If a 50 meter asteroid caused a 1.5 kilometer crater as Barringer Crater is described, how different would the impact of a 50 meter comet be, assuming the comet was 85% water and other volatiles, with the solid parts being mostly dust with a pile of gravel or a relatively small solid core? How much of the volatiles would be boiled off on impact with the atmosphere? Would it be enough to distribute the aftermath over a wider area, or would the comet remain basically intact and hit the Earth as an essentially solid mass? Consider also what effect steam explosions at or near the surface of the comet would have, or if a crack in the comet allowed a steam explosion to penetrate deep within it. Would the volatiles boiling off keep the solid matter cool enough so it would survive the fall to the ground? How fast would the meteorites be going if they did hit the ground? Would it perhaps look like an extremely intense meteor shower shortly followed by a scalding deluge? Would a larger area be affected by a solid impact or a cometary one?

So many questions, and "there's more at the door..."

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    $\begingroup$ That's a really interesting question. Do you have a specific reason to ask for "same diameter" and not "same mass"? I guess, the density of an asteroid might be significantly higher than that of a comet. $\endgroup$
    – TrySCE2AUX
    Oct 26, 2022 at 10:29
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    $\begingroup$ The first guess would be a Tunguska like impact, but on a slightly smaller scale. I can bet that a comet would have lower density, but higher speed and kinetic energy. Difficult to make a comparison. $\endgroup$
    – FluidCode
    Oct 26, 2022 at 11:44
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    $\begingroup$ @TrySCE2AUX Same diameter was what I thought of first. Same mass vs. same diameter adds another dimension to the range of possibilities - I like it :) $\endgroup$ Oct 26, 2022 at 15:56

1 Answer 1


An iron meteor surviving the trip through the atmosphere would loose a huge amount of kinetic energy onto its impact point resulting in well ... a crater. Effects are much more localized.

An icey comet has tons of matter behind it and a shockwave ahead of it. In between would be superheated steam looking for a way out. What usually happens is, like an overheated steam boiler, at some point it explodes. The effects, like at Tunguska, are more widespread with little or no material reaching the ground.


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