[ExI] Silence in the sky-but why?

[BillK]

On Mon, Sep 2, 2013 at 6:35 PM, Alfio Puglisi wrote:
<snip>
> 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.
<https://en.wikipedia.org/wiki/Extrasolar_planet>
Quote:
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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BillK