Watch Your Back, Pluto

July 29, 2005 4:19 PM

Big object sighted... if you liked Sedna and Quaoar, you're bound to love 2003 EL61, which has been found lurking in photographs from a couple of years ago. There appears to be some speculation that this one could be larger than Pluto.
posted by gimonca (19 comments total)

Here's the National Geographic article- same size as pluto, but with a moon. How can it not be christened a planet?
posted by efbrazil at 5:08 PM on July 29, 2005

Dammit! Now my horoscope is all messed up!

BTW, Pluto has a moon, and there's still ongoing debate about whether it's a planet or not (due to its wonky orbit and floppy ears, I think).
posted by Dipsomaniac at 5:22 PM on July 29, 2005

Let's not forget 2003 UB313!
posted by kodas at 5:23 PM on July 29, 2005

Never mind- Pluto is 2300 KM across, the new "object" is 1500 KM across. Pluto is pretty much taken to be the smallest size allowed for a planet (Mercury is much larger). So they get to keep this one labeled just 2003 EL61, and we can purge it from our collective consciousness.

Interestingly, Pluto is about 40 astronomical units from the sun, and the new object comes as close as 35 astronomical units. So the plane of Pluto, Neptune, and 2003 EL61 must all cross each others plane at some point. In order hype this discovery, they need to figure out how this object can cause a collision.
posted by efbrazil at 5:24 PM on July 29, 2005

kodas has it right: while 2003 EL61 is smaller than pluto, 2003 UB313 is, apparently, larger and the BBC already calls it a 'tenth planet'. The announcements came a day after the announcement for 2003 EL61. A remarkable coincidence.

BTW the astronomers announcing the discovery of 2003UB313, say that they "have proposed a name to the IAU and will announce it when that name is accepted". The title of the announcement page however suggests that the proposed name is Lila. So the tenth planet might end up being called Lila (somewhat dissonantly since the other 9 have names from Greek mythology).
posted by talos at 5:37 PM on July 29, 2005

Yeah, it's 2003 UB313 that's the one that's probably bigger than Pluto, not EL61.

I just hope they call it Rupert, after some astronomer's parrot.
posted by flashboy at 5:37 PM on July 29, 2005

EL61 on Wikipedia predicts no collisions, as they say the new object is likely resonance with Neptune, making it a a plutino. So never mind on that too. Back to work I guess...
posted by efbrazil at 5:44 PM on July 29, 2005

As long as those Planet X nutjobs don't get their bone, woohoo!
posted by angry modem at 6:03 PM on July 29, 2005

I love the fact that there's "fierce debate" over the line between planet and not-planet. Whatever. As if nature regularly deals in clear lines like that.
posted by mediareport at 7:41 PM on July 29, 2005

Well, this object is brighter then pluto, so people initialy thought it was larger then pluto as well. In fact, it's only more reflective.

Aaaanyway, if it had been larger then pluto, then people would probably have decided to call it a planet.

And when you think about it, it's almost random that pluto was descovered before this thing. Could have been the other way around and pluto would have been just some far off object.
posted by delmoi at 7:56 PM on July 29, 2005

delmoi, they don't know how reflective it (2003 UB313) is. Once they know how reflective is it, they'll be able to work out how big it is. But even if its albedo is 100% - making it the smallest possible, given its brightness - it would still be the same size as Pluto. So it's larger.

Or so the internet tells me, and it's never lied to me before.
posted by flashboy at 8:21 PM on July 29, 2005

I think by definition, a planet should be larger than any of the moons in the solar system. Bigger than Luna, biggers than... I dunno, Io, etc.
posted by blue_beetle at 9:59 PM on July 29, 2005

a planet should be larger than any of the moons in the solar system.

Talk about arbitrary.
posted by mediareport at 11:42 PM on July 29, 2005

Just to confuse you a bit further, there's also 2005 FY9 to deal with now. Initial reports did have speculation about the size of 2003 EL61 as well.

So there are three fairly well-sized items getting press at more or less the same time.
posted by gimonca at 6:44 AM on July 30, 2005

More, and more, and more, and more.
posted by gimonca at 6:52 AM on July 30, 2005

NIBIRU!
posted by glider at 7:02 AM on July 30, 2005

Oh great, now I have to worry about EL61 aligning with Mars and venus while Jupiter rises. I love new discoveries like this; it just continues to demonstrate what bullshit astrology is.
posted by j.p. Hung at 9:05 AM on July 30, 2005

So... are we calling it Mickey, or Rupert?
posted by Mayor West at 8:00 PM on July 30, 2005

I think by definition, a planet should be larger than any of the moons in the solar system. Bigger than Luna, biggers than... I dunno, Io, etc.

Ganymede. Sorry, Mercury!
posted by dhartung at 12:12 AM on July 31, 2005