# Crater shapes

Gold Member
When a stellar object falls into the earth's surface, it creates a crater on the ground.
Most of the times, when people refer to these things, they refer to their age and their diameter/radius. My question is mainly about the radius. Is there a dynamical way to solve for the shape and radius of a crater such an impact can cause?
Eg if I said that a meteor of mass 0.001 the mass of the earth, and initial velocity of 200 km/s falls horizontally on the ground, would I be able to calculate the radius of the crater?

## Answers and Replies

256bits
Gold Member
Well, you know the mass and the velocity, so you can start by calculating the kinetic energy of the steller object. This energy will have to be disipated upon impact ( upon impact there is a horizontal and vertical component to the velocity of the object ). The heat produced will liquify and/or vaporizie some, or all of the object and some of the earth. Correlation between the initial kinetic energy and size of the crater produced most likely does not follow in a linear fashion.

Bystander
Science Advisor
Homework Helper
Gold Member
falls horizontally on the ground, would I be able to calculate the radius of the crater?
You're wanting to model a glancing/grazing impact? Of an object a tenth of earth's diameter? Trajectory of COM is tangent to earth's surface? Cuts a chord 0.1 earth radii below the surface, passes 0.1 radii above the surface?
You might have meant .001 earth diameter?

Gold Member
oops...I wrote horizontally, I meant vertically (like a falling apple)

davenn
Science Advisor
Gold Member
2021 Award
The ground type at the impact site would also have an effect on the crater size produced
solid rock is likely to produce a smaller crater than soft ground for a given size meteorite impact
Also the type of meteor .... nickel/iron or rocky ( chondrite) and its velocity at impact

also lets get you velocity into a better range ---- 10 - 70km/s is the avg range for meteors entering the atmosphere
your 200 km/s is a bit high

its estimated that the meteor that produced the Barringer Crater in Arizona was still travelling at ~ 11 km/s when it impacted
This was a ~ 50 metre diameter nickel/iron type and produced a crater of about 1.2 km in diameter

Dave

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