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First Other Solar System discovered
The first solar system other than our own has been discovered
only 44 light years away. Its planets are Jupiter-sized and its
discovery suggests that solar systems such as our own may be commonplace
in the Universe... potentially providing a fertile ground for extra-terrestial life.
The large size of the system's planets also invalidates all current planet-formation
theories.
Another poster was skeptical of these findings saying that so many of them can be attributed to things like "camera jitter" and such. Well, as I just said this is not the first planet that Marcy has found around other stars. He's been doing these experiments and getting good results for several years now. His experiments have been repeated and so far nobody has found any problems with them. I've come to accept that at the worst some of Marcy's extrasolar planet claims may wind up being disputed, but some of them are almost certainly planets. We're past the "camera jitter" phase in trying to come up with problems in the observations that Marcy is making.
Now, as for "invalidating all current theories of planetary formation" -- this isn't necessarily true. If Marcy is right this probably will bury all the theories which were in existence prior to his finding extrasolar planets. However, we've known of the existence of extrasolar jupiter-sized planets tightly orbiting other stars for a few years now and the shake-up in the theoretical community has already occured. There are now models out there which can account for this kind of star formation. One model that I know of suggests that many jupiter-sized gas giants are formed in the early solar system. As the solar system evolved there is a transfer of angular momentum between the orbits of these stars and the gas and dust and crap still remaining in the protoplanetary ring. The result of this angular momentum transfer is that the gas giant closest to the star will spiral into that star, then the next gas giant in line spirals into the star, and so on, until the gas and crap in the solar system is blown out of the system by the star and this process stops. When the process stops the solar system is left "frozen" in whatever configuration it was in. If a gas giant had nearly wound up plunging into the sun, then you'd see a gas giant in a very tight orbit. If, on the other hand you'd just lost a gas giant into the sun then the next one in line will have only started to spiral in and you'll see something similar to what our solar system looks like. It also makes the current results of this system of 3 gas giants, with one of them tightly orbiting, not too surprising and it might even be commonplace.
Unfortunately, I don't have a reference, but I saw a seminar on this theory and found it intriguing, and it would explain the existence of solar systems like this one and like ours. I don't think that this theory is necessarily correct, but just to point out that the damage to theories of planetary formation have already been done and that people are working on other theories which can explain what Marcy has been observing.
http://www.extrasolar.com/planetsearch.html seems to be a pretty good page of links. The first link on this page will take you to Marcy's extrasolar planet page at SFSU which is pretty much the authoritative source.
For those of you who (like me) can hardly find the Polar Star, here's a nice constellation-browsing site:
http://www.stargaze.force9.co.uk/.
-Lars
There are a number of other planetary systems
n cycl.html
that are likely, and one that has been known
but not exactly.
The known system is 55 Cancri, it has two large
planets.
The other "likelies" are Lalande 21185 and a bunch
of pulsars. Lal 21185 has at least two likely
companions that are detectable, but they are long
period orbits (est. 5.8 and 30 year orbits) so
they will take longer to confirm.
The only reason this is getting news is that both
the SFSU and AFOE teams concur on the system. I'm
not dissing on either team, they have both done
insanely cool work that is shattering and
rebuilding our understanding of planetary
sciences. The SFSU team, headed by Marcy and
Butler, have discovered or confirmed the majority
of the extrasolar planets that are known, and
continue to release new results every couple of
months.
For a great resource, check out the Extrasolar
Planets Encyclopedia at: http://www.obspm.fr:80/departement/darc/planets/e
gigantino.tv - Heavy but weighs nothing.
Are they balls of dirt?
What?
The inner one is almost certainly rock, as gas would have boiled away long ago (a planet orbiting that close to our sun would receive 350 times as much light per unit area as Earth).
OTOH, maybe a Jupiter-like planet's gravity well would be deep enough to keep it in.
I have questions about the equipment they are using and such, but the link dosn't answer much.
At least some of the planet-detecting experiments that produced results checked the doppler shift of stars' spectra, looking for periodic oscillations in how quickly it was moving towards/away from us. A regular oscillation means that it is being tugged back and forth by a planet orbiting it. This technique only works well for relatively large planets orbiting relatively close, which is why Jupiter-sized planets and larger are the kinds that are being detected.
