Strange as that may sound, it’s true. Just no people involved.
See, small stars degenerate into White Dwarf stars. Some of these gather just enough excess matter to blow up and become a Type 1a Supernova. A supernova in your neighborhood pretty much means you are toasted to a cinder.
But what is the composition of those White Dwarf stars? Carbon & Oxygen.
A white dwarf, also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to that of the Sun, while its volume is comparable to that of Earth. A white dwarf’s faint luminosity comes from the emission of stored thermal energy; no fusion takes place in a white dwarf wherein mass is converted to energy. The nearest known white dwarf is Sirius B, at 8.6 light years, the smaller component of the Sirius binary star. There are currently thought to be eight white dwarfs among the hundred star systems nearest the Sun. The unusual faintness of white dwarfs was first recognized in 1910. The name white dwarf was coined by Willem Luyten in 1922.
I’ll ignore for the moment that Sirius is in fact a triple star system.
It is just a wiki after all…
So we’ve got at least 8 of those suckers near us, and one of them at least has nearby partners. Part of how a White Dwarf comes to blow up is by accumulating matter from a partner star in a binary (or in this case trinary) system. So most likely it’s just a matter of time till one of those near us blows up.
LAWRENCE — In 2016, researchers published “slam dunk” evidence, based on iron-60 isotopes in ancient seabed, that supernovae buffeted the Earth — one of them about 2.6 million years ago. University of Kansas researcher Adrian Melott, professor of physics and astronomy, supported those findings in Nature with an associated letter, titled “Supernovae in the neighborhood.”
Melott has followed up since those findings with an examination of the effects of the supernovae on Earth’s biology. In new research to appear in Astrophysical Journal, the KU researcher and colleagues argue the estimated distance of the supernova thought to have occurred roughly 2.6 million years ago should be cut in half.
“There’s even more evidence of that supernova now,” he said. “The timing estimates are still not exact, but the thing that changed to cause us to write this paper is the distance. We did this computation because other people did work that made a revised distance estimate, which cut the distance in half. But now, our distance estimate is more like 150 light years.”
A supernova exploding at such a range probably wouldn’t touch off mass extinctions on Earth, Melott said.
“People estimated the ‘kill zone’ for a supernova in a paper in 2003, and they came up with about 25 light years from Earth,” he said. “Now we think maybe it’s a bit greater than that. They left some effects out or didn’t have good numbers, so now we think it may be a bit larger distance. We don’t know precisely, and of course it wouldn’t be a hard-cutoff distance. It would be a gradual change. But we think something more like 40 or 50 light years. So, an event at 150 light years should have some effects here but not set off a mass extinction.”
OK, 40 to 50 light years. And we have a White Dwarf at a little over 8, with companions, and at least 7 more near by. Oh Joy… /sarc;
So back at the wiki about how these things form:
White dwarfs are thought to be the final evolutionary state of stars whose mass is not high enough to become a neutron star, which would include the Sun and over 97% of the other stars in the Milky Way. After the hydrogen-fusing period of a main-sequence star of low or medium mass ends, such a star will expand to a red giant during which it fuses helium to carbon and oxygen in its core by the triple-alpha process. If a red giant has insufficient mass to generate the core temperatures, around 1 billion K, required to fuse carbon, an inert mass of carbon and oxygen will build up at its center. After such a star sheds its outer layers and forms a planetary nebula, it will leave behind a core, which is the remnant white dwarf. Usually, white dwarfs are composed of carbon and oxygen. If the mass of the progenitor is between 8 and 10.5 solar masses (M☉), the core temperature will be sufficient to fuse carbon but not neon, in which case an oxygen–neon–magnesium white dwarf may form. Stars of very low mass will not be able to fuse helium, hence, a helium white dwarf may form by mass loss in binary systems.
So there you have it. Our Sun, destined to become a Carbon/Oxygen White Dwarf and kill us all in the process, then nova if enough mass falls into it. Along with 97% of the other stars. We’re going to be surrounded by CO / CO2 bombs.
Carbon detonation or Carbon deflagration is the violent reignition of thermonuclear fusion in a white dwarf star that was previously slowly cooling. It involves a runaway thermonuclear process which spreads through the white dwarf in a matter of seconds, producing a Type Ia supernova which releases an immense amount of energy as the star is blown apart. The carbon detonation/deflagration process leads to a supernova by a different route from the better known Type II (core-collapse) supernova (the type II is caused by the cataclysmic explosion of the outer layers of a massive star as its core implodes).
