Building Worlds with Luke Skywatcher

But let's go right now to, as always, our joyfully cosmic cool thing.

Joyfully cool cosmic thing of the day.

Sorry.

Joyfully cool.

Once again, on the camera, you have reversed the order of some of the

words.

Well, I am always glad that you are there to correct me.

Thank you very much.

It's always good to have people making sure that you're on the straight and narrow.

So this particular cosmic cool thing of the day, thank you again, Alan, has to do with visitors to our solar system.

Now, the visitors to our solar system we're talking about are indeed the scientific ones that have made so much news in recent times.

It is those objects that have come in from outside our solar system into our solar system.

Most recently, 3I Atlas, what we think is an asteroid or comet type thing that has come in from somewhere far away.

And also, say, Oumuamua.

which came through our solar system and is already so far gone now we can't really detect it anymore.

But these interlopers have made us wonder, are they common or are they uncommon? Now, I'm going to interrupt for a moment the explanation of what event actually happened, because Luke, this is right in your wheelhouse, right? Your science has focused over the years on finding debris, pieces of things, asteroids, comets, and so forth, from solar systems.

Give us a little sense about the context of that.

What is the deal with stuff? Is it common? Is it rare? Does it fly out all over the place? Does it get swallowed up by itself? What is the basic sort of scientific milieu of these weird objects?

Yeah.

So what we're talking about are protoplanetary disks.

So after a star forms, some of the material that might have fallen into the star is actually cast into orbit around the star.

And it's gas and dust mixed together.

And dust is amazing stuff.

When my family has Thanksgiving dinner, we celebrate Thanksgiving, and we talk about what we're thankful for.

I'm thankful for dust.