Why are craters round?
Why do all impact craters appear round as if they all come from strikes that are perpendicular to the surface of the impacted surface?
Shouldn't there be a mix of a few round and many different oval shapes to account for all of the strikes that are glancing blows instead of direct hits? It seems there should be many more indirect hits that produce oval impact craters rather than perfect perpendicular hits which make perfect impact circles. Thanks!
The short answer is that the energy involved in an impact is so huge that when the impactor hits the ground, it explodes like a bomb, rather than just denting the surface like a rock thrown into mud. Explosions are generally symmetric, so the resulting crater from most impacts is circular. Only very very shallow impacts form elliptical craters, but they do exist!
A more extensive answer to this question can be found at Scientific American.
Here is an interesting Planetary Society blog entry about a nice example of an elliptical crater on Mars.
Get More 'Curious?' with Our New PODCAST:
- Podcast? Subscribe? Tell me about the Ask an Astronomer Podcast
- Subscribe to our Podcast | Listen to our current Episode
- Cool! But I can't now. Send me a quick reminder now for later.
How to ask a question:
If you have a follow-up question concerning the above subject, submit it here. If you have a question about another area of astronomy, find the topic you're interested in from the archive on our site menu, or go here for help.Table 'curious.Referrers' doesn't existTable 'curious.Referrers' doesn't exist
This page has been accessed 14420 times since July 22, 2007.
Last modified: July 22, 2007 5:58:39 PM
Ask an Astronomer is hosted by the Astronomy Department at Cornell University and is produced with PHP and MySQL.
Warning: Your browser is misbehaving! This page might look ugly. (Details)