Calculating Radius of Crater from Meteor Impact

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Discussion Overview

The discussion revolves around the calculation of the radius of a crater formed by a meteor impact on Earth. Participants explore the dynamics of impact, including factors such as mass, velocity, and ground type, as well as the relationship between kinetic energy and crater size.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether a dynamical method exists to calculate the shape and radius of a crater from a meteor impact, given specific parameters like mass and velocity.
  • Another participant suggests starting with the calculation of kinetic energy, noting that this energy will dissipate upon impact and that the relationship between kinetic energy and crater size is likely non-linear.
  • A participant seeks clarification on the nature of the impact, questioning whether it is a glancing impact and correcting a potential misunderstanding about the size of the meteor relative to Earth's diameter.
  • One participant emphasizes the importance of ground type on crater size, indicating that solid rock would produce a smaller crater compared to soft ground for the same meteor size.
  • There is a discussion about the type of meteor and its velocity at impact, with a participant suggesting that the initial velocity provided (200 km/s) is unusually high compared to typical meteor speeds.
  • A reference to the Barringer Crater is made, providing an example of a meteor's size and impact velocity, along with the resulting crater diameter.

Areas of Agreement / Disagreement

Participants express differing views on the factors influencing crater size and the methods for calculating it. There is no consensus on a definitive approach or formula for determining the radius of a crater from a meteor impact.

Contextual Notes

Participants note various assumptions, such as the type of ground and meteor, as well as the initial velocity of the meteor, which may affect the calculations and outcomes discussed.

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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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 dissipated 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.
 
ChrisVer said:
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?
 
oops...I wrote horizontally, I meant vertically (like a falling apple)
 
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 let's 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 traveling 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
 
Last edited:

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