what is meant by bomb radius? is it the size of the crater itself or the area across which debris would fall?
467874
It is how far the bomb blasts.\n\nAn example of usage:\n\n"Any enemy within the bomb's radius at the time of blast will be killed"
68067
Fifty-seven people were killed and 200 homes, 47 bridges, 15 miles (24 km) of railways and 185 miles (300 km) of highway were destroyed. The eruption caused a massive debris avalanche, reducing its summit from 9,677 feet (2,950 m) to 8,364 feet (2,550 m) in elevation and replacing it with a mile-wide (1.5 km-wide) horseshoe-shaped crater (see geology section or 1980 eruption of Mount St. Helens for more detail). The debris avalanche from the 1980 eruption was up to 2.3 cubic kilometers (0.7 cubic miles)in volume, making it the largest in recorded history. However, the scale of it still pales in comparison to far larger debris avalanches that have occurred in the geological past elsewhere on Earth.
802234
There's this nuclear hand grenade, see?  It can create a crater 100 yds by 80 yds, see?  Only problem is that the average soldier can only throw a grenade 40 yds.\n\nBut, see: http://en.wikipedia.org/wiki/W79  Anything smaller is rather pointless, since the amount of fallout and other effects makes using a conventional weapon more appropriate.
157349
There was a mysterious explosion.  The explosion was extreamly powerful (on the scale of atomic bombs I believe), flatting trees all around.  But it wasnt for a number of years that people were able to get up there and try find out what happened.\n\nIt possible could have been a meteor explosion right before it hit the ground, but there is no other evidence to support this.  I dont think we really know what happened, but the meteor idea is pretty likely I think.
408598
probably mushroom . . . the shape of a cloud after a nuclear bomb
1008853
Depends how you define seismic activity.  \n\nYes, the intensity as measured by seismometers would be strongest at the epicenter.  This does not mean the damage would be greatest directly over the epicenter, on in the nearest town.
721740
***Assuming the same amount of kinetic energy in both objects (roughly the same mass and velocity)*** the asteroid will do more damage. Look to Shoemaker-Levy 9 to understand why.  \n\nModels predicted (and were borne out by observations) the the fluffy stuff comets are made of will start to spread out as it decelereates, resulting in increasing drag, causing more deceleration and more spreading, and by the time it reaches about 1 earth atmosphere worth of air will essentially splatter like a snowball on cement. (I once calculated the tidal forces that disrupted SL-9, and came to the conculsion that they have about the same cohesion as cigarette ash!) SL-9 did exactly these.  Splattered all over the top of Jupiter's atmosphere making spots thousands of miles across that then disappated over the next several days.\n\n\nCheck out\nhttp://antwrp.gsfc.nasa.gov/apod/ap001105.html\nand\nhttp://www2.jpl.nasa.gov/sl9/\n\nThe comet would make a loud boom that would literally be heard around the world, and probably cause a massive fire right beneath, but a large fraction of the energy would be dissipated as sound.\n\nA denser mass will plow straight through the atmosphere and deposit almost all of its kinetic energy in the crust of the earth.  Many times its own mass will be hurled into the air as debris, much of it superheated, and come raining down over a large chunk of the earth, and at the same time deposit a great deal more dust in the atmosphere impacting climate more and longer.
218083
I assume you mean nuclear "bomb"...\n\nIn simplistic terms, and nothing you can't easily find elsewhere, a nuclear bomb is made up of material that fissions (meaning that its atoms can be split to release energy) - this is either Uranium-325 or Plutonium.  Uranium is found in nature but the vast majority is U-238 which doesn't fission - natural uranium must be enriched to create a fissionable amount of uranium - this is true for commercial power reactor fuel too.   Plutonium is made in nuclear reactors from bombarding other materials with neutrons.\n\nTo have a "nuclear yield" the fissionable material in a bomb must be forced into a 'critical mass' configuration which means that it is so dense (atoms close together) that once the material starts to fission and release energy and neutrons, other atoms will capture the released neutons and then they will fission releasing more energy and neutrons and so on and so on with the chain reaction making the boom.\n\nWith the early plutonium bombs (Fat Man), the material was in a sphere and was forced together with high explosives uniformly to create a ball (critical mass). In the first uranium bomb (Little Boy, which they didn't even test until it was dropped on Japan since they were confident it would work) 2 uranium blobs were forced together by essentially thrusting/throwing/shooting one to the other to create the critical mass.  The math behind all this physics is incredibly complex.\n\nTo add bang for the buck they started adding the gas Tritium, an isotope of hydrogen, hence the name Hydrogen bomb versus just the Atomic Bomb...  Tritium makes the yield much bigger.
271223
Nuclear weapons have been made anywhere from a few kilotons in yield to 20 Megatons and up.\n\nIt's damage will depend upon where it is detonated or how high it is detonated above the ground.  If one is detonated at ground level the damage will not spread as far as one that was detonated above ground level.\n\nCheck out the Federation of American Scientests Website.
48717
From Wikipedia.org:\n\n" Fifty-seven people were killed and 250 homes, 47 bridges, 15 miles (24 km) of railways and 185 miles (300 km) of highway were destroyed. The eruption caused a massive debris avalanche, reducing its summit from 9,677 feet (2,950 m) to 8,364 feet (2,550 m) in elevation and replacing it with a mile-wide (1.5 km-wide) horseshoe-shaped crater (see geology section or 1980 eruption of Mount St. Helens for more detail). The debris avalanche from the 1980 eruption was up to 0.7 cubic miles (2.3 km3) in volume, making it the largest in recorded history. However, the scale of it still pales in comparison to far larger debris avalanches that have occurred in the geological past elsewhere on Earth."
