ajmilne

Off topic for the wire, but my antennae picked it up, and it's pretty exciting, so I thought I'd drop it in here:

NASA's giving a briefing tomorrow (March 15), 1 ET.

http://www.ascribe.org/cgi-bin/spew4...=2004&public=1

Rumours I'm hearing: concerns an object about 3 billion km past Pluto, most distant heliocentric object yet discovered. I'm guessing if they can detect it that far out, it's a reasonable size.

Pluto averages around 5.9 billion km from the sun. So this thing is 1.5 times as far away.

ajmilne

More:

http://timesofindia.indiatimes.com/a...how/559814.cms

This source says 2 billion mi past Pluto (again, approx 3 billion km), provisionally called Sedna, more than 1200 mi in diameter, which puts it in the Pluto category (big for a minor planet, small for a major planet).

Tom Ames

Still in the Kuiper Belt, then, and not an Oort Cloud object.

thanks for the news update!

Mr. Bird

The Aussies have the same story , too.

From Hubble Space Telescope Daily Report #3568 found here (with a little help from the Bad Astronomy boards ):
(emphasis added)


One might guess from this that the HST will be having a look (if it hasn't already).

Jesse

So are the astrologers gonna have to change their charts now?

ajmilne

... probably, really, it's their option. Best comment on this so far, see Slashdot, 'astrology=syncretic religion' thread below:

http://slashdot.org/articles/04/03/1...id=134&tid=160

... and the writer probably has it right. Some will throw it in. Some won't. None or few among those who subscribe to their 'services' are going to be asking anyway. And whatever their answer, there's always a rationalization that can be managed. Such is the way of pseudoscience. When you're playing tennis without a net, you're at the mercy of the self-appointed umpire.

ajmilne

More at the BBC. NASA's press conference is really getting its thunder stolen. Link is:

http://news.bbc.co.uk/2/hi/science/nature/3511678.stm

... it may be larger than Pluto. And it was found with the Spitzer.

Rhaedas

http://www.cnn.com/2004/TECH/space/0...ery/index.html

CNN as well, they state though it's smaller than Pluto.

The whole "is it a planet or not" seems a bit ridiculous. At what point will we stop trying to draw this line, after a few more Kuiper objects are found? 10? Several hundred?

Anyway, by the original meaning, "wanderer", all objects directly orbiting the sun are planets. Anything orbiting them are moons. And anything orbiting a moon is...a moonlet?

It's nice to continue to confirm the availability of objects reaching outwards...more jumping off spots to the stars, if we can every establish ourselves as "space-faring".

Rhaedas

BTW, if this is being announced as a 10th planet candidate, then whatever happened to the one they were going to name Quaoar?

Side note: I bet the Planet X supporters will try and spin this, claiming that NASA is confirming its sighting to hush up rumors, but lying about its position.

ajmilne

Quaoar at 900 km diameter was probably too much in the league of other Kuiper belt bodies (Varuna, 2002 AW197) -- see http://www.gps.caltech.edu/~chad/quaoar/ -- for anyone to start saying 'Planet'. Note also that this is also around the size of the largest asteroid, Ceres, at about 950 km. Sedna, since it's more in Pluto's league, can more easily justify that 'tenth planet' headline. And 'Tenth planet discovered' has a lot more punch than 'largest object since Pluto discovered'.

But yeah, it's a pretty artificial debate. What's interesting about Sedna is to my mind more its distance *and* its size in combination. It's one more confirmation of a lot of educated guesses about the Kuiper belt. And it is a good size (as I said: small for a major planet, but big for a minor planet).

Conference at 1pm. Google News has a few more stories now, but not much more information out there yet. Few little tidbits you probably would have guessed -- not bad summary at:

http://www.sanluisobispo.com/mld/san...al/8190209.htm

-- Surface temperature below that of Pluto -- I saw -400 F, which would be about 25 K (Pluto is around 44 K) but Sedna's value is probably rounded off.

-- Ice and rock.

-- the sun from its surface would be about the size of a head of a pin (I assume held at arms' length; that's usually what an astronomer means by that)

-- actually discovered using Palomar's 48"; Spitzer used for confirmation

-- may have tiny red moon

-- highly elliptical orbit, period 10,500 years; loops out as far as 84 billion miles from the sun, or 900 AU