Orbits from impacts

  • Thread starter MarkL
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  • #1
MarkL
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After an impact, can a projection from the surface of a spinning planet obtain an orbit? I tried a three body simulation, but a two body works just fine.
"Newton cannon" is one Earth radius above the surface with different vt's. These are the types of orbits I am looking for.
"projected up" starts on the surface with a radial velocity, vr. At one Earth radii above the surface, I assumed the spin of the Earth would create the orbits seen in "Newton cannon", but it does not. It always falls back to earth.

is this the way it works? Thanks
 

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Answers and Replies

  • #2
berkeman
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There is an interesting discussion about this in the meteorite collection thread by @davenn

:smile:
Melt breccias come from all 3 known sources of meteorites, Lunar, Martian and the asteroids and are caused by impacts... asteroid - asteroid and asteroid to Moon or Mars
Ahhhh let me dig for a reference, am sure one was possibly found on the Moon.

here we go ...
https://eos.org/articles/apollo-may-have-found-an-earth-meteorite-on-the-moon

But of course, it won't have a fusion crust as the moon has no significant atmosphere

Now there are Earth rocks that have been melted and blasted into the high Earth atmosphere
or just out of it and have come back down to Earth. These produce tektites.
And, as you say, there is evidence of a very ancient Earth meteorite on the moon.
 
  • #3
MarkL
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Well, that last statement makes some sense, since the last I heard, the Earth and moon are found to be chemically similar. This is why the Giant Impact theory was later modified...right. To recap the origin of the moon:
1) giant impact into early earth.
a) impactor (s) is similar chemically to earth, or
b) impactor is made of ice...ice then melts leaving no trace
2) Portion if Earth gets thrown into orbit and forms a ring
3) ring coalesces into moon...voila!
sound right?
 
  • #4
davenn
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Well, that last statement makes some sense, since the last I heard, the Earth and moon are found to be chemically similar. This is why the Giant Impact theory was later modified...right. To recap the origin of the moon:
1) giant impact into early earth.
a) impactor (s) is similar chemically to earth, or
b) impactor is made of ice...ice then melts leaving no trace
2) Portion if Earth gets thrown into orbit and forms a ring
3) ring coalesces into moon...voila!
sound right?

Sorta keeping in mind that there is only one theorized major impact like that and that the Earth was still in a reasonably molten state.

This is a very different situation to what were trying to model in your opening statement

After an impact, can a projection from the surface of a spinning planet obtain an orbit?

I would expect it not to enter an orbit.
The main reason is because the projectile would have next to zero horizontal velocity. That is why you see your simulations
show a falling back to earth

I assumed the spin of the Earth would create the orbits seen in "Newton cannon", but it does not. It always falls back to earth.

why assume that ? The cannon balls DONT achieve orbit, they fall back to Earth under gravity and air resistance
Also the cannon balls are not being launched vertically as would ejecta from an impact
Any horizontal velocity obtained by the rotation of the Earth is negated by the same rotation of the Earth below it.
The projectile would have to have additional horizontal force applied, thrust, to get it start orbiting and stay in that orbit till
decay occurs after the additional thrust was removed.

Ejecta from asteroid impacts goes up and either falls back down or it will be launched into space probably never to return
( assuming it has attained escape velocity). This is very rare considering the high escape velocity of the Earth


regards
Dave
 
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  • #5
A.T.
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  • #6
davenn
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The "Newton cannon" is a thought experiment, where a cannon ball fired horizontally fast enough would achieve orbit (if there was no atmosphere to slow it down).

https://en.wikipedia.org/wiki/Newton's_cannonball


Exactly ! :smile: :smile: that I know
and it isn't applicable in the scenario of the OP
 
  • #7
A.T.
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After an impact, can a projection from the surface of a spinning planet obtain an orbit?
With a single massive spherical body, any trajectory is a closed ellipse, so it returns to the starting point. But with a second massive body (like the Moon) it's different, and if it gets close enough to the other massive body, it can be caught by its gravity.
 
  • #8
MarkL
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Is there a venue to try out new ideas? Maybe form a group in Gab...similar to twitter.
I saw "against the mainstream" on Cosmoquest, but didn't appeal to me.
Maybe this forum has something I am unaware of...Thanks
 
  • #9
jbriggs444
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Is there a venue to try out new ideas? Maybe form a group in Gab...similar to twitter.
I saw "against the mainstream" on Cosmoquest, but didn't appeal to me.
Maybe this forum has something I am unaware of...Thanks
Not around here. Unless you have a peer-reviewed article as a basis for discussion, argument against science as it is taught and generally understood will get your thread closed down.
https://www.physicsforums.com/threads/physics-forums-global-guidelines.414380/ said:
We wish to discuss mainstream science. That means only topics that can be found in textbooks or that have been published in reputable journals.
 
  • #10
berkeman
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Is there a venue to try out new ideas? Maybe form a group in Gab...similar to twitter.
I saw "against the mainstream" on Cosmoquest, but didn't appeal to me.
Maybe this forum has something I am unaware of...Thanks
Many years ago we did have a dedicated sub-forum for new idea proposals. There was some basic vetting of the thread starts and some attempt to moderate the discussions after they were approved, but that forum proved to be totally impractical and it was shut down. (I don't even remember the name of that old sub-forum)
 
  • #11
anorlunda
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Try Reddit
 

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