No reason... just... this.

[hitchcockgreen]

[Dx.]

So that's supposed tobe an object doing the impossible to Earth, like a bullet being shot through the planet.
Not very realistic at all on the effects or object size.

[hitchcockgreen]

Nope, not at all.

[FirBirGir]

The moon wouldn't survive that either. That guy is screwed but at least he got to see the light show

[hitchcockgreen]

Hence his sentiment...

[Dx.]

Why wouldn't the moon survive it?
It would resettle into another orbitel path around the sun without the Earths gravity.
The Earth would end up a ring of rock in the orbitel path which would impact the moon alot eventually forming another planet. The moon would survive a very long time before that.

[Blunt Force Trauma]

Yes, "survival" is subjective in this case. Since the Moon is already a barren rock in vacuum and would just go through another epoch of high impact frequency, its survival is a shoulder shrug.

[FirBirGir]

The debris from the Earth would likely break up the moon. The energy released in a planetary collision would surely eject massive amounts of material into the moon's orbit. With a lot of luck, it could dodge it but it's unlikely.

[hitchcockgreen]

With the scatter of earth debris at a quarter of a million miles, I'd say the moon has a decent chance of not being smashed by larger chunks but still bombarded by smaller ones.

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[Dx.]

The moon survived high speed impacts over the last 4.5 billion years, i doubt low speed impacts from Earth debris could destroy it.

[hitchcockgreen]

Its not even so much the speed of the impact so much as the size of the impactor.

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[FirBirGir]

The mass of the moon is only 1.2% of the Earth's mass. If the Earth suffers a cataclysm that breaks it apart, there could easily be pieces as large as the moon itself floating in it's previous orbit (the orbit wouldn't really be an orbit anymore if the Earth is a debris field). Even at the low speed of 3,600 KPH, the moon colliding with something comparable in size would break it apart.

Of course none of us are astrophysicists or geologists, we're exercising our imaginations more than anything.

Eddy

[Blunt Force Trauma]

I'm not an astrophysicist, but I did do a minor in astronomy, sort of an astrophysicist wannabe. I think Firbir is on the right track. But I'm not sure a "breakup" of the Moon would occur. I would think much of the earth would re-coalesce, have a new ring system, and probably a good percentage of the resulting system's mass in Lagrangian points. It would then take several million years for the rings and L-points to decay from a process dominated by the Roche Limit.

In HCG's pic, it appears to be an object traveling at some low percentage of light speed. But in reality, objects, even solidified mass such as cold rock, at that scale impacting, would appear to behave almost like a fluid. It would make a plasma-like splash rather than a 'puncture'. It's been studied to death by the 'Giant Impact Theory' and it's daughter theories.

[Dx.]

Its not even so much the speed of the impact so much as the size of the impactor.

The amount of energy released is 4 times greater with speed rather than size and as said before, objects have hit the moon with far greater speed over the last 4.5 billion years and the moon is still there.

When objects of the same size hit, they are damaged but don't completely break apart, it takes alot more energy.

[hitchcockgreen]

I guess it would depend on just how fast a collision threw debris towards the moon.

[Dx.]

It won't be at 90k i'm sure.

[FirBirGir]

Its not even so much the speed of the impact so much as the size of the impactor.

The amount of energy released is 4 times greater with speed rather than size and as said before, objects have hit the moon with far greater speed over the last 4.5 billion years and the moon is still there.

When objects of the same size hit, they are damaged but don't completely break apart, it takes alot more energy.

There are examples in other star systems that contradict this statement. This article theorizes that two planets collided and created a massive dust field

http://www.sciencedaily.com/releases/20 ... 164646.htm

Slow speed impacts do act somewhat like a liquid but there is still massive amounts of mass ejected from the collision. The remaining mass will reform into a sphere eventually but it could be less than half the combined mass of the two original bodies. The higher the speed, the more mass would be lost. And we should keep in mind that it would be highly unlikely for another celestial body to collide with the Earth at relatively slow speed. Anything coming into our solar system is being pulled into our Sun gravitational well and by the time it got to Earth, it would be moving pretty fast. The Moon would suffer the slow speed impacts with the mass ejected from collision of the Earth and another planetary body and could possibly be with something greater than it's own mass and in essence swallow the moon whole.

Eddy

[Blunt Force Trauma]

Also remember, what would be a common cometary orbital velocity, 30,000 to 60,000 mph, would look like slow motion with two massive objects like the earth and the moon. Even a comet with an extremely elliptical orbit like Halley's is only around 160,000 mph at its fastest delta-V to earth. A moon sized object coming in would look a bit like the Pink Floyd video, hardly the wild impact we see in the original post.

As I said, HCG's pic looks to be some small percentage of light speed. But even the simulation studios get it wrong ALL the time. The Discovery Channel video shows the object coming in at several hundred thousand mph, yet in one scene over the city they have it merely traveling a couple thousand mph at best.

Of course HCG's object could be some freakish, out of system rouge fluke, with some crazy velocity, but that would be one in a trillion chance.

[hitchcockgreen]

Dude what are you talking about...it already happened! Didn't you see the picture? That proves it.

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[Blunt Force Trauma]

Wow. . .how perfectly serendipitous, I just ran across THIS.

Can't find much more than speculation. . and still. . .one in a trillion.