Posted on 04/29/2005 10:22:03 PM PDT by neverdem
I just did some googling. Yup, appears you're correct. About 80 Jupiter masses is what's required to ignite into a star. Huh. Cool, learned something. Which is: don't trust Arthur C. Clarke *evil grin*.
http://www.badastronomy.com/bad/misc/jupiter_galileo.html
Qwinn
The way I read it last year, this was never in doubt. Hmmmmm. I wonder.
Bad Astronomy is an A-OK site, I highly recommend. :)
A lot of astronomy involves triple/quadruple checking.
They wanted to watch the set move in the sky over a significant period to be absolutely sure that they were gravitationally bound.
IIRC, they had other indirect evidence, but this is the first image.
No, last year they had imaged this planet initially but they were unsure if it was a companion object.
It had to be watched over a period of time to compare movement to background stars.
Prior to this, yes, all planets were detected indirectly.
If you look real hard you can see the little green man waving the sign "Hi, Mom!"
Thanks for the link.
This is an interesting link: How to distinguish brown dwarfs from planets.
http://encyclopedia.lockergnome.com/s/b/Brown_dwarf#Distinguishing_light_brown_dwarfs_from_large_planets
Honestly, this info is causing me to have to redefine my terms. I pretty much always thought that a categorization as a star (which I believed included brown dwarfs) required ongoing fusion. But according to this, apparently not. Then again, they don't seem to be sure themselves how to classify it, since one minute they refer to it as "sub-stellar" and another minute they do call it a star. Frankly, without having ever undergone fusion, I would've called it a heavy planet. But I can see how the fact that it's uniform like a star (not much difference in chemical makeup based on depth) takes it out of the planet category too. Interesting. For about ten minutes. Think I'll go back to devoting my attention to the cool stuff like black holes/quasars/pulsars ;)
Qwinn
I haven't read Arthur C. Clarke, so I can't help you.
Its the lack of defining characteristics and a large statistical base to operate on.
Same issue we're having with planets and arguements on whether Pluto should be downgraded or Sedna upgraded (etc)
For immediate release
Among the most essential quests of modern astronomers, taking direct images of planets outside of our solar system is certainly up there among chart-toppers. Obtaining such images of a so-called exoplanet would enable scientists to study in detail the physical nature of the object and, in particular, to analyse the composition of its atmosphere. The astronomers' ultimate goal is of course to perform such analysis for earth-sized planets, in the hope of detecting a telltale signature of extraterrestrial life.
Such an ultimate objective is still at least decades in the future, as earth-size and even Jupiter-size planets around stars as old as the Sun are too faint to be detected by present-day technology.
Nevertheless, great progress can be achieved by taking images of giant planets orbiting much younger objects. Because giant planets a few tens of millions of years old are much hotter and brighter than their older brethren, they can be much more easily detected. Moreover, as the first tens of millions of years are considered to have been a critical period in the formation of Earth and of our own solar system, the study of nearby young planetary systems provides astronomers with invaluable insight on our own origins, something that is difficult if not impossible to decipher from investigation of old, mature planetary systems.
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See link for the rest of the press release.
Thanks for the link.
Red Speck Bump
Check comments# 5, 13, 14, 16 and 18 if you don't read the whole thread.
No, it was in 2010 that Jupiter gets ignited into a star, of that I'm absolutely sure. It was a good book, better than 2001 IMHO. In the very very lame sequel 2061, he expands on the consequences of Jupiter being a star and the availability of all the diamond that was ejected from the initial ignition (space elevators, etc.). In the utterly benighted and horrible 3001... well, frankly, it was just too awful to be described.
Qwinn
And posts #21, 23 and 29. I had the same objection you did, but that issue has been resolved.
Qwinn
Doh, post #39 was meant for fish hawk, not neverdem.
Qwinn
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