I vaguely recall reading about another technique that actually looked for wobble in the star's position directly, but I could be mistaken about that.
While I do agree that this combination (three gas giants) is quite odd, it hardly "invalidates" modern formation theories.
Why? Because scientific theories are designed to predict the average cases - what should happen in a theoretical closed system with specific characteristics. The problem is that the universe is hardly this kind of system. Rather, it's a very real, huge system that is subject to every kind of improbability you can think of. This is what it means to say that "if it's not forbidden, it's compulsory". Thus, there is no reason to believe that there will be no exceptions when you apply such a theory to the real universe; the only way to know if it's a good theory is if these 'odd' ones are rare enough.
So far, we only have two planetary systems on which to test them, and while our solar system can very well be the 'odd' one, it's just as likely that the new one is the 'odd' one. Or that both are 'odd'. Or that none is.
To the editors: your English is as bad as your Perl. Please go back to grade school.
This is apparantly the fist time they've found _multiple_ planets around a single star, which apparantly qualifies as a solar system (that's not quite the definition of solar system that I've always used, but I'm not exactly the expert here). To me it sounds vaguely like a sports commentator saying: "...next up to bat is John Smith, who has hit more home runs on wet Tuesdays during his second at bat than any other player in the history of the game!"
I'm eagerly awaiting the day they can find something Earth-sized around one of these stars. Such things are sure to exist, whether we actually find them or not, it would just be nice to be able to point to them sometimes. I don't think that there's anything particularly unusual about the huge gas giants they've been seeing. After all, that's about the best they can manage to resolve, so that's what they're going to see if they're out there. The conditions that allow them to detect these planets may also make these planetary systems unusual. So, it's no great surprise that these discoveries throw the existing theories of planet formation on their heads, especially when you consider the fact that all we've had to form theories with is our own system.
Anyhow, AFAIK, they can't actually see the planets themselves. What happens, is that the star wobbles as the planets orbit it, kind of like with a binary star only to a lesser degree. Astronomers can see this with spectrascopes via the doppler effect (red and blue shifts in the spectrum). And with the calculated mass and revolution period of the orbiting objects they can figure out the distance, revolution period, number of bodies, etc.
Now, the planets observed (one way or another) all seem to be a) very massive; b) close to the star; and c) close to our sun. This is just because they are the easiest to be seen from our vantage. Bigger mass means more wobble. Close to star means more wobble. I don't see this as any difference to any theories. It is just easier to see the oddballs. But I am no expert so who am I to say?
Also, just because a planet has a greater mass than Jupiter doesn't mean it is a gas giant. Like I said they can't *see* the planets in any sense of the word AFAIK. It could be a really massive rocky planet. Besides, I wouldn't know how a planet can keep it's atmosphere so close to the sun. It would probably be blown away by solar winds (I am probably WAY off here). Look at Mercury which has an extremely thin atmosphere.
I am no expert so I don't claim anything I said as true it just a summary of what I read some time back. Please correct me.
Also, any place that keeps track of extrasolar planetary systems? That would make a nifty slashbox!
--
And 15 minutes ago you "knew" we
where alone in the universe.
"Men In Black"
Here's a link that has a cute orbital simulation, copies of the paper, and where to find Ups Andromidae in the sky. Much more info for the interested.
http://cfa-www.harvard.edu/afoe/upsAnd. html
Enjoy,
.. the term should be "planetary system." The name of our sun being Sol, the term "Solar system" describes our planetary system. This being the case, "extrasolar planetary system" would seem to be the best phrase to describe something like this.
We're going down, in a spiral to the ground
If humans were to ever set up a colony in another "planatary system" and used solar panels, whould we have to change the name to stellar panels instead? Or maybe Proximus Centari panels?
Well, it's an interesting question, and we could come up with several other examples. When we establish a colony on Mars and are describing an honest, straightforward colonist, would we describe him/her as being "down-to-Mars?" If we found a new, inhabitable planet with a sizable moon and set a spacecraft down on it, would we call it a "lunar" landing?
Over time, any language is going to pick up words (adjectives, specifically) that are tied to a specific place or object, inadvertantly or otherwise. The only point I'm trying to make is that "solar system" in this context is not strictly correct, and yes, I am picking a nit (as I admitted in the subject line.)
We're going down, in a spiral to the ground