A white dwarf is the remnant of a small to medium size star (our sun is an example of these). At the end of its life, the star has burned its hydrogen and helium fuel, and thermonuclear fusion processes cease. The star does not have enough mass to either burn much heavier elements, or to implode into a neutron star or type II supernova as a larger star can, from the force of its own gravity, so it gradually shrinks and becomes very dense as it cools, glowing white and then red, for a period many times longer than the present age of the Universe.
Occasionally though, a white dwarf gains mass from another source – for example a binary star companion that is close enough for the dwarf star to siphon sufficient amounts of matter onto itself or a collision with other stars, the siphoned matter having been expelled during the process of the companion’s own late stage stellar evolution. If the white dwarf gains enough matter, its internal pressure and temperature will rise enough for carbon to begin fusing in its core. Carbon detonation generally occurs at the point when the accreted matter pushes the white dwarf’s mass close to the Chandrasekhar limit of roughly 1.4 solar masses. This is the mass at which gravity can overcome the electron degeneracy pressure which had prevented the star from collapsing during its lifetime. The same also happens when two white dwarfs merge and the mass of the body formed is below the Chandrasekhar limit; if two white dwarves merge and the result is over the limit, a Type 1a supernova will occur.
A main sequence star supported by thermal pressure would expand and cool which automatically counterbalances an increase in thermal energy. However, degeneracy pressure is independent of temperature; the white dwarf is unable to regulate the fusion process in the manner of normal stars, so it is vulnerable to a runaway fusion reaction.
In the case of a white dwarf, the restarted fusion reactions releases heat, but the outward pressure that exists in the star and supports it against further collapse is initially due almost entirely to degeneracy pressure, not fusion processes or heat. Therefore, even when fusion recommences the outward pressure that is key to the star’s thermal balance does not increase much. One result is that the star does not expand much to balance its fusion and heat processes with gravity and electron pressure, as it did when burning hydrogen (until too late). This increase of heat production without a means of cooling by expansion raises the internal temperature dramatically, and therefore the rate of fusion also increases extremely fast as well, a form of positive feedback known as thermal runaway.
The flame accelerates dramatically, in part due to the Rayleigh–Taylor instability and interactions with turbulence. The resumption of fusion spreads outward in a series of uneven, expanding “bubbles” in accordance with Rayleigh–Taylor instability. Within the fusion area, the increase in heat with unchanged volume results in an exponentially rapid increase in the rate of fusion – a sort of supercritical event as thermal pressure increases boundlessly. As hydrostatic equilibrium is not possible in this situation, a “thermonuclear flame” is triggered and an explosive eruption through the dwarf star’s surface that completely disrupts it, seen as a Ia supernova.
Regardless of the exact details of this nuclear fusion, it is generally accepted that a substantial fraction of the carbon and oxygen in the white dwarf is converted into heavier elements within a period of only a few seconds, raising the internal temperature to billions of degrees. This energy release from thermonuclear fusion (1–2×1044 J) is more than enough to unbind the star; that is, the individual particles making up the white dwarf gain enough kinetic energy to fly apart from each other. The star explodes violently and releases a shock wave in which matter is typically ejected at speeds on the order of 5,000–20000 km/s, roughly 6% of the speed of light. The energy released in the explosion also causes an extreme increase in luminosity. The typical visual absolute magnitude of Type Ia supernovae is Mv = −19.3 (about 5 billion times brighter than the Sun), with little variation. This process, of a volume supported by electron degeneracy pressure instead of thermal pressure gradually reaching conditions capable of igniting runaway fusion, is also found in a less dramatic form in a helium flash in the core of a sufficiently massive red giant star.
So there you have it folks. Carbon Dioxide and Carbon Monoxide are going to destroy the solar system and it’s all your fault. Send grant money so we can find ways to mitigate this Carbon Detonation and save the children so they can see snow again and kittens can play with puppies.
We all knew CO2 was going to destroy the planet, now it is confirmed as inevitable. No more than 10 or 20 billion years and it’s guaranteed that’s where we end up. But not only that, it’s far worse than we thought! With 97% of stars being in this type range, every single star system with life on it is doomed. Doomed! I Say! We MUST act now to find ways to sequester this carbon where it will be safe. We simply must Save The Galaxy from these rogue racist WHITE dwarf stars. Time is running out! Send money now! or be responsible for the murder of the Galaxy! /sarc; (sort of… parody is more like it. Then again, some of the stuff published as Peer Reviewed is not that much different…)
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Bright side dark side Can;t survive without it,
but in the lo-o-ng run it will do us in. All good things
must come to an end … so sayeth Naychur.
Come on Chefieo, pull the other one. There was I following this great little story and wondering if I should confess my CO2 guilt at my next confession.
That is until I came to that magic number – ninety seven percent. 97%, now where have I seen that magic number before?
