[ExI] Silence in the sky-but why?

BillK pharos at gmail.com
Mon Sep 2 18:07:21 UTC 2013

On Mon, Sep 2, 2013 at 6:35 PM, Alfio Puglisi wrote:
> In the following years, all sorts of oddball systems have been found: some
> have multiple Jupiters close to the star, others have high-eccentricity
> orbits that periodically sweep a system clean of small debris like an
> Earth-sized planet, etc. It is true that selection effects still make it
> very difficult to detect whether a star hosts a planet similar to our own,
> but we know at least that our solar system, with all the planets in
> almost-round orbits and nicely grouped by size, cannot be taken as a typical
> example.

Initially extrasolar planets found were all giant planets because they
were easier to detect.
But the Kepler mission now has thousands of candidates.
In 2013, estimates of the number of Earth-sized planets in the Milky
Way ranged from at least 17 billion to at least 144 billion.


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