« Archives in May, 2016

A sky filled with life?

http://www.eso.org/public/news/eso1615/

Three new planets, similar in size to Earth, and orbiting close around a red-dwarf star have been found by the European Southern Observatory in Chile!

One of the trends coming out of the extrasolar planet searches of late is that there are actually a lot of planets orbiting in the green-bands of red-dwarf stars. It used to be thought that because the dwarf stars were cooler and had closer and smaller habitable bands, that there was very little chance of an Earthlike planet forming around these stars. It turns out that the red-dwarf stars seem to have much closer packed systems though, so it all evens out.

Red dwarf stars (class M) make up 80% of the stars out there, so this is very good news. https://en.wikipedia.org/wiki/Stellar_classification

I don’t have exact numbers, but for a WAG the other day, based on stellar densities, http://abyss.uoregon.edu/~js/ast122/lectures/lec26.html, of about 1 star per cubic parsec within the solar neighborhood, there should be close to a 100,000 stars within 100 LY of the solar system. (Volumes grow fast – note to sci-fi writers.)

Edit: Wikipedia gives 0.14 stars/pc^3 in the solar neighborhood, which would lead to 20,000 stars in a 100 LY radius sphere. This accords better with the closest stars (26 in a 12 LY sphere). https://en.wikipedia.org/wiki/Stellar_density. Nevertheless, space is big, and as we are discovering, it is far from empty!