Dr. Katherine Volk

And having even one event would be a huge improvement on our knowledge of how many really small Kuiper Belt objects there are.

So that is our best chance of constraining the one kilometer size things.

Oh, two.

Ah, that is an excellent question.

So if there's a 10 Earth mass or even an Earth mass planet out there, how was there enough stuff to build it?

And the answer to that is I don't know.

It probably didn't get built out there.

It probably got put out there.

But it turns out for this planet nine in particular, people have been looking into, you know, we think that it's possible we had an extra ice giant in the inner solar system when our ice giants and gas giants were forming that we kind of booted out of the solar system.

So people have looked at could that have landed on an orbit in the outer solar system?

It's a very low probability event.

There are probably also free floating really large planets that got kicked out of other solar systems.

but capturing them is a low probability event.

So it's possible that it's been either captured from another solar system or booted out from our inner solar system.

Hard to say if those are really likely.

In terms of like a Mars or an Earth mass thing, that's a little bit easier maybe to form

Kind of in the proto-Kuiper belt, we think there were many tens of Earth masses of material in the primordial Kuiper belt, and it has since been eroded away.

So it's not unreasonable that you'd have a Mars mass object just as a really large Kuiper belt object that then got put out into the Kuiper belt.

But the ten Earth mass object is a little bit trickier.

You'd have to form it closer in.