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 ...

How is astronomical distance determined? Just cannot get my head around cepheid variables, parallax, etc. How is it possible to tell how far away something is when you cannot bounce a radar beam off ...

How far away are the most distant objects in the Universe? How has the Universe expanded over the course of its history? And therefore, how big and how old is the Universe since the Big Bang? Through ...

Stars move slowly across the sky over very long periods. The closer a star is, the more easily we can see its movement. Stellar parallax is a shift in a star's apparent position due to Earth's orbit.

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 ...

THE determination of stellar parallaxes by photography has shown a striking improvement in recent years, and the results obtained with the Yerkes refractor are of the highest order of excellence. Two ...

The two images (above) that appeared in the news story “New star found near Sol” show the star’s proper motion, not its parallax. Proper motion is the apparent movement of a star across the sky year ...