Could someone remind me please?
This is going to play hell with Star Registry, where you send in 50 bucks and they name a star after you.
KABOOM! Oops… oh well, pick another star…
Yep. I think it is possible this is why we haven’t detected other civilizations – one way or another, the universe did them in.
When one looks at the difficult conditions over the last 10 million years, it would appear that humans were created by adversity. Only the most adaptable evolve and survive. Humans seem to adapt and evolve onto nearly all of this planet. Perhaps optimism is in order…pg
@jim2; I think there is a BIG sign out there that says ” DANGER! Natives are Armed and Unfriendly.” “KEEP OUT ! …pg
The Drake equation needs to be augmented with terms that take into account the odds of extinction.
@P.G. & Jim2:
I suspect the sign instead says:
“Wild Human Preserve. Please check with the main office before entering. Only licensed researchers prepared to work in primitive conditions and with full protection and isolation equipment are allowed and must demonstrate experience at avoiding contamination and back contamination. No Exceptions.”
The Drake equation does have a longevity factor, but the devil is in the distribution.
The UIGSS has set us aside as a preserve? (United Intragalactic Star Systems).
Preserve? More likely Quarantine ! …pg
System is not massive enough to Supernova II. Entire system is only 3.2 solar masses. The vampire star needs to be a neutron core. OTOH, is massive enough to nova, providing the two stars are close enough. Sirius A & B are 20 AU apart (earth to Uranus), which might be too far for atmosphere transfer from one to the other.
Fun part is that Sirius B started out as the most massive, which is why it went white dwarf first. Where did its atmosphere go during its red giant stage? Sirius A? Is that envelope still present? Why don’t we see a planetary nebula around the Sirius system? Cheers –
@Waterside – 97% is a marketing number. So God is going the marketing route. ;-)
If the starry neighborhood is dense, then you are more likely to live among other civilizations. But you are also more likely to live near a galactic IED (Immense Explosive Device). OTOH, if your starry neighborhood is sparse, you are less likely to live near other civilizations, and won’t detect any, but have better odds of survival.
Stars move quite quickly relative to our solar system, in geological time. Sirius will only be the brightest star in our sky for the next 210,000 years, where Sirius B won’t likely explode until Sirius A reaches its red giant stage, estimated to be 500 to 750 million years from now, at which time it could be 20,000 ly from us due to its relative motion away from us.
In the meantime, the biggest threat to our biosphere is carbon starvation. We nearly reached this point during the last ice age, when CO2 levels plunged to 180ppm, just barely over the threshold at which most photosynthesis stops. Various mechanisms such as cold oceans absorbing CO2 and rocks in large mountain ranges scrubbing out the CO2 via chemical reactions, nearly killed the biosphere then.
These are long-term geological processes that will relentlessly continue working after humanity is gone (unless we somehow happen to survive on a permanent basis and permanently engineer the earth for life).
By the time the Earth gets unlucky and is within 25-40 ly of a supernova, odds are the biosphere will have been dead for millions of years.
Very interesting information from the electric universe people, they don’t believe in black holes and super novae. They initioted a project to perform detailed plasma research creating the sun in a jar pot as they say. The preliminary information they come up with is kind of flabbergasting.
“When one looks at the difficult conditions over the last 10 million years, it would appear that humans were created by adversity. Only the most adaptable evolve and survive. Humans seem to adapt and evolve onto nearly all of this planet. Perhaps optimism is in order…pg”
Does that mean we should actually thank the greenery for increasing the level of adversity?
97% of Scientists agree that anything that is important and just known to be right is best stated not as 100%, because that sounds like you are making up a percentage to sound all sciency when really it’s just your WAG (Wild Ass Guess). So since you can’t say 100%, and 95% means folks will expect to see your math to support that confidence interval rank, you pick something that ends in 7 because that’s just what people do.
(Really, they do! For reasons unknown, folks love to pick 7 as a guess / made up number. 1 and 9 are rare as they are too close to a whole number and folks are afraid it looks wimpy, and 5 is weak tea wishy washy, but 3 and 7 are Sounds Important numbers. This is actually used to look for bogus made up data, there’s a known non-random pattern that people choose…)
So yeah, 97% of Scientists agree that anything with 97% probability is absolutely true, and NOT to be questioned. (Especially no questions about methodology… or data…)
@Chris in C:
I like to point out to folks, when they are panties-in-a-bunch panicky about some geologic time scale risk, that humans have only existed for 6 millions years in any form, and “modern” Humans for a few hundred thousand years. Whatever causes extinction events in a Million Years+ will cause the extinction of something, but it won’t be a “modern human”… it will be some entirely different animal…
That’s the paradox of the galactic core. Much much much more likely there is life there from all the old dense stars, and that it can communicate with nearby civilizations. Also much much much more likely to have been snuffed out just before reaching that point…
OTOH, we’re out here in the safe and quiet boonies. Nobody to talk to, but unlikely to be exterminated Real Soon Now…
@R. de Haan:
I’m fond of the Electric Universe folks. No idea if they are right or not, but they do have a refreshing ability to make one think.
