Quaoar – you say it KWA-ore. The Minor Planet Center of the International Astronomical Union gave it the number 50000, but what is it and where did its unusual name come from? Here are some facts about 50000 Quaoar.

1. Quaoar is one of the tens of thousands of icy bodies in the Kuiper Belt.
The Kuiper Belt is an enormous area of icy bits left over from the early Solar System. It starts just outside the orbit of Neptune, our most distant planet. An AU (astronomical unit) is the distance from the Earth to the Sun, so at 30 AU Neptune is thirty times as far from the Sun as we are. The Kuiper Belt then continues outward from Neptune for another 20 AU.

2. Michael Brown and Chad Trujillo discovered Quaoar in 2002 and named it for the creation god of the Tongva people.
Brown and Trujillo have discovered many faraway objects. They were observing at Palomar Observatory in southern California when they discovered Quaoar. It's one of a type of object that is named for creation gods. The astronomers chose a name that honored the Tongva people whose ancestors had lived in the Los Angeles area long before Europeans arrived.

3. Quaoar has a moon.
When Michael Brown discovered Quaoar's moon, he asked the Tongva community for a name. They liked Weywot [way.wot] who was Quaoar's son. Tiny Weywot is around 75 km (47 miles) across. If you were in a car, it would take less than an hour to travel that far. It orbits Quaoar once every 12.4 days, so a month on Quaoar is less than half an Earth month.

4. The days are short, but the years are very long on Quaoar.
A day is shorter on Quaoar than on Earth, just under eighteen hours long. However its journey around the Sun lasts 285 Earth years.

5. Quaoar is small, but still has enough mass to be round.
Quaoar is about half the size of Pluto, and Pluto's moon Charon is about ten times as massive as Quaoar. However Quaoar is still massive enough to be round.

6. Quaoar is red and covered in a layer of ice.
Quaoar probably gets its color from chemicals called tholins which are made of carbon, hydrogen and nitrogen. They're common on the worlds of the outer Solar System, and are what makes Pluto a pinkish color.

7. Quaoar probably has volcanoes.
There is a kind of ice on Quaoar that forms when ordinary ice is refrozen. That tells us that part of the surface of Quaoar has been melted and frozen again. Scientists think this happened by cryovolcanism. A cryovolcano is a cold volcano like the ones on Saturn's moon Enceladus and Jupiter's moon Europa. It throws out water instead of melted rock.

8. Quaoar is a cubewano – you say it cue-bee-WAN-oh.
The proper name of cubewano objects is classical Kuiper Belt objects. But the very first one they discovered got the number 1992 QB₁. Say “Q B one” and you'll see where the nickname came from.

9. Neptune's gravity doesn't affect cubewanos.
Since Pluto crosses Neptune's orbit, Neptune's gravity affects it. Neptune orbits at 30 AU, but cubewanos are too far away for Neptune to bother them. Even when Quaoar is at its closest to the Sun, it's 42 AU away.

10. A cubewano can also be a dwarf planet.
The biggest cubewano that we know of is dwarf planet Makemake [prounounced: MA.kay.MA.kay]. Quaoar is probably also a dwarf planet, but the International Astronomical Union hasn't got around to classifying it yet.