Okay, I’ve talked about Ceres and Pluto. That leaves the blind dwarves. I call them blind not because they can’t see (although they probably can’t), but because humans have not - yet - sent out a probe to get a good look at any of them. Our information on them is relatively skimpy, so this probably won’t take long.
Eris was originally (2003) thought to be larger than Pluto, and was submitted as our system’s 10th planet. Designated 2003UB313 (and nicknamed Xena), it is now named for the Greek goddess of discord and strife, which seems rather fitting, since it caused Pluto’s demotion.
Eris’ diameter is 1,445 miles [2,326 km], which makes it pretty close to the same size as Pluto. The motions of its moon, Dysnomia, shows that Eris is about 27% heavier than Pluto, which means it is denser - probably a large rocky body with a thin mantle of nitrogen-rich ice mixed with frozen methane. This surface may be a frozen atmosphere, which only becomes an atmosphere for a small portion of its 557 year trip around the sun. And unlike most of its siblings, Eris’ orbit sits far outside the plane the other planets inhabit.
One website stated that an Eris day lasts for 25 hours. Another stated that Dysnomia’s circular orbit around Eris takes 16 days.
First discovered in March 2005, its first ‘name’ was 2005 FY9, its codename was Easterbunny. I can pronounce Easterbunny, but what’s the proper pronunciation of Makemake? Is it Make-make? Mak-ee-mak-ee? Ma-kee-ma-kee? Well, never mind, let’s move on. Oh, wait, here it is. It’s pronounced mah-kee-mah-kee, which is the name of the god of fertility of the Rapanui, the native people of Easter Island.
Makemake’s diameter is 870 miles [1,400 km], which is about 2/3 the size of Pluto, and takes about 310 years to circle the sun. Its orbit is quite lop-sided, as it goes as far out as 53 Å* from the sun and gets as close as 38 Å, not quite far enough in to say hello to Neptune. Its day is 22.5 hours. It has no atmosphere, is reddish in color, and has been determined to have frozen methane, ethane and nitrogen on its surface.
Makemake has a moon. S/2015(136472)1 (nicknamed MK2) is approximately 100 miles [160 km] in diameter and lives about 13,000 miles [20,900 km] from Makemake. It’s the color of charcoal. It’s been suggested that MK2’s gravity is too weak to hold onto any ices that might have been on the surface, so they sublimated into space. Scientists are still watching MK2, trying to discern the shape of its orbit; if it’s circular, the moon was probably produced by an impact, but if it’s elliptical, MK2 was probably captured by Makemake’s gravity as they passed.
Even though Haumea was discovered in 2003, it wasn’t announced until 2005, about the time its 2 moons were discovered. It was designated 2003EL61 (and nicknamed Santa), then named after the Hawaiian goddess of childbirth and fertility. Its moons - Hi’aka and Namaka - are named for her daughters.
Despite being found before the other two dwarves, every website I visited had about 10 sentences on Haumea, most of it repeating what every other website said. So, here some sketchy details:
At its equator, Haumea’s diameter is about 1,200 miles (1,931 km), making it almost as wide as Pluto. But its mass is only 1/3 of Pluto, at least partially because the diameter from pole to pole is much less. Now, even dwarf planets are supposed to be spherical, so why is this called a dwarf planet? Well, they’ve cut it some slack because its ‘day’ is less than 4 hours. That speed has deformed it into something resembling a half-flat beach ball. There is speculation that an impact set it spinning so fast, as well as created its moons.
Haumea is believed to be a big rock with a coating of ices that takes 285 Earth years to make a trip around our sun.
Those are all the juicy tidbits I could find about the 3 ‘blind’ dwarves. However, as I was doing this research, I caught tantalizing hints of other discoveries that may be on their way to being named dwarf planets. If I can find enough information to make a blog, I’ll let you know about those, too.
There’s also been some speculation of a Planet 10 or Planet X, also located in the Kuiper Belt. I’ll look into that, too, but I’m not promising I’ll find much. I heard some hype about the possibility for a little while, and then it just seemed to fizzle out.
So, be sure to come back next week, kids! Same time, same channel. See you then!
*Å = Astronomical unit, the distance between the sun and Earth.