You couldn't want to blast and create a debris field.
If its so large a rock in space it will destroy all life on earth that's one matter.
Quote from: Prober on 02/21/2013 02:48 pmIf its so large a rock in space it will destroy all life on earth that's one matter.This planet has been bombarded by objects of different sizes for billions of years. Life is still here. Humans, that's a different matter...
Not entirely true, actually.
Quote from: Robotbeat on 02/19/2013 04:53 pmOr, how about a counter-orbiting impactor, giving a relative velocity of 60km/s, far beyond chemical explosives. Could be accelerated slowly using very high-Isp ion thrusters, then kept in an heliocentric orbit ready to be commanded to intercept. (You'd need several of these so you could intercept within a month of command.)I know that it's fun to speculate wildly, but there are some sources you could read out there about this. I've worked with the PI on the Deep Impact mission and he said that impacting that comet, which was 100 km wide, at 10 km/s, was very difficult to do. So trying to hit something even smaller at six times the relative velocity might be a little harder.
Or, how about a counter-orbiting impactor, giving a relative velocity of 60km/s, far beyond chemical explosives. Could be accelerated slowly using very high-Isp ion thrusters, then kept in an heliocentric orbit ready to be commanded to intercept. (You'd need several of these so you could intercept within a month of command.)
Quote from: Robotbeat on 02/21/2013 05:03 pmNot entirely true, actually.What's not entirely true? I said that life is still here. I think you'll find that is entirely true. The other point, that the impact of a Moon sized object could sterilize the Earth is probably true. But it obviously hasn't happened since life has arisen on this planet. The chance of that happening before the Sun becomes hot enough to destroy life on Earth is very small indeed. (There is apparently a few percent chance that the orbits of Mars or Mercury could become chaotic enough in four or five billions years time to cause planetary collisions.)We don't have to worry about collisions of that magnitude. Impacts of objects the size of the Chelyabinsk meteor and up to kilometers in scale, we do, of course, have to worry about.
Quote from: 360-180 on 02/21/2013 08:49 amQuote from: Hyperion5 on 02/21/2013 06:18 amFor awhile, I was wondering how Russians were staying so calm driving their cars while this meteor lit up the sky. Chelyabinsk guys in Russia have a reputation for the most harsh. Type in a search engine "Суровые челябинские мужики настолько суровые, что" means "Harsh Chelyabinsk men are so harsh that" "Harsh Chelyabinsk men are so harsh that the fish jammed (concussied) by meteorites" "Chelyabinsk residents are so severe that instead of snow in winter they are falling meteorites"excuse my poor EnglishA few I understood:Chelyabinsk guys are so tough, traffic cops bribe them.Chelyabinsk programmers are so tough that they thinkprogramming in assembler is a luxury -they manually magnetize hard disk sectors.Chelyabinsk vodka is so tough that it was banned as WMDin 190 countries.Chelyabinsk woodpeckers are so tough, they hollowed out2 metro stations.etc.
Quote from: Hyperion5 on 02/21/2013 06:18 amFor awhile, I was wondering how Russians were staying so calm driving their cars while this meteor lit up the sky. Chelyabinsk guys in Russia have a reputation for the most harsh. Type in a search engine "Суровые челябинские мужики настолько суровые, что" means "Harsh Chelyabinsk men are so harsh that" "Harsh Chelyabinsk men are so harsh that the fish jammed (concussied) by meteorites" "Chelyabinsk residents are so severe that instead of snow in winter they are falling meteorites"excuse my poor English
For awhile, I was wondering how Russians were staying so calm driving their cars while this meteor lit up the sky.
I was nitpicking.
Quote from: Robotbeat on 02/21/2013 05:03 pmNot entirely true, actually.What's not entirely true? I said that life is still here. I think you'll find that is entirely true.
It's true but misleading.According to orthodox theory, life as we understand it appeared in the Cambrian explosion ~400 million years ago. The heavy meteor bombardment stage of the solar system's history (when most of the Moon's craters were created, for example) occurred four billion years ago.There have also been several occasions where a very large meteoric event came close to eradicating all life on Earth. The infamous Yucatan Event is actually the smaller and less destructive of the two. The other one occurred in the Deveronian period, IIRC, and took out about 90% of all vertebrate life.
As best as I can tell from a few quick searches, the [Permian-Triassic ] event's cause is still not quite pinned down, and it might have been a combination of too many stressors ranging from supervolcanism to an impact.
The oldest microfossils go back to about 3.5 billion years ago, so prokaryotic life (cells without nuclei) was abundant by then.The largest mass extinction known from the fossil record, which you mentioned, is the Permian-Triassic event, about 250 million years ago. Marine life was almost wiped out, over 90% killed, and about 70% of land species as well. As best as I can tell from a few quick searches, the P/T event's cause is still not quite pinned down, and it might have been a combination of too many stressors ranging from supervolcanism to an impact.Jeff
It's true but misleading.
ProjectB612: If the dinosaurs had a space program, they'd still be here.Fornaro: If the dinosaurs had fiscal restraint, they'd still be here.
The largest mass extinction known from the fossil record, which you mentioned, is the Permian-Triassic event, about 250 million years ago. Marine life was almost wiped out, over 90% killed, and about 70% of land species as well. As best as I can tell from a few quick searches, the P/T event's cause is still not quite pinned down, and it might have been a combination of too many stressors ranging from supervolcanism to an impact.
Some guys figure the Permian/Triassic extinction was due to the the impact in Antarctica, which left a 500 km diameter crater. Ever driven 500 kilometers? That's a big impact. http://www.bbc.co.uk/nature/extinction_events