Oblique origin lunar craters, where are they?

[nightvision]

Is there an explanation for the predominance of symmetrical craters on the moon? 

Is there a mechanism at work that ensures that most of the craters we see on the moon are near circular, pointing to perpendicular origins?   

Are there any non-circular craters on earth?

[nightvision]

BTW I understand that objects (like the one that caused the Tunguska blast) can arrive on an oblique path and still produce a near circular footprint but that type of event requires an atmosphere.

[vlaiv]

Quick search gave this:

http://curious.astro.cornell.edu/about-us/38-our-solar-system/the-earth/impacts/47-why-are-craters-round-beginner

Quite plausible explanation

[Zakalwe]

42 minutes ago, nightvision said:

Are there any non-circular craters on earth?

Yes...but due to the mechanics behind crater formation they are far outweighed by round craters.

https://the-moon.wikispaces.com/Oblique+Impact+Craters

 

[nightvision]

Thanks for the informative replies. 

Makes sense that the resulting explosion would overwhelm any directional/angular effects.

[Stub Mandrel]

Check out the pair of craters known as Messier A and B.

The ejecta pattern shows they were formed by two impacts of objects (or one object bouncing) coming in low from the right*

*As you look at the moon, obviously from top left of the photo, which I suspect is actually a triple impact.

[nightvision]

21 hours ago, Stub Mandrel said:

Check out the pair of craters known as Messier A and B.

The ejecta pattern shows they were formed by two impacts of objects (or one object bouncing) coming in low from the right*

*As you look at the moon, obviously from top left of the photo, which I suspect is actually a triple impact.

Nice find!

[Stub Mandrel]

3 hours ago, nightvision said:

Nice find!

It's a classic example, the photo is a NASA one, I think.

[laowhoo]

 

The Electric Universe hypothesis raises similar issues (among countless others), but this study directly addresses your question--a great one, BTW, even tho' people tend to abuse the expression (don't mind if I do)

http://www.impact-structures.com/understanding-the-impact-cratering-process-a-simple-approach/making-impacts-experimental-hypervelocity-crater-generation/