It is a bit bigger and somewhat colder, but a planet circling a star 500 light-years away is otherwise the closest match of our home world discovered so far, astronomers announced on Thursday.
This comes from Scientists Find an ‘Earth Twin,’ or Perhaps a Cousin in the New York Times.
Here is something that bothers me in this story, and in some of the pronouncements of astronomer’s in general. The way this is reported, it sounds like they know for sure that what they saw is 1) a planet; 2) of a certain size; 3) orbiting a Sol-like star; 4) orbiting in the ‘habitable zone’ of that star. All of these pronouncements are stated matter-of-fact-like.
Yet what do they really know?