If bursts occur within the Milky Way, the galaxy that contains the earth's solar system, they could be relatively small affairs quakes on the surfaces of neutron stars is one suggestion.

ECONOMIST: Astronomy

Our sun does not orbit another star, but roughly half of the stars in our Milky Way galaxy do, as part of a binary system.

MSN: 'Impossible' stars found in our galaxy - Technology & science - Space - Space.com | NBC News

But could there be intelligent life in another planetary system, in orbit around one of the 100 billion other stars in our Milky Way galaxy?

CNN: Three more homes for life in the universe?