I think they are totally correct with their theory.
Not only have they come up with mighty strong evidence, they also have totally ruibed the existing consenses in Astrophysics which representatives, gate watchers and Nobel Price Laureates they crefer to as “The dark side”.
There are some mighty interesting aspects about their views.
For example they explain the mechanism that explains how it is possible that millions of tons of water and hail in a storm cloud defy gravity…. and why the inside of a solar spot is dark. And they also set no limits to the speed of space travel. They think travel beyond the speed of light is possible.
No black holes, no icy comets degassing to explain their tail, no meteorite belt, No Oort Cloud, no Big Bang, no expanding or shrinking universe, no gravity waves. Just the simplicity of an electric, plasma filled universe where all processes taking place can be explained, scaled and simulated in a laboratory. I like “simple”.
The research they have undertaken with their plasma studies provide us with lot’s of questions but also provides us with the explanation why the surface boundary of the sun is so much hotter than than surface of the sun it’s self. They are also performing break through science in regard to gravity, the molecular structure of the elements, you name it.
Over the past 5 years I have been digging through all their web sites, video’s, and peer reviewed publications. The more information I digested, the more convincing their views have become.
I think that very dollar we spend on the established orthodoxy of astrophysics is lost money because the entire approach is based on mathematic equations and models that simply do not correlate with our observations, just like the Co2 driven climate fraud
We need to start all over again with a clean sheet of paper so we can really make scientific progress.
That’s my 2 cents contribution to the casus.
Sorry for the typo’s, lost my glasses again.
@R. de Haan
Thanks for that Safire vid – amazing effects for a paltry 180W…
You are most welcome.
Beyond the Moon by Paolo Maffei I read many years ago. In it he calculated the radiation dose the earth would receive from a nearby nova. I believe I still have that book somewhere, going to have to find and report back.
Found the book…it’s rather old, first published 1973. But he references a study by K D Terry and W H Tucker in which a type II nova 600 ly away would produce a cosmic ray flux of 500 roentgens. The nearby stars should produce a type II nova every 50M years
Of course the key question is how long would the duration of that 500 R exposure be?
That is roughly the LD50 dose if received as an acute dose. Is that total dose or dose rate / hour.
If the pulse lasted a short period of time only the star facing side of the planet would be exposed, if the exposure lasted about 24 hours the earth would turn away from the star (for any local individual) after about 12 hours, many of which would be at low angles to the horizon and have a long atmospheric path (and hence some attenuation). Is that the exposure at the top of the atmosphere or on the ground at sea level.
If the exposure lasted for and was spread out over several days protective action could be taken.
(how long can you stay several feet under water?)
I just found the book used on amazon and ordered it.
See “supernova,” by Roger MacBride Allen and “Eric Kotani” (Yoji Kondo), published 1991.
In it, Sirius B finally accumulates enough matter from Sirius A to flash into a Type 1a supernova…
The interesting historical referent is that the ancients had Sirius as a bright *orange* star– the theory is that Sirius B has occasionally flashed into a relatively minor “nova” reaction, thereby blowing most of the input off.
The worry is that it could (will!) eventually exceed the Chandrasekhar Limit.
Two interesting points made in their scenario:
* Even at 8.6 light-years’ distance, the glowing shell will display a visible disk, before it breaks apart!
* They believe that the gamma-ray burst that could actually disrupt our electgromagnetic systems would be released only when the shell breaks open, from the first gaps– thus there is quite a measure of Pure Chance in that threat, as the first break has to point in our direction.
Eric: The current mass of Sirius B is 1.02 solar masses; to reach the Chandrasekhar Limit it would require 0.38 solar masses (equal to ~20% of the mass of Sirius A) to fall onto it (and not get blown off in a nova).
Since Sirius B orbits a minimum of 8.2 AU from Sirius A, this is unlikely to happen until Sirius A becomes a red giant and starts shedding its its outer layers — and even then (several hundred million years from now), that would require Sirius B to capture about one-third of the shed mass to explode.
The odds of this happening while Sirius B is anywhere close to Earth (say in the next 210,000 years) are vanishingly small.
@Chris in Calgary:
There you go, ruining a perfectly good story with the facts…