It was already known that we were totally doomed, but now there is a new and exciting scenario. In this one, comets rain down on us from the Ooort Cloud, said comets loosened by contact and interaction with a star called Gliese 710.
Gliese 710 is one of a handful of stars that have had recent interactions with our solar system, or plan to in the future.
there is 86 percent chance that Gliese 710 will plough through the Oort Cloud of frozen stuff that extends some 0.5 parsecs into space.That may sound like a graze but it is likely to have serious consequences. Such an approach would send an almighty shower of comets into the Solar System which will force us to keep our heads down for a while. And a probability of 86 percent is about as close to certainty as this kind of data can get.
The good news is that Bobylev says the chances of Gliese 710 penetrating further into the Solar System, inside the Kuiper Belt, are much smaller, just 1 in a 1000. So that's all right, then.
Physical Science
Comments
...in the next million and a half years. I think I'll keep my head up for a while.
Posted by: Stephanie Z | March 14, 2010 3:17 PM
I will hide behind Rush Limbaugh, he has a hugely inflated ego that will protect me from comets.
Beside, I can't feel threatened by something called the Oort cloud (only 2 letter Oh's).
Posted by: NewEnglandBob | March 14, 2010 3:20 PM
Doesn't an Oort cloud have something to do with the Swedish Chef?
Posted by: Uncle Glenny | March 14, 2010 3:27 PM
Doesn't an Oort cloud have something to do with the Swedish Chef?
No.
Posted by: The Swede | March 14, 2010 4:00 PM
That reminds me of those theories 15 or 20 years ago that the sun actually had a very faint, distant companion star orbiting way out beyond the main part of the solar system, and that it periodically went through the Oort cloud and sent a swarm of comets down into the inner solar system. I'm pretty sure that theory was pretty much rejected, since with the kind of surveys they have done by now, it would be almost impossible to miss even the faintest red dwarf that was less than 1 light year away.
I think the Oort cloud was actually named after a Dutch guy.
Posted by: Paul S. | March 14, 2010 4:09 PM
I seem to recall a story from Physorg.com a week or two ago, stating that the Oort cloud may actually contain fewer comets than assumed. The old count was derived from the number of a specific class of comets, but the assumptions behind the estimate was challenged in the story....
My point is, even though I hate to disappoint those who look forward to Armageddon, this new threat is unlikely to deliver, even if you plan to live two million years.
Posted by: Birger Johansson | March 14, 2010 4:15 PM
@Paul S: unfortunately not: http://www.telegraph.co.uk/science/space/7429335/Search-on-for-Death-Star-that-throws-out-deadly-comets.html
Posted by: Deen | March 14, 2010 4:17 PM
Actually this will be a good opportunity (provided it doesn't come too close to the Sun, close enough to disrupt the orbits of things inside Jupiter's orbit).
A shower of comets coming into the inner solar system will be an oportunity to put them into capture orbits around Earth, Mars and Venus.
Mars will then be pretty easy to terraform, Venus somewhat more difficult. The limiting factor on Venus is getting enough hydrogen to provide enought water. The CO2 atmosphere can be pumped underground. Once Venus cools and has enough water, the CO2 will be trapped as carbonates.
Posted by: daedalus2u | March 14, 2010 4:19 PM
@Paul S.: Oort cloud is named after Jan Oort - he was Dutch.
Posted by: MadScientist | March 14, 2010 4:55 PM
Well the Gliese 710 encounter has been known for a while, and the miss distances estimated there don't seem too far off the values previously quoted.
In terms of how much this will perturb the Oort cloud, the last event of comparable severity was the Algol triple system passing at a distance of roughly 2.4 parsecs about 7 million years ago. The larger distance compared to Gliese 710 is compensated by the higher mass of the Algol system (totalling about 6 solar masses, as opposed to 0.5 solar masses for Gliese 710) and the longer duration of the encounter.
Given life on Earth is still here, it is fairly obvious that the passage of the Algol system didn't wipe out everything in a blaze of cometary fury.
Posted by: andy | March 14, 2010 5:08 PM
Andy, you may be half right and half wrong. These are new numbers based on a new study that is not entirely contradictory to the older studies, but is different. One of those differences contradicts your assertion that the last close call would have been 7.5 mya. Check back through the link for that, I'm not following the details myself that closely.
Posted by: Greg Laden | March 14, 2010 5:22 PM
Guess I picked the wrong geologic epoch to quit sniffing glue.
Posted by: Douglas Watts | March 14, 2010 6:32 PM
Tell Al Gore. He will find a new pastime.
Posted by: VRWC | March 14, 2010 6:38 PM
If is doesn't happen in 2012 then it must be a hoax.
Posted by: Somnolent Aphid | March 14, 2010 8:53 PM
Greg Laden: sure I am not disagreeing that some stars have come a lot closer than Algol did in the past 7 million years, the question is how much they would perturb the Oort cloud. Most of the "close calls" are from low-mass stars that didn't hang around very long, unlike the slow-moving and massive Algol system.
Unfortunately the paper does not appear to calculate relative sizes of perturbations, but the encounter parameters do not seem to differ too much from this one - it is striking to see how much more significant the Algol encounter is compared to closer but faster and less massive stars.
Posted by: andy | March 15, 2010 12:07 PM
I don't have any real numbers, but shouldn't the orbital perturbations be because of the tidal effect. This should scale as the derivative of the gravitational force, which would imply an inverse R cubed effect. Five to the third overwhelms the factor of ten mass ratio. But of course the length of the encounter matters as well. I suspect that an encounter whose characteristic time is longer than the orbital period of cloud objects wouldn't be very effective as it the tidal acelerations on a given object could then cancel out. So perhaps these far encounters might not be all that effective.
But, there must have been some who did research projects on the issue, so it ought to be answerable.
Posted by: Omega Centauri | March 15, 2010 6:34 PM