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Space rock 'on collision course' with Earth!!!

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  • Did a quick check, Antartica has an ice covered area of 13 million square km. The three main oceans 300 million square km. That would mean Antartic ice would have to be 6,500 ft thick, on average, to cause a 300ft rise in sea levels.
    One day Canada will rule the world, and then we'll all be sorry.

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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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      • 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.



        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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        • India could use less population anyway


          Ugh. Not a very nice sentiment...
          12-17-10 Mohamed Bouazizi NEVER FORGET
          Stadtluft Macht Frei
          Killing it is the new killing it
          Ultima Ratio Regum

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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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            • I don't doubt it, but I would think that a 2000 meter path through ice would do a lot toward lessening final impact on dirt/rock...
              12-17-10 Mohamed Bouazizi NEVER FORGET
              Stadtluft Macht Frei
              Killing it is the new killing it
              Ultima Ratio Regum

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              • Well if it's "just" 2 km in diameter than a nuke should mess it up fairly well.
                "I say shoot'em all and let God sort it out in the end!

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                • Not really...
                  12-17-10 Mohamed Bouazizi NEVER FORGET
                  Stadtluft Macht Frei
                  Killing it is the new killing it
                  Ultima Ratio Regum

                  Comment


                  • 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).
                    12-17-10 Mohamed Bouazizi NEVER FORGET
                    Stadtluft Macht Frei
                    Killing it is the new killing it
                    Ultima Ratio Regum

                    Comment


                    • 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
                      "I may not agree with what you have to say, but I'll die defending your right to say it." — Voltaire

                      "Wheresoever you go, go with all your heart." — Confucius

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                      • 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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                        • 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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                          • Because the waves rushing around the earth in all directions would reach the antipodes at pretty close to the same time...theoretically all the energy in S-waves would be coincident there a few hours(?) after initial impact. Dampening would make situation better there than 500 km from impact site, say, but possibly worse than in other places (a few thousand km away).
                            12-17-10 Mohamed Bouazizi NEVER FORGET
                            Stadtluft Macht Frei
                            Killing it is the new killing it
                            Ultima Ratio Regum

                            Comment


                            • 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.
                              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.

                              Geology is partly detective work, and scientists now have enough evidence to book a suspect in the greatest mass extinction on Earth. Volcanic eruptions called the Siberian Traps released gases that pelted the planet with acid rain, toxic metals and destr


                              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:



                              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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                              • Originally posted by Sagacious Dolphin
                                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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