wrote:
Rodney Kelp wrote:


[Forwarded press release]

HOW SPECIAL IS THE SOLAR SYSTEM?

On the evidence to date, our solar system could be fundamentally

different

from

the majority of planetary systems around stars because it formed in

a

different

way. If that is the case, Earth-like planets will be very rare.


If I was an astronomer, I'd be very wary of making this kind of
statement. They've almost always proved wrong in past. Given that we
can't detect Earth size planets yet, nor are very good at finding
multi-year orbit big planets, this is just pure speculation. And this
type of speculation, that the Earth, Sun, or solar system is in some
way special, has a very bad track record. The principle of mediocrity
applies here (assume we are average unless there is some strong
evidence against it), and there is no evidence against it yet.
Lou Scheffer

Yes there is evidence against it. The evidence isn't very strong
but we are now getting some serious data on the matter. Well
the evidence is somewhat strong that our solar system is
fundamentally different from the majority of planetary systems
around stars. It is much weaker about Earth-like planets being
very rare. Most planets found to date are Jupiter sized or bigger
in an elliptical orbit with periapsis less than 1 AU. If Jupiter
had an elliptical orbit with periapsis less than 1 AU, then
Earths orbit wouldn't be stable and Earth wouldn't be.

Alain Fournier