NASA scientist Tom Barclay says new discoveries by the Kepler satellite mean habitable planets are no longer just "theoretical":
T. Barclay: These discoveries suggest that there are many habitable, small planets.
T. Barclay: Discussing habitable planets is no longer a theoretical exercise.
More top news
The number of children dying from cancer in the UK each year is falling, according to new figures from a major charity.
A mother who poked fun at a clothing company's portrayal of a woman getting out Christmas decorations has won thousands of supporters.
David Cameron will try to convince MPs that Britain should be striking so-called Islamic State targets in Syria on Thursday.