjet which scoops its fuel along a pre-seeded trajectory, followed by braking via magnetic sail? Don’t think light-speed luxury hotel, here; start with a nano-robot ship.”

As I pointed out in an earlier post, Thee is a limiting speed to a ramjet. At some point, the drag induced by collecting the fuel equals the thrust produced by it. At this point all the ship can do is maintain that speed. The maximum estimate for that top speed is less than 10% of c.

“In any event, the original objection I ran into regarding the acceleration of macroscopic objects to light-speed was F=ma. That is, given constant thrust, relativistic mass increases would cause acceleration to fall off toward zero and end any increase in velocity. However, that is not true for thrust derived from mass-to-energy-conversion; both thrust and mass would increase proportionally.”

I also covered this in a earlier thread. The increase in mass is “relativistic mass” which is really just another term for “energy”, And this energy came from the fuel you’ve already used. You cannot use this again to power your engines.

Here’s another way of looking at it: The relativistic increase in mass, is only measured in the frame which with respect to, the ship is moving. But in that frame, time on the ship runs slow, the ship’s length is contracted, and there is a loss of simultaneity. This means that the rate at which the fuel is used and the speed at which it is exhausted from the ship decreases, which results in a decrease in thrust as the ship approaches c.

For example, traveling at .99c with an exhaust speed (as measured from the Ship) of .1c, the relativistic mass increase is a factor of 7. The exhaust speed as measured by someone for which the ship is moving at .99c is only .0022 c or 1/45 the .1c as measured form the ship. So even if the mass of the exhaust gases has increased by a factor of 7 to offset the increase in mass of the rest of the ship( which it won’t exactly, as it will now be moving slightly slower than the ship and will have a smaller mass increase), the thrust, due to the lower exhaust speed has decreased by quite a bit.

No matter how you cut it, the aceleration decreases for the ship as measured from the “stationary” frame, even though it remains constant in the ship frame.

72. BlueIce2HotSea says:

@Janus
“(There) is a limiting speed to a ramjet.”

You were referring to a Bussard ramjet (electro-magnetic scoop). However, I asked for your opinion on the electro-static ramjet; it supposedly avoids the drag problem. Do you claim drag is a limiting factor for an electro-static ramjet?

“You cannot use this (relativistic mass) again to power your engines.”
Yes. This is obviously true or we have a perpetual motion machine. My apologies to all and especially to my professor of long ago.

You seem to be claiming that an observer on the spacecraft would experience both constant acceleration AND failure to increase velocity. Please clarify what is obseserved from the reference frame of the spaceship.

Cheers
BlueIce

73. Janus says:

@E.M.Smith

“As they speed up, they gain mass (from our perspective) causing the black hole to become ever more massive. And thus sucking in even more stuff at even higher speeds.”

No. The increase in speed is due to the conversion of potential energy to kinetic energy. Since the total energy of the falling object does not change, neither does its relativistic mass as seen by a distant observer. IOW, if I am a far removed observer measuring the combined gravity of both the black hole and the object falling into into it, I will measure no difference between when the object is far removed from the black hole from when it is right at the event horizon.

“All this massiveness distorts space, sucking the very fabric of space into the black hole with the ‘stuff’…

And as we all know, if you pull a pucker in a fabric the areas all around will be stretched….”

Space cannot be treated like a material substance. When one talks about space “curving” near a mass, what is really meant is that space in that region becomes non-Euclidean. It just means that rules of geometry follow different rules. The easiest way to visualize these rules is to imagine that the 3 spacial dimensions are “curved” through a 4th spacial dimension. In reality there is no 4th spacial dimension, the rules just mimic such a case.

“@Janus:

As I understand it, you start getting significant time dilation at just 80% or so of C, so very long trips ought to be possible at less than 14:1 mass ratios (as long as you don’t mind losing a decade or two off your relatives lifespans back home…)

I think it ought to be possible to make a 2 x or even a 4 x time multiplier with reasonable engineering. So a star 40 years away at ‘our time’ could be reached in 10 years of ‘ship time’. I know folks who would take that trip… ( I would not mind seeing the world of 20 years in the future… so I’d sign up for a 5 year ship time round trip.)”

At 80% of c the time dilation factor is 1.6667 (a trip of 40 light years would take 50 yrs Earth time and 30 yrs ship time.

The 14:1 mass ratio gets you up to 99% of c which gives you a time dilation factor of 7.

A mass ratio of 4 will get you to 88% of c, this gives a time dilation factor to just a bit over 2. (again, this is assuming 100% efficiency.) But this only gets you up to this speed, to stop at the other end you need a MR of 16. A round trip causes it to jump up to 256.

