In my January column, I challenged readers to look for some of the finest naked-eye features on the Moon during lunar perigee — when the Moon is closest to Earth in its elliptical orbit. But have you ...

Intuitively, we all know that when we see an image of an object, it could either be large and far away or small and close by. Only with a three-dimensional measurement can we actually know what's ...

Using the unique capabilities of telescopes specialized on cosmic gamma rays, scientists have measured the smallest apparent size of a star on the night sky to date. The measurements reveal the ...