Posted on 07/30/2004 11:12:50 AM PDT by PatrickHenry
We could be alone in the Universe after all. The discovery during the past decade of over a hundred planets around other stars has encouraged many scientists to think that habitable planets like ours might be common. But a recent study tells them to think again.
Martin Beer of the University of Leicester, UK, and co-workers argue that our Solar System may be highly unusual, compared with the planetary systems of other stars. In a preprint published on Arxiv1 [footnote's link in original article], they point out that the alien planets we have seen so far could have been formed by a completely different process from the one that formed ours. If that is so, says Beer, "there won't necessarily be lots of other Earths up there".
Most of the planets around other stars, known as extrasolar planets, are detected from the wobble that they induce in their own sun's motion. This wobble is caused by the gravitational tug of the planet on the star. Because stars are much bigger than planets, the effect is tiny, and it is only in the past decade that telescopes have been sensitive enough to detect it.
Even then, the wobble is detectable only for giant planets, which are those about as big as Jupiter, the bloated ball of gas in our Solar System. It is not possible at present to detect planets as small as the Earth.
Jupiter is not habitable: it is too cold, and is mostly composed of dense gas. And it is unlikely that extrasolar giant planets would support life either. But astronomers generally assume that if they detect such a planet in a distant solar system, it is likely to be accompanied by other, smaller planets. And maybe some of the smaller planets in these systems are just like Earth.
This is what Beer and colleagues now dispute. They say that the properties of almost all the known extrasolar planets are quite different from those of Jupiter.
Hot Jupiters
There are 110 of these extrasolar planets, at the latest count, and they are all between about a tenth and ten times as massive as Jupiter. Most of them are, however, much closer to their sun than Jupiter is to ours: they are known as 'hot Jupiters'. They also tend to have more elongated orbits than those of Jupiter and the Earth, both of which orbit the Sun on almost circular paths.
Ever since Copernicus displaced the Earth from the centre of the Universe, astronomers have tended to assume that there is nothing special about our place in the cosmos. But apparently our planetary system might not be so normal after all. Is it just chance that makes Jupiter different from other extrasolar planets? Beer and his colleagues suspect not.
They suggest that other planets were not formed by the same kind of process that produced our Solar System, so they might not have smaller, habitable companions.
Different recipes
The planets in our Solar System were put together from small pieces. The cloud of gas and dust that surrounded our newly formed Sun agglomerated into little pebbles, which then collided and stuck together to form rocky boulders and eventually mini-planets, called planetesimals. The coalescence of planetesimals created rocky planets such as Earth and Mars, and the solid cores of giant planets such as Jupiter, which then attracted thick atmospheres of gas.
But that is not the only way to make a solar system. Giant planets can condense directly out of the gaseous material around stars, collapsing under their own gravity. This process, which generates giant planets with a wide range of orbital radii and eccentricities, does not seem capable of producing the rocky planets seen in our own Solar System, which is why it has generally been ignored.
Yet it might account very nicely for the known extrasolar planets. "It wouldn't surprise me if there are two different ways that planetary systems are formed," Beer says. But how can we know if that is the case? "Probably the best way is just to gather more observations," says Beer. Only then can we know how unusual we really are.
"There are BILLIONS AND BILLIONS of galaxies"
Didn't you steal that line from Sagan?
"Billyons and Billyons!
Yes, but she never gets into trouble though. Because her big, burly brother is Pütdownda Beer
Why. Complexity theory indicates the opposite. Randomly formed objects are far and away the most complex.
I think a better question is why wouldn't complexity lean more toward design? You'd never walk up to a pyramid and say it was the result of time and chance, but you look at soemething as complex as the universe and say that it happened randomly? I don't get that. Please explain.
Pyramids are less complex than The Universe. Thus they are less likely to be generated by chance. (Roughly speaking.)
That makes no sense whatsoever and I think you know that. Tornado in a Junkyard
"Pyramids are less complex than The Universe. Thus they are less likely to be generated by chance. (Roughly speaking.)"
You're working backward from the answer.
They fall out side the life zone and/or are not the correct size to sustain an atmosphere. We are just beginning to explore our own neighborhood.
This is the point of Rare Earth. The idea behind the Drake equation properly applied, means that the habitable zones of galaxies, combined with the number of stable stars, with gas giant in circular orbits, combined with the number of solar systems with rocky planets with the right atmosphere and the correct distance from their star, plus dozens of other factors necessary for advanced life forms, whittles away at the billions and billions of stars, until it becomes improbable that there are other inhabitable planets let alone ones with advanced life.
For the record, I do not believe there are life bearing planets out there; however, I do suspect there are.
I'm not sure I understand what you were trying to say with that statement.
The question was whether the Bible said anything about other planets within the universe. I quoted Genesis 1. That's all.
The universe isn't as neat and tidy as the anthropists would have us believe. Sure there are laws you can't break or bend, but they still allow for a lot, and serendipity is very much a part of the cosmos.
Wow! That is a heck of an unsubstantiated assumption. The more complex something is, the more random it is? So a Chevy Nova is mroe random than bicycle?
Even then, the wobble is detectable only for giant planets, which are those about as big as Jupiter, the bloated ball of gas in our Solar System. It is not possible at present to detect planets as small as the Earth.
Doesn't this last sentence invalidate the premise of the article?
A Chevy Nova may seem complex to mechanically disinclined, but compared to what goes on inside the human body, underneath the Earth's mantle, or the interior of a star, it's about as complex as Alec Baldwin.
I wasn't arguing for the complexity of the Chevy Nova, I was argue that under your definition a Chevy Nova is more random than a Bicycle. That makes no sense.
There goes that Nature rag again, trying to ruin the "facts" that have already been decided on by the Science Gods.
The important thing is that by signing the 1967 UN Outer Space Treaty, the US and all other signatories have asserted sovereignty over the entire universe, but also have agreed to not develop anything in outer space unless one or more withdraw from the treaty. Withdrawal will take one year.
More specifically, he asserted that you "didn't know beans" about it, which was pretty funny coming from a guy who thought that a circle wasn't an ellipse, that infrared light caused sunburn, and that 1720 was a really, really big number.
*sigh* I'm trying very hard to make a simple point. Genesis 1 says "And God set them in the firmament of the heaven to give light upon the earth" in other words, that the sun, moon and stars are there to provide the earth with light.
Do you agree with this statement or not???
(Yes, it's a trick question - Do you have enough faith in what you claim to believe to support a single sentence in your Faith's Holiest Work?)
"Now I know what you're thinking, did he ask six questions or five?
Being that this is the most powerful question in the universe, and can blow your soul clear to Hell, you gotta ask yourself the question:
Do I feel faithful?
Well, do ya? Punk?"
Just answer cuz "I gots ta know"...
Having owned one, I'd have to say yes...
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