Could we find fragments of the Earth-Theia collision as we explore more asteroids?

[jfull]

The giant impact hypothesis has been one of the best explanations for the formation of the Moon, and it occurs to me that the theory could be proven if we found fragments of the collision.

However, I haven't seen anyone use this as justification for missions to near earth objects and other asteroids. Am I missing something, or would these fragments still be relatively common and easy to identify from their composition?

[Aethon]

You're standing on one.

[K^2]

And if you're not happy with this one, there are bits of the other one at the Smithsonian.

[SciMan]

... I do believe that jfull used the word "fragments" to indicate he meant the parts of the collision that didn't form the earth and moon.

I also thought that was the obvious meaning of their words, but evidence once again proves that I seem to be one of the few people capable of seeing the obvious for what it is.

On topic, I'm sure that those fragments exist, but I'm not sure how we'd tell that they weren't ejected from the earth or moon by a subsequent impact.

[ZetaX]

On topic, I'm sure that those fragments exist, but I'm not sure how we'd tell that they weren't ejected from the earth or moon by a subsequent impact.

If they are large enough, then there probably never was any other impact that could have created them. It might also be possible to find the age of an asteroid and check if it matches up. Possibly the orbit also tells something, but I am unsure wheather this really suffices.

[StrandedonEarth]

Most of them would have been eventually swept up by the Earth-moon system in the billions of years since.

[jfull]

Most of them would have been eventually swept up by the Earth-moon system in the billions of years since.

Meaning that some would have impacted the earth and moon, but a lot of others would just have been scattered.

[kiwi1960]

Given that what can be found on Earth can also be found entirely throughout our Solar system.... I'd have to say yes, but pin pointing it down to one object Theia is going to be your problem.

[Aethon]

... I do believe that jfull used the word "fragments" to indicate he meant the parts of the collision that didn't form the earth and moon.

I also thought that was the obvious meaning of their words, but evidence once again proves that I seem to be one of the few people capable of seeing the obvious for what it is.

Ok, so I was being slightly cheeky, but it's true. We have 5.97219 x 10^24 kg of fragment here, and 300 kg of fragments brought back from the moon. Any debris that didn't land on the Moon or Earth would look remarkably like a fragment of either the moon or Earth.

As far as I know there is no self consistent model of the giant impactor theory, that ends with only one moon.

[jfull]

But every object we find that matches the composition of the earth and moon would add credibility to the theory.

We may find that there's more out there than could be accounted for by more mundane impacts in earth's history.

We may also find that all those fragments solidified at about the same time.

[Aethon]

My point is, how do you tell a fragment of the alleged Theia impact from an ordinary chunk Earth or Luna knocked loose during the late heavy bombardment, or any other impact event.

Edited August 26, 2015 by Aethon

[jfull]

You don't necessarily determine that directly

But if you find 3 or more large fragments that all date to the exact same time, that would certainly suggest it.

[ZetaX]

My point is, how do you tell a fragment of the alleged Theia impact from an ordinary chunk Earth or Luna knocked loose in during the late heavy bombardment, or any other impact event.

If that chunk is a km in size, how else would it have originated¿ Either it was Theia or there was another really huge impact we don't know about.