Our Place in Space: Quaoar

Hello, friends!  Welcome to Our Place in Space: A to Z!  For this year’s A to Z Challenge, I’ll be taking you on a partly imaginative and highly optimistic tour of humanity’s future in outer space.  If you don’t know what the A to Z Challenge is, click here to learn more.  In today’s post, Q is for…


Ceres is a dwarf planet located in the asteroid belt.  In early 2015, Ceres became the first dwarf planet ever visited by a space probe from Earth.  Later that same year, New Horizons conducted its now famous flyby of Pluto, making Pluto the second dwarf planet we’ve visited.  So that leads to an obvious question: which dwarf planet do we want to explore next?  Well, there’s a chance it might end up being Quaoar.

Quaoar (pronounced either as kwa-war or kwa-o-ar) was discovered in 2002 by astronomers at the Palomar Observatory in southern California.  It’s named after the Tongva god of creation, the Tongva being an indigenous people native to southern California.  At the moment, we know that Quaoar is a Kuiper Belt Object, just like Pluto.  We also know that it’s about half the size of Pluto, that there’s signs of water ice and methane ice on its surface, and that it has at least one moon, named Weywot (the son of Quaoar, according to Tongva mythology).

So what makes Quaoar so special?  Why would we visit Quaoar next, rather than Orcus, Sedna, Eris, or the many other strange and mysterious dwarf planets we now know are out there?  The answer is simple: location, location, location.

Just as the Moon orbits the Earth, and just as the Earth orbits the Sun, the Sun orbits the central mass of our galaxy.  That means the Sun—and our whole Solar System, in fact—is moving through space.  Right now, there are at least two mission proposals to explore the interstellar space that lies directly ahead of our Solar System.  Coincidentally, Quaoar happens to be located near the “front” of our Solar System.  So if we’re launching space probes to explore the space directly ahead of our Solar System, it just makes sense to visit Quaoar on the way.

One of those mission proposals is American.  The other is Chinese.  I have no idea if or when either of these missions will get to fly.  It would be nice if both happen.  It would create an opportunity for American and Chinese scientists to coordinate their efforts and compare notes on what they learn about Quaoar, and later about the interstellar medium that lies ahead of our Solar System.  Such cooperation often occurred, even at the height of the Cold War, whenever American and Soviet space probes happened to visit the same planet at about the same time.  Space exploration has a way of bringing countries together.

Want to Learn More?

Here’s the proposal for the U.S. mission that would visit Quaoar, and here’s an article from Space News about the mission China is considering.