How Does Crater Rays Get Their Form and Shape?

The mystery of the crater rays pattern is finally solved. Learn how these rays are formed and how they get their unique shapes in this short article.

Have you ever wondered how Tycho crater got its rays and especially why they look like they do?

Blazing pieces of rock are continually blasting the planetary bodies of our solar system and are especially notable on our Moon, leaving behind long-lasting scars. 

These forms of craters can be used to learn about the history of our only satellite, the Moon, helping scientists feverishly study their lunar landscape features. 

However, one pattern commonly found around craters has remained a mystery. Sometimes, these Moon craters hold radial rays of debris fanned out around the Moon craters. 

In labs around the world, scientists have tried to replicate these ray patterns by dropping or shooting balls into containers full of sand or other materials like beads but still have found little success.

But in a recent study published on June 27th, 2018, in the journal Physical Review Letters, a team of scientists has eventually made some progress in explaining how crater rays form.

The picture is showing a spectacular impact crater and displays a system of rays in enhanced color. Credit: NASA/JPL-Caltech/Univ. of Arizona.
The picture shows a spectacular impact crater and a system of rays in enhanced color. Credit: NASA/JPL-Caltech/Univ. of Arizona.

What Do These Crater Patterns Following a Meteorite Impact Tell?

The scientists subsequently attained critical insights into how crater rays are formed. 

And the number of those rays depends on the ratio of the size of the ball to the size of the surface undulations. 

In terms of meteorite impacts, this is equivalent to the size of the meteorite compared to the space between valleys on the surface of the affected Moon or planet.

The Conclusions From The Experiments

So, if the surface is smooth, then the meteorite impact creates a similarly smooth shockwave that scatters the ejected grains evenly, and no rays are produced. 

However, with an uneven surface, this shockwave becomes asymmetrical, causing the ejecta to clump in some areas and form rays that eject out from the meteorite’s impact zone. 

Especially the crater rays form where the ball intersects with the edge of a slope in the surface, like in the case of our Moon, the rim of a crater.

If you want to learn more about how to view the Moon from a telescope or a pair of binoculars, then head over to this interesting article: How To See The Moon: Best Telescope Viewing Tips.


Picture showing Tycho and Copernicus Lunar Ray Craters.
Credit: Steve Mandel, Hidden Valley Observatory.
Picture showing Tycho and Copernicus Lunar Ray Craters.
Credit: Steve Mandel, Hidden Valley Observatory.

Well, that’s it. Thanks for reading. I hope you enjoyed this short article. And if you are interested in our Moon and especially Tycho crater, then take a look at this fascinating article: Moon Crater Tycho. You will find everything there is to know about this amazing Moon crater. 


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