Saturn is best known for its rings. This huge and beautiful ring system is easy to spot in even the smallest backyard telescope, so you can imagine they were a surprise when Galileo first noticed them. But astronomers have gone on to find rings around the other gas giant worlds in the Solar System –...

In 2006, the International Astronomical Union demoted Pluto out of the planet club. But they also started up a whole new dwarf planet club, with Pluto, Eris and the asteroid Ceres as charter members. Let’s find out what it takes to be a dwarf planet, and discuss the current membership. ...

Astronomers have been cataloging star positions for thousands of years, from the first calculations made by Hipparchus, to the more recent star catalogs made by the spacecraft named after him. This is astrometry; another way to find our place in the Universe. ...

Why are some objects in the Solar System bright while others are dim? Much of an object’s brightness is caused by its albedo, or how well it reflects radiation from the Sun. If you want to know how big a distant moon, comet, or asteroid is, you’ve got to know its albedo. ...

Today we tackle more thrilling mysