Astronomers quickly become used to dealing with huge numbers. For example, in any one lecture, I might declare that the sun emits some 400 billion trillion watts of power each second, that our Milky ...

Don't miss the big stories. Like us on Facebook. Astronomers quickly become used to dealing with huge numbers. For example, in any one lecture, I might declare that the sun emits some 400 billion ...

Let’s try a demonstration that we all enjoyed in elementary school. Close one eye, hold out your thumb at arm’s length, and align it with an object on the other side of the room. Without moving your ...

A reader from Jackson, Mo., asks, "How do astronomers know the distances to the various objects they talk about?" The answer is that astronomers use a "boot strap" process to determine distances over ...

On Jan. 15, 2025, the Gaia spacecraft took its last image. Then the craft ran a final round of engineering tests, fired its ...