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Ethelred
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Not if the rock hits limestone it won't.
What if it hits one of the volcanoes? There is at least one that is actually under kilometers of ice. Its active too. That one I am not using as an example of what could be a bad target. I am just curious about what would happen if a bolide hit an active volcano or especially a hot spot like Hawaii or Yellowstone.
Smack dab in the middle of the Steppes of Russian sounds good for a land strike.
Pacific is probably a good place except for people living on the Ring of Fire. Like me for instance, in Anaheim.
The Atlantic would be best except for all those coastal cities.
I got one. The ocean everyone forgets about. The Indian Ocean. Its all abyssal plain. Nothing but basalt and sea sediments. Maybe not even even much in the way of methane hydrates to vaporize. India could use less population anyway. OK so the Australians would lose Perth, most of them live on the opposite coast and might miss the tsunamis.
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Ethelred
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quote:
Originally posted by Sagacious Dolphin
That would mean Antartic ice would have to be 6,500 ft thick, on average, to cause a 300ft rise in sea levels. |
Guess what? Its over that in most of it. A lot over it in a few places.
http://www.botany.uwc.ac.za/Envfact.../antarctica.htm
Antarctica covers about 14-million square kilometres, or 10% of the earth's land surface. A permanent ice cap covers 98% of the land, with an average depth of 2 km and a maximum depth of 4,5 km. The main ice-free areas are around the coast, but in many places the icecap extends off shore in vast ice shelves. About 90% of the world's fresh water is stored in this icecap and if it were to melt the world's sea level could rise by an estimated 55 metres.
OK its not 200 feet. Its 180 feet.
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Ethelred
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No its not nice. Its just reality.
I think birth control is a much better answer. They MUST do something soon or there will be a serious disaster of some kind. They are on the edge allready. Even China has better food production and at least they are trying to deal with their population problem.
Ugh no I don't care to do that math. If I was good at math I would be one of the physicists in this conversation but I am not.
23 KM/S is reletively good actually. Well at least I thought the average was around 40 KM/S for asteroids hitting the Earth. Thats a heck of a lot less energy being released than if it was at that average speed.
I am thinking more of long term global warming from an impact on the wrong kind of land than the heat released directly by impact. Much of that would go into space and in vaporizing rock. If the impact was on silicate rock that would be the best for long term effects after the water. Water would absorb a lot of the energy though and that is better than anything else that it could hit. However ANY place it would hit it would also include its hitting rock. Unless it broke up into small enough chunks.
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Dr Strangelove
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Well if it's "just" 2 km in diameter than a nuke should mess it up fairly well.
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ravagon
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Australia
Sep 1999
time: 13:21
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quote:
Originally posted by Frogger
Nukes don't gouge out 2 km craters, I don't see why you'd expect one to break up an object of similar size (if solid). |
If you're thinking of vaporizing it completely then a standard low-megaton yield fusion warhead wouldn't do it.
Breaking it up though is a different matter entirely. As well as reducing it by a small margin the shock waves transmitted through an object that small would have severe structural consequences - especially to an object formed in zero-G and having spent its lifetime under bombardment by cosmic micro-meteorites anyway.
If the body was formed as some sort of ejecta from a dense-iron planetary body (Io for example) then it might not be so easily damaged ...
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ravagon
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Australia
Sep 1999
time: 13:21
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quote:
Originally posted by Gatekeeper
It seems like I remember seeing something about the impact 65,000,000 years ago: While the meteor itself hit in what is now Central America, the shockwaves (which went straight through the planet) were so intense that it generated horrifyingly powerful volcanic and seismic disturbances on the surface of the planet *opposite* the impact point. IOW, whatever land/water/flora/fauna was where India is now had a very bad time of it all.
So if the 1.2 mile/2 km asteroid hit in Antarctica, Australia or the South Pacific, would there be a similar effect? Or would the meteor be too small? After all, it would lose some of its mass approaching Earth and once it entered the atmosphere.
