Over on WUWT, on a topic about low CO2 levels during ice ages, I mentioned my belief that a large impact into the ice sheet in Canada likely caused the Clovis Extinctions. In passing (i.e. after some arguing) mentioned I thought it was likely part of the Tarids, from a break-up of the proto-Encke.
The user named “Gabro” took offense at that… and my pointing at Cosmic Tusk as a source of useful bits.
I also pointed at this article and made the connection to Encke:
Well, down below that, Agimarc points to a very interesting new article about a new Taurid stream being found, and it has some asteroid sized bits in it. h/t agimarc.
July 5, 2017 at 8:01 pm Edit
Appears the Taurid Complex has yet another stream that we cross twice a year. Cheers –
That article says:
Meteor swarm spawns new and dangerous branch
Czech boffins say source of Tunguska event has new asteroid-sized bits to watch
By Richard Chirgwin 7 Jun 2017 at 06:29
The regular and often-unspectacular Taurid meteor shower has a dangerous side, with Czech boffins warning it’s a likely source of dangerous debris.
Working at the Czech Academy of Sciences, the authors of this paper at Astronomy and Astrophysics (here at arXiv) analysed 144 fireballs observed in the 2015 Taurid shower, and say there’s a previously undiscovered branch of the swarm that needs to be watched.
The Taurids have caused problems before. Most notably, it’s believed to be the source of the famous 1908 blast near the Stony Tunguska River, attributed to 150-metre meteor from the swarm exploding in the sky over Siberia.
The largest meteor stream in the inner solar system, the Taurids are the source of four meteor showers each year – all most probably a stream of fragments created when one or more large comets broke up around 30,000 years ago.
The branch of interest to the Czech scientists is the Southern Taurids, and the fireballs caught be European Fireball Network were spotted between October 25 and November 17 2015.
From those observations, the paper argues two conclusions: the new branch has a “well defined orbital structure”, but worryingly, the branch includes asteroid-sized structures in addition to the two already known.
During the 2015 shower, the paper states the brightest fireball “was caused by a body in excess of 1000 kg, which corresponds to diameter more than one meter”.
“Based on orbital similarity, we argue that asteroids of several hundred meters in diameter are members of the Taurid new branch as well,” the researchers continue.
They also believe a Pacific Ocean fireball spotted by NASA’s JPL was also part of the branch – and it was a biggie at “ten times more massive”.
So to recap, about 25000 to 30000 years ago, a much larger proto-Encke entered the inner solar system and started breaking up. Since then, we’ve had several major known impacts, and a likely larger one causing a mass extinction focused on North America. The streams of debris have now divided into multiple sets ( 4? 5? ) and hit the Earth twice a year; and then, over a thosands year cycle, we move more central to the swarms, or more to the edge. In one set, it is known they hit with a ‘double tap’ about a 100 years apart. Throughout history, we have disasters on a thousands year period and with a double tap aspect over 100ish years. We know there are asteroid sized objects still in the stream.
We know we WILL enter the densest parts of those streams periodically and that we WILL be hit, potentially with extinction or local extirpation sized events. One well characterized collapse was in about 2200 BC. Or about 2 longer cycles ago. And it had the “double tap” structure. So the next opportunity is “about now”? (or up to 300 years from now… bit hard to say).
Oh, well then, by all means THE most important thing to discuss is who had lunch with anyone from Russia last year… ;sarc/ The Stupid, it burns…