Crater shapes

  • Thread starter ChrisVer
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  • #1
ChrisVer
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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?
 

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  • #2
256bits
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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.
 
  • #3
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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?
 
  • #5
ChrisVer
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oops...I wrote horizontally, I meant vertically (like a falling apple)
 
  • #6
davenn
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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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