Gatekeeper |
The asteroid in question isn't nearly massive enough to have that kind of global effect. The impact would have to trigger some form of chain reaction in the inter-linking system of tectonic plates to produce an effect on that order of magnitude. ie: It'd have to hit in just the right spot. San Andreas maybe ... ? Or elsewhere in the Pacific rim of fire?
I've never heard of such an effect on the opposite point on the Earths surface though. Seismic waves are attenuated close to the surface and partially blocked/refracted by the core-mantle interface so I'm not sure how an opposite point on the surface would be affected more than other points closer to the impact.
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Ethelred
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quote:
Originally posted by Gatekeeper
It seems like I remember seeing something about the impact 65,000,000 years ago: While the meteor itself hit in what is now Central America, the shockwaves (which went straight through the planet) were so intense that it generated horrifyingly powerful volcanic and seismic disturbances on the surface of the planet *opposite* the impact point. IOW, whatever land/water/flora/fauna was where India is now had a very bad time of it all.
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Those are the Deccan Traps. There is an even larger but similar formation called the Siberian Trapps that may be associated with the Permian mass extinction in which 90% of the Earth's species went extinct. The Deccan Trapps may have allready started when the KT event occured. It went on for about 10 million years and was long considered as a possible cause of the mass extinction.
The position is very interesting. It does imply that the impact might have been the trigger. The Siberian Traps is the only thing I am aware of that is similar and it too may be associated with an ancient impact on the opposite side of the world. However those are the only two so its not likely that this bolide is large enough and fast enough to cause something similar or there would be a lot more such lava formations if indeed an impact triggered them.
http://www.space.com/scienceastrono...ian_000907.html
Then again the Siberian Trapps may have been cause by a direct impact rather than a atipodal one. Just saw this site a bit more than halfway down the page:
http://www4.tpg.com.au/users/tps-se...pacts_volcanoes
Interesting anyway. It says the Hawian Islands are the same hot spot as caused the Siberian Traps and that the high iridium content of howaian lava my be from the remains of an asteroid that punched through the crust all the way to the mantle. Its a space site so don't bet on geologists jumping onto this idea real quick. Took a long time for them to forgive the two Drs. Alvarez(father and son) for not being a pair of geologists regarding the KT impact.
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Capt Dizle
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quote:
Originally posted by Sagacious Dolphin
quote:
The question then becomes whether or not the spaceflight alone was worth the additional cost... |
That is why I mentioned 'prohibitive' costs. Implicit that the spaceflight was not worth that much. Hence I think the Apollo programme was an unwarranted scientific expense as it is too expensive to capitalise on the Moon landings.. |
Really bad thinking. Great scientific advances go hand in hand with great endeavors. Such as war. The Apollo program was simply an extension of the Cold War. The benefits were immense.
As for the issue of expense, you need to zoom out and view the forest. Every cent spent is simply recycled into the economy and none is wasted and the only thing that is ever lost is the irreplacable resource and those can only become replacable when we venture into space.
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Capt Dizle
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In what way is the labour supply finite?
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Capt Dizle
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You would be right if there were a finite number of days for the species, which will be true only if we remain Earthbound.
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Capt Dizle
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There are a lot of things the US government funds with tax dollars as useless as digging and refilling holes. In the big scheme of things. Don't you realize that someone would earn their living diggin?
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Ethelred
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Well that was offtopic. However some alleged makework does have value. It is possible to hire people to do things that need to be done but no one wanted to pay for before. Like improveing national parks for instance. Little of direct economic value but it still has cultural value.
Digging holes and then filling them in again does not fit that kind of value either. It would a be silly thing to have people doing for a living when there are so many usefull things that the private sector can't or won't do because there isn't enough profit in it.
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Capt Dizle
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I am quite sure I was not trying to explain Keynesian economics.
Isn't it arrogant for you to decide what someone is trying to explain, and then label them inept at doing it?
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Capt Dizle
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You must consider yourself educated as well as socialist.
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28-07-2002 07:36
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