Dr. Katherine Volk

All right, thanks, Tim.

All right, so as Tim said, how's the volume by the way, is that okay?

All right, so I'm gonna be talking about unseen planets potentially in the Kuiper Belt.

So here's the roadmap for the talk that we're gonna quickly review, make sure everybody's familiar with the Kuiper Belt, talk a little bit about how we actually detect things out there because it's an important part of the story.

And then talk about how complete or incomplete our inventory is for the solar system, and really set the stage for why we've been talking so much lately about whether there are unseen planets out there yet to be discovered.

So first, quick tour.

So our solar system has two kind of what we call debris disks or belts of small bodies.

These are leftover things that didn't get made into larger planets.

In the inner solar system between Mars and Jupiter, we have the asteroid belt.

And then out past Neptune's orbit, we have the Kuiper Belt in the outer solar system.

So I'm just going to give a quick top-down view here of the Kuiper Belt.

So everything in white here is an observed Kuiper Belt object.

And we have Neptune, Uranus, Saturn, and Jupiter.

And then the sun and all the terrestrial planets would be tiny circles just mucking up the plot, so I didn't put them in.

And if we look on a kind of a side-on view, we see that there's some vertical structure here, which is going to play a role later on in the talk.

But we can see there's quite a few dots out here, but not nearly as many as we have for the asteroid belt.

And in the Kuiper belt, we have a couple different kinds of orbits.

Now we have what we call the so-called classical belts.

This is, again, a top-down view of the solar system, where the red circles here are things on low eccentricity, low inclination orbits that are kind of between 40 and 45 AU from the sun.

One AU, of course, is the Earth-sun distance.