2003 Ub 313: The Incredible Shrinking Planet?, No bigger than Pluto? Options

[Guest_BruceMoomaw_*]

(Thanks to Emily Lakdawalla):

http://sciencenow.sciencemag.org/cgi/content/full/2006/127/1

[elakdawalla]

(Thanks to Emily Lakdawalla):

http://sciencenow.sciencemag.org/cgi/content/full/2006/127/1

Actually SigurRosFan deserves the credit! I must get half of my blog entry material from the sharp-eyed people on this site...
http://www.unmannedspaceflight.com/index.p...indpost&p=39115

Since I posted that, I've gotten an email from someone saying that there will be a publication in Nature tomorrow that flip-flops again on the size of UB313 -- hopefully another sharp-eyed watcher will post that link here as soon as it appears!

--Emily

[Guest_AlexBlackwell_*]

Since I posted that, I've gotten an email from someone saying that there will be a publication in Nature tomorrow that flip-flops again on the size of UB313 -- hopefully another sharp-eyed watcher will post that link here as soon as it appears!

From the February 2, 2006, issue of Nature: One over the nine.

[JRehling]

Incidentally, don't forget that Pluto "shrank" throughout its lifetime, too, in at least two steps. I can remember when it was bigger than Mercury, and maybe bigger than Mars.

It would be interesting if size estimates consistently shrank for newly-discovered objects, as though there were a regression to the mean effect, or a pro-big bias on the part of the early researchers... Who wants to think that they discovered something tiny?

PS: Titan has shrunk a bit, too...

[TritonAntares]

Incidentally, don't forget that Pluto "shrank" throughout its lifetime, too, in at least two steps. I can remember when it was bigger than Mercury, and maybe bigger than Mars. 

It would be interesting if size estimates consistently shrank for newly-discovered objects, as though there were a regression to the mean effect, or a pro-big bias on the part of the early researchers... Who wants to think that they discovered something tiny?

PS: Titan has shrunk a bit, too...  

...as Triton did.

As child I read in an old astronomy library book from the '50s - I think it was from Otto Struve - Triton's diameter should be ~6000 km:
'Wow, a moon nearly as large as Mars...'
I'm not quite sure what it was before Voyager II - maybe about 3500 km,
but at the the end it came down to poorly 2720 km, probably the same size as UB313 now.

If we get more cases like Pluto, Triton, UB313, we'll find a 'shrinking law' from 'detection-diameter' to real diameter at the end...

Bye.

[Rob Pinnegar]

As child I read in an old astronomy library book from the '50s - I think it was from Otto Struve - Triton's diameter should be ~6000 km.

If I recall right, that was because of Triton's unexpectedly high reflectivity.

The 6000-km figure was still around in the 1970s; I'm pretty sure it was included as an upper limit in Ludek Pesek's book "Solar System" which was from about 1979.