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.
http://www.geocities.com/RainForest/Andes/9063/complexity.html
I couldn't get your link to work.
D'oh! Try this one instead:
http://www.geocities.com/RainForest/Andes/9063/kolmogrov.html
If we could ever get past our arrogance we might find that there is much yet to be learned.
Perfectly good form of the word.
That was a fine book. The authors are actual scientists with their heads screwed on tight. It happens that I totally agreed with their premise before they wrote the book, but when the book came out, although we are probably alone, I was no longer alone in that view. The book signaled a landmark change in direction of popular thought on the topic.
Rare Earth is exceptional as is Darwin's God.
As was pointed out, Rare Earth is not written by "religious" scientists. I do not recall God being mentioned at all. Darwin's God is written by a Christian who is not a creationist.
There were some posts about how we are finding that the Universe and Earth is much more complex than we originally thought. That is science's part. From that God becomes more complex than we originally thought (which is one of the conclusions of Darwin's God). That is religion's part. In both cases, it is man's arrogance that assumed both were simple, since that brings God and the universe down to our level.
It would be nice to know we are not alone in all this, but not really necessary if you believe in God. If you do not believe in God, it is imperative that we are not alone.
"No need to spend all that research money. All they had to do is read the Bible."
What??? Surely you jest, what other kind of work can "E's" do? This would be one massive retraining program.
Thanks for the ping!
After reading all the numbers bandied about, the millions and billions, it's probably a safe assumption (!) that these are numbers on the low side.
Now, as a firm believer in the Creator, and all the powers bestowed upon all that is in his Creation, I find it more than a bit absurd that, except for us, the entire Universe (not to mention the possibility of Multiverses) is little more than a toxic dumping ground for all the efforts of said creation.
And even if this were true, if we are the pinnacle of development of these creation efforts, why does the Universe continue (and continuously) create? To what point, for what purpose, is the Universe continuously expanding? If it turns out we're the best the Creator can come up with, why is this being done, especially on such a massive scale?
Doesn't life, as the most potent and most permanent aspect of creation, seek to express itself wherever it can do so, regardless of the environment in which it finds itself? Life being such a force as it is, wouldn't it find ways to adapt to and develop in said environment, and thus allow itself to revel further and more fully in grateful and joyous thanks to the Creator? In all the powers of Creation, is this the only test tube where such expression can manifest itself?
I have my own ideas on these things, but whether you are Creationist or Scientist, Believer or non-Believer, the numbers game alone does not auger well for the argument that We Are Alone.
Anxiously awaiting all flames!
CA....
True, But these big Jupiter+ size planets that orbit closer to their suns could have earth size/like moons. It might be rare that life forms on it's own separate planet. I am just guessing that orbiting a big Jupiter+ size planet would keep a body just as if not more stable than the moon does with the earth (Well assuming the earth like moons orbit far enough away to avoid becoming like Io).
I'm assuming you are off line for Sabbath. Please ping me when you are back.
Well????
Good Luck!..I'm glad your ready w/the extra fire retardant padding. :))
Well???
Good morning! Will you profess your faith today?
The subject of this thread is “Earthlike planets are more rare than thought” not Bash a Christian today. The question is whether or not there are other planets similar to ours capable of sustaining life elsewhere in the universe. The Bible seems to indicate there are not. For example Isaiah 45 verse 18 says the following:
For thus saith the LORD that created the heavens; God himself that formed the earth and made it; he hath established it, he created it not in vain, he formed it to be inhabited: I [am] the LORD; and [there is] none else.
I appreciate your concern as to my spiritual health and I want you to know have a deep concern for yours.
Not any that I know. The probability is high, but I have not seen the word "must" in a peer reviewed paper about life elsewhere.
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