Pluto Demoted!

And just when I was getting used to the old proposed definition, it's been modified and voted on (237 for, 157 against, 30 abstain) to

[A planet is] a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a ... nearly round shape, and has cleared the neighborhood around its orbit.

So we now have 8 planets, MVEMJSUN, a class of "dwarf planets" (which I think are anything round but not unique in orbit), and "small solar system bodies" (anything else).

And to paraphrase my friend Foxtrot, despite what CNN says, this will not CAN not affect the New Horizons mission. It's already been launched.

ETA: Ugh. And despite what else CNN says, Ceres was never a planet. it was temporarily incorrectly called one when we didn't have an official definition. This (BBC) may be a better article.

ETAA: I'm liking this definition less and less. According to CNN, "Pluto is automatically disqualified because its oblong orbit overlaps with Neptune's." Well then, why isn't Neptune disqualified b/c it didn't clear out Pluto, et al.? It could be that Pluto's orbit's different enough that we can let it slide for Neptune's definition and then it's actually Charon and the Plutinos (ooh, a good band name!) that disqualif Pluto. But then what about Jupiter and its Trojan asteroids?

Seven signs of bogus science

As usual pointed out to me by the inimitable resurrected Sclerotic Rings, it's a list of the seven signs of bogus science! They're not meant to be a fail-safe set of criteria on which to judge what's good science and what isn't, just a starting point.

Planetary changes

People keep coming up with more interesting thought experiments to test the proposed definition of planet. This one, the changing orbit of the Moon. The Earth-Moon barycenter (center of mass) is currently within the Earth, however, the Moon is drifting away slowly, and in a few billion years, the Moon will be far enough that the barycenter will be outside the Earth's surface. Should that happen before the red giant Sun engulfs us, we'll have to have a Moon-Planet birthday party. Though, when the exact moment that happens is may depend upon things like if it's over Mt Everest or an ocean trench, and do we count the oceans and air and such as part of the Earth?

And what if there's a binary planet system w/ really eccentric orbits, or a mutliple planet system, then we might have the barycenter sometimes within a planet, and sometimes not, so the others would sometimes be moons and sometimes planets. Oy!

Mass Limit for Fusion

Astronomers may have found the lower limit on mass for nuclear fusion, and thus the upper limit for brown dwarfs, BBC reports. Unfortunately, they present some new misconceptions in the process - brown dwarfs aren't "dead" stars, they're stars that were never born, or perhaps overweight gas giants. But they never did have hydrogen fusion in the core, so they never stopped.

What Richer, et al., actually did was turn the HST towards a globular cluster in our Milky Way and take a 5-day exposure. (In reality they took multiple shorter exposures that were combined into one long one - no one takes a single exposure that long in case something goes wrong and because the tracking isn't perfect even on the HST.) In the image, the faintest stars they could see corresponded to 8.3% of the Sun's mass. If fainter stars existed Hubble would've been able to pick them up, but the article isn't on astro-ph and Science magazine restricts (free) access to the abstract only. If anyone has a subscription and can find the mass-equivalent detection limit of Hubble in the full article, I'd love to know.

Light Pollution makes BBC News

Read the article. Then check out the International Dark Sky association webpage.

links

It's amusing what you find when you do a search on your username. A year later, I found Inner Girl's link to me. :-P Thanks!

Stardust@Home

Reminiscent of the Clickworkers project, Stardust@Home uses human eyes to find specks of dust and cometary debris embedded in a piece of aerogel brought back from the Stardust space mission. Funny thing is, years ago as an undergrad one of my classmates gave a talk on his summer research project at NASA working on developing the aerogel...

Thanks to ian-atkin.net for the link/reminder to put something about this up.

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Below are the contents of two previous comments to this post; the original posts themselves were deleted (and further commenting prohibited) on request of the first author due to their name being included.

Anonymous said...

Hi, my name is ********.

sorry if I am wrong, but is this NASA that is wanting volunteers to search through the pictures? If they spent so much money on all the equipment, I think they would have planned for the laboratory work as well, unless they are using volunteers to discover the least important (unless unkwonwn) part of the aerogel.

Instead of using your time searching through pictures, look up some NASA UFO videos on youtube.com or video.google.com . Wouldn't it be better instead to ask NASA why they don't do live broadcasts anymore, and disclose all information they know of regarding the kind of objects or "UFOS" they almost certainly know about.
Either that or there so many people out there trying to mislead others for almost no apparent reason.
2:39 AM, August 20, 2006

zandperl said...

Hi,

The reason they need volunteers has three parts to it: (1) it is a task that computers are not yet able to do, and (2) it will take so many man-hours that it would take years with their current staff, and (3) if UC Berkeley and NASA were to hire people to work on it, they'd go bankrupt before they found anything.

As for UFOs, I personally don't believe they exist, and I think that the people who do think they exist want to believe and so are deceiving themselves when they see something they think is evidence of a UFO.
11:14 AM, August 20, 2006