posted on Sep, 10 2006 @ 06:38 PM
Originally posted by rizla
That article is about scientists running simulations. It's pure speculation. At the end of the day, Hot Jupiter systems are nothing like our own, and
are therefore less likely to harbour small rocky planets like Earth. If anything, the study of extra-solar planets suggests systems like our own are
not the norm. Of course, we need better data before a conclusion can be reached.
Yes, it's speculation, but it's speculation based on educated guesswork and a lot of observations. It's a close as we're going to get without
actually visiting the places themselves. You are correct in summising that systems with Hot Jupiters are nothing like our own and in all probability
preclude the formation of terrestrial planets as a whole. However, they don't have enough examples of the systems to be able to say definitively
anything about our own solar system, or even those types of systems in general. What the study of extra solar planets has shown is that only 5% of all
Sun like stars has planets of the Hot Jupiter type. Most Sun like stars don't have a Hot Jupiter....... they know this from radial motion studies. To
find a system like ours takes quite some time, considering that Jupiter orbits the Sun in a roughly 12 year orbit. To accurately measure the radial
velocity changes in a star with a Jupiter like planet in orbit usually takes 1-3 complete orbits......so it could take anywhere from 12-36 years of
observations to discover a planetary configuration much like ours. That's using present technology. They haven't been observing most systems for
that long. Hot Jupiters are only noticeable because of their short orbital periods and large radial velocity variations, that's all.
Consider this....... 4% of all the stars in the Galaxy are G class stars like the Sun. That's 16 billion stars. Take out those that are giants and
the minority of those in multiple systems which are not dynamically stable for planets (most multiple systems are in very wide separations between the
stars) and you have about 12 billion left. 70% of those G class stars are older than the Sun, and the majority of those were born between 10-8.5
billion years ago. That's 8.4 billion stars of G class older than the Sun. Given what they know about the formation of planets, pretty much all of
them should have at least 1 Earth like planet. Let's say 80% of them developed, through evolution, an advanced, technologically capable species, and
then 95% of them survived the "idiot stage" (that we're in at present). That leaves around 6.4 billion civilisations, in this Galaxy alone, that
would make us look like silly little children. They would have anywhere from (if evolution on their world was similar in length as on ours) 5.6 to 4
billion years ahead of us for the majority of them and from our stage to 4 billion years ahead of us for the rest.
And this is just with G class stars, alone.
We haven't even considered the F class stars of suitable size (those between F5 and F9).....another 6 billion stars. Or the K class stars.....another
50 billion. Or even those of M class that could harbour Earth like planets, which they now believe is likely and could number upto 100 billion stars
(out of a total of ~ 320 billion M class stars).
So, chances are, we're surrounded by alien beings who are for the most part very much our seniors. It would more than likely only be those
civilisation closest to us in technology (say between 100-1000000 years) that would probably have an interest in visiting us on a regular basis. Those
old civilisations would for all intents and purposes be God-like in their technological and social/evolutionary state......they'd know about us, but
probably don't need to visit us to know how we're getting along.