Dr. Katherine Volk

And that takes a lot of time in the Kuiper Belt.

And you have to do really precise measurements.

So this is showing...

one and a half years of motion for one of the objects in our survey so it starts here and goes through two of these retrograde loops we tend to do discovery imaging right in the middle of one of these retrograde loops because the motion is fastest then and you can also get a sense of the distance really quickly so if you just assume that it's not orbiting the sun at all

you can actually just assume all the motion is parallax.

And you'll get within 25% of the correct distance to the sun.

But it takes a lot more tracking to figure out what's its exact semi-major axis, eccentricity, et cetera.

So this contributes to the comparison here between asteroid belt and near-earth asteroid discoveries over time versus Kuiper belt objects over time.

So of course we had Pluto, and there was a very long time where there were arguments about, you know, is Pluto by itself out there?

You know, in the 70s there were discoveries of a few objects in the giant planet region that we call centaurs, and these are a transient population that come from the Kuiper belt into the giant planet region.

But it wasn't until 1992 that we got our first confirmed Kuiper belt object that wasn't Pluto.

And that basically was because that's when CCD imaging became good enough and computers really helped the search.

And then, of course, there was a lot of interest after that first one.

So the number of objects known kind of skyrocketed here for a little while, though the discovery rate has not been

you know, as large, it has these kind of two humps because there have been various survey efforts.

In the 2000s, there was a deep ecliptic survey that discovered a bunch of things.

And then out here are things like the Canada-France Ecliptic Plane Survey and the Pan-STARRS and other wider area surveys.

But, you know, it still has nothing on the asteroid belt.

And this is an out-of-date figure even just because I couldn't find a nicer one.

So, you know, there's something like 1,500 or 2,000 known Kuiper Belt objects, depending on whether you want to throw out the ones that we know so little about other than that they're there.