Also, you won’t be traveling at that speed the whole trip. You have to accelerate up to speed and slow back down. Since you’ll want to be comfortable, so you likely accelerate at 1g.

For a five year round trip (ship time) you accelerate for 1.25 yrs, reaching a top speed of 85.8% of c, decelerate for another 1.25 yrs, and then repeat for the return trip.

This will take 6.5 years Earth time, and you will only reach a distance of 1.845 light years from Earth (not even half the distance to Alpha Centauri.)

74. Janus says:

BlueIce2HotSea
@Janus
“You were referring to a Bussard ramjet (electro-magnetic scoop). However, I asked for your opinion on the electro-static ramjet; it supposedly avoids the drag problem. Do you claim drag is a limiting factor for an electro-static ramjet?”

I don’t see how it could be otherwise. You are still gathering up interstellar gasses in order to compress them for fuel. There will still be a velocity difference between the ship and these gases, so some of the momentum of the ship will be lost in the process. At some point, the increasing velocity difference will result in a momentum loss that can’t be made up for by burning the fuel. I can’t say how much switching to electrostatic collection reduces the drag compared to electromagnetic, because I haven’t seen the studies on it, But I have a feeling that you still aren’t going to be able to get up to those high fraction of c speeds.
You seem to be claiming that an observer on the spacecraft would experience both constant acceleration AND failure to increase velocity. Please clarify what is obseserved from the reference frame of the spaceship.

“You seem to be claiming that an observer on the spacecraft would experience both constant acceleration AND failure to increase velocity. Please clarify what is obseserved from the reference frame of the spaceship.”

This can easily visualized by considering the addition of velocities theorem:

w = (u+v)/(1+uv/c^2)

Imagine that your ship is dropping buoys along the way that maintain the ship’s velocity with respect to the starting point at the moment of release.

The ships accelerates to .1c, and releases a buoy. The ship now (from its perspective) accelerates to .1c relative to the buoy. How fast is the ship moving with respect t the starting point? using the above equation, we get .198c. (not .2c)

Drop another buoy, which by its perspective is traveling at .198c relative to the starting point. Accelerated to .1c relative to it. By your perspective, you are moving at .292c relative to the starting point. Do it again and you are moving at .381c.

No matter how many times you do this, your resulting velocity with respect to the starting point will always remain below c, even though, by your perspective, you were accelerating at a constant rate.

75. P.G. Sharrow says:

While all you armchair engineers are playing suppose you accelerate at 1ge (32 ft per sec.-per second) how long to C? :-) pg

76. Janus says:

@P.G. Sharrow

“While all you armchair engineers are playing suppose you accelerate at 1ge (32 ft per sec.-per second) how long to C? :-) pg”

Forever.

The formula for finding the ship time needed to reach any given velocity is:

t= atan(v/c)*c/a

where a is the acceleration experienced by the ship.

As v approaches c, t approaches infinity.

If you plug c in for v, you get a division by zero error. ( atan (v/c) = ln{[1+v/c][1-v/c]}/2)

77. BlueIce2HotSea says:

@Janus
Your explanation seems to mix and match reference frames. The laws of physics should remain consistent, although fixing that won’t change the more bleak outlook for light-speed travel.

What I mean is, if a spaceship sustains a 1g acceleration for 353 days, as measured by an observer on that craft, by definition it achieves a continuous linear ascent to light-speed. Unfortunately, at that point, the traveler is seeing the instantaneous approach of what only one year earlier was the end of the visible universe. Meanwhile, back on planet earth, the craft is seen as consuming billions years to reach light-speed, as per your prediction. No?

@BlueIce
“…we have a perpetual motion machine. My apologies…”

I want to back off slightly from this.

First, a better explanation is to recognize that the rocket thrust comes from rest-energy \ rest-mass (i.e. matter). It might be chemical, nuclear, matter-anti-matter, etc. But that is a completely different animal than the energy of relativistic mass, which is solely kinetic. The loss of kinetic energy would result in negative acceleration, not positive.

Finally, as I paid for my class on Special Relativity, some apology is probably owed me by the two physics professors who could not explain to me what both Janus and EM Smith have helped to illuminate in a couple of posts. I still regret any confusion I may have caused.

Cheers,
BlueIce

78. Janus says:

@BlueIce2HotSea

“Your explanation seems to mix and match reference frames. The laws of physics should remain consistent, although fixing that won’t change the more bleak outlook for light-speed travel.”

The addition of velocities theorem is exactly designed for this type of scenario. It basically says that if u is the velocity of object B in one direction with respect to A, and v is the velocity of object C in the other direction with respect to A, then the velocity of B with respect to C as measured by either B or A is found by:

W=(u+v)/(1+uv/c^2) In the example I gave, each buoy is object A for any given calculation while u is the buoy’s velocity with respect to the Earth and v is the ship’s velocity with respect to the ship.

What I mean is, if a spaceship sustains a 1g acceleration for 353 days, as measured by an observer on that craft, by definition it achieves a continuous linear ascent to light-speed. Unfortunately, at that point, the traveler is seeing the instantaneous approach of what only one year earlier was the end of the visible universe. Meanwhile, back on planet earth, the craft is seen as consuming billions years to reach light-speed, as per your prediction. No?

No. After 353 days(ship time), the ship will have reached a speed of 76% of c as measured by both ship and Earth (though according to the Earth, the time passed will be 414 days), and traveled a distance of 0.52 light years (as measured from Earth. According the ship that 0.52 ly has contracted to 0.34 ly)

IOW, the observer on the ship will note that he has only traveled 12% of the distance to Alpha Centauri.

79. BlueIce2HotSea says:

Thank you Janus.

I can once again use the additions of velocities theorem to answer exam questions. And I now see that it would take approx. 2 yr. (ship ref-frame) to get to .97c, not the 342 days by my prior simple calc method.

“…according to the Earth, the time passed will be 414 days…”

However I get 400 days, not 414, using the relativistic rocket eq:

t = (c/a)*sinh(aT/c)

where c=1 lyr/yr, a= 1g = 1.03 lyr/yr**2, T=353/365.25 yr

“…the observer on the ship will note that he has only traveled 12% of the distancet to Alpha Centauri.”

But 12% of the distance to Alpha Centauri (4.37 lyr) = .52 lyr,, the same distance you give as seen from earth. (You keep transporting yourself back to earth’s reference frame.)

More importantly, why doesn’t the remaining distance to the star, as seen from the ship, undergo relativistic length contraction?

Cheers,
BlueIce

80. BlueIce2HotSea says:

@BlueIce2HotSea

“why doesn’t the remaining distance to the star, as seen from the ship, undergo relativistic length contraction?”

I will answer this and hope my explanation doesn’t require cleanup by Janus.

The remaining distance to the star, as seen from the ship, MUST undergo relativistic length contraction, otherwise the travelers would die of old age on much longer trips. It’s an incomplete explanation to say that time dilation causes a slowing of both biological and mechanical clocks, for on board the spaceship no such clock slowing is detectable. Instead, the distances would be dramaticially shortened from their perspective and thereby easily traversible in years, rather than millenia.

That means that the remaining distance to the star, for the .76c spaceship, would be shortened by a factor of (1-(.76)**2) = .65 as compared to a nearby observer that was stationary with respect to earth.

Cheers,
BlueIce

81. BlueIce2HotSea says:

oops, (1-(.76)**2)**.5 = .65

BlueIce

82. Janus says:

@BlueIce2HotSea

“Thank you Janus.

I can once again use the additions of velocities theorem to answer exam questions. And I now see that it would take approx. 2 yr. (ship ref-frame) to get to .97c, not the 342 days by my prior simple calc method.

“…according to the Earth, the time passed will be 414 days…”

However I get 400 days, not 414, using the relativistic rocket eq:

t = (c/a)*sinh(aT/c)

where c=1 lyr/yr, a= 1g = 1.03 lyr/yr**2, T=353/365.25 yr”

The difference is due to rounding variances. I converted everything to the MKS system before calculating, used 9.8 m/s^2 for a, and rounded c to 3e8 m/s.

“…the observer on the ship will note that he has only traveled 12% of the distancet to Alpha Centauri.”

But 12% of the distance to Alpha Centauri (4.37 lyr) = .52 lyr,, the same distance you give as seen from earth. (You keep transporting yourself back to earth’s reference frame.)

More importantly, why doesn’t the remaining distance to the star, as seen from the ship, undergo relativistic length contraction?”

It does. The 0.34 ly the ship has traveled from Earth by its measurement is 12% of the distance it measures between Earth and Alpha Centauri(2.83 ly).

IOW, if we put a marker at a point 12% of the distance to Alpha C., both an observer on Earth and and observer on the ship will agree that the ship clock reads 353 days when the ship is even with the marker.

83. BlueIce2HotSea says:

@Janus

Bravo, well done.

84. P.G. Sharrow says:

Very good!

The only point of view that is important is the space travelers’. Acceleration to mid point and deceleration to destination. The travelers point of view is the only relative limit. However to the rest of the universe the traveler is packing one hell of a mass/inertia. 8-0

Now get rid of the reaction engine and use an EMF drive and this is an energy problem only. pg

85. P.G. Sharrow says:

Space is a very large place even at near light speeds. The travelers time is all that is important.

86. Paul M Who says:

Hi Chiefio