408657
It depends on four things:\n\n1. Size of the bomb's yield (measured in megatons)\n2. The type of bomb (atomic, hydrogen, etc.)\n3. The terrain around where the bomb detonates (mountains or desert, etc.)\n4. The elevation of the bomb at detonation (some of them are set to explode ABOVE the terrain).\n\nBut, to give you a typical example:\nCommon single MIRV warhead (thermonuclear type bomb that is 10 Megatons, which is equivalent to 10 thousand tons of TNT), exploding 2000 feet over a desert with low rolling hills would have these ranges, in the order in which an instrument would first measure it:\n\n1. XRAY and Gamma Ray effect: 1000 mile diameter. Causes almost all electrical appliances to stop.\n2. Heat from the light: 50 mile diameter\n3. Permanent blindness from the light: 20 miles\n4. 3rd degree skin burns: 18 miles. 2nd degree: 16 miles. 1st degree: 15 miles.\n5. Killed/Bents/Destroyed biological material (animals, Humans and foliage): 12 miles.\n6. Vaporized biological material (animals, Humans and foliage): 10 miles\n7. Vaporized concrete up to 4 feet thick: 5.5 miles.\n8. Physical crater in the Earth, caused by all this: 1 mile in diameter and about 100 feet deep.\n\nThen AFTER the blast: \n- Nuclear radiation "Hot Zone" death in 24-48 hours would be about 25 miles.\n- Nuclear radiation "Hot Zone" sick or die in 30 days would be about 100 miles.\n- Also: Nuclear fallout - up to thousands of miles downwind.\n- Uninhabitable for about 250 years within 50 miles.\n\nHope this helps.\n\nIf this is the best answer, please vote it the best answer. Thanks!
37488
An atomic bomb is composed of some heavy-duty explosives, U-235 or P-239, and a neutron source.\n\nThe neutron source is in the center, surrounded by the Uranium or Plutonium, and then the explosives. Upon detonation, the explosives explode simultaneously, crushing the nuclear material in on the neutron source. This causes the material to achieve critical mass and a massive chain reaction takes place. Very massive.
1035178
If I'm not mistaken, we've tested a number of 20-megaton nukes before, and the fact that you're able to ask this question means that we've survived that first test. :-)  \n\nAs for how big of a nuke it would take to blow up Earth, a couple of issues you'll have to deal with first is what to do about all of the debris that will settle after the nuke goes off, because as it floats back down because of gravity, then gravity itself will hold down all of the matter upon Earth. As to what it would take to cause the most damage, I've gotten to thinking since the 2004 tsunami that if a well-placed nuke was right on major fault lines either in the ocean or possibly on land (like maybe on the New Madrid fault), the tectonic action resulting from the force of the nuclear blast would be much more destructive than the bomb itself, because the shifting of tectonic plates would then cause damage at a much greater radius from ground zero in the resulting earthquake than would just blast waves in an atmospheric explosion.\n\nMaybe that doesn't answer your question, but it's the best I can figure as I am neither a physicist nor a geologist. :-)
257364
When an atomic bomb detonates, a nuclear fission reaction occurs which actually transforms a very small amount of mass into energy.\nUsing the well-known formula,\nE=mc^2,\nwe can calculate the amount of energy associated with that mass that is "lost".\n\nOnly a very very tiny amount of mass is actually trasformed into energy in the reaction, but since that mass is multiplied by such a huge number (the speed of light squared), the energy released is gigantic.\n\nUsually, A-bomb yeilds are given in terms of [kilo / mega] tons of TNT to measure the energy given off.\nThe yeild on the atomic bomb detonated over Hiroshima Japan in 1945 ('Little Boy') was about 16 kilotons of TNT [high end estimate].  1 ton of TNT releases about 4.25 E9 Joules of energy.  Using this conversion, we can calculate that the Hiroshima bomb released about 6.8 E13 Joules.  By comparison, the entire average enegry consumption of the United States per year is on the order of 10 to the 20 Joules, so 1 A-bomb packs a pretty good punch.\n\nSince 1945, atomic bombs have gotton much MUCH more powerful in addition to the Hydrogen bomb which is exceedingly more powerful than the atomic bomb.
494420
A small explosive that when thrown down hard against a hard surface explodes. The explosion is loud but mainly harmless like a cap.
797644
Impact crater characteristics to look for:\nShocked minerals\noverturned bedding in ejecta blanket\ncircular shape (nearly always)\nlow rim relief over surrounding areas\nbottom of crater lower than surrounding plain\n\nVolcanic crater characteristics:\nlooks like a mountain (high rim relief)\nvolcanic materials present\ndoes not have to be circular \noften multiple craters within caldera  \nbottom of crater higher than surrounding plane\nno shocked minerals
52366
Estimates of about 35 million pieces of debris are common.  Of these about 100,000 are in the square centimeter or larger size category, and NASA routinely tracks about 8,000.  People are good at throwing stuff away.  Shame we did not throw ot far enough away.\nI have personally viewed at least four or five of the biggest pieces.