Welcome to Astronomy Cast, the most popular astronomy-related podcast. Just look at what listeners have to say about it: Astronomy Cast is out of this world! It's hard to believe that it's free! This is an absolute must for any amateur astronomer or anyone interested in astronomy or cosmology. The...

We know a lot about our Solar System, but there's an awful lot that's a complete and total mystery. Today we're going to begin a series of unknown length examining some of these mysteries, and explain the best theories astronomers have so far. ...

Even in ancient times, astronomers realized there was something different about the planets – they move! The movement of the planets and their moons are governed by gravity. And as we all know, gravity can do some funny things. ...

This is going to be one of those weeks where we tackle something you're mentally avoiding. You know all those astronomical terms, like alt-azimuth, right ascension and declination, arc seconds and arc minutes? Of course not, your mind has blocked them out. Today we're going explain them, so you...

Last week we talked about Fermi the man, now we're going to talk about Fermi the space telescope. That's right, Enrico Fermi made such an impact in the astronomy and physics community that he got a space telescope named after him. Let's take a look at what this mission will do, and its...

Deep field image by Hubble What if our universe was just one in an infinite number of parallel universes; a possible outcome from the specific predictions of quantum mechanics. The idea of multiple universes is common in science fiction, but is there any actual science to back this theory up? ...

Every now and then, the Moon destroys the Sun. Okay, not destroys, covers. Well, not really covers, but from here on Earth, sitting inside the shadow of the Moon, that's what it sure looks like. These events are called eclipses, or more precisely, transits and occultations. They occur whenever one...

Artist's illustration of the dwarf planet Eris. Image credit: NASA Astronomers have been searching for the mysterious Planet X for hundreds of years. It was the search for a theoretical planet beyond Uranus that turned up Neptune, and then again for Pluto. And even now there are some astronomers who...

Artist's illustration of a pulsar Imagine an object with the mass of the Sun, crushed down to the size of Manhattan. Now set that object spinning hundreds of times a second, blasting out powerful beams of radiation like a lighthouse. That's a pulsar, one of the most exotic objects in the Universe. ...

VY Canis Majoris This week we're going to talk about famous stars. But not those boring human ones you read about in People magazine. No, we're talking about those hot balls of plasma across the distant Universe. The close ones, the bright ones, the massive ones, the giant ones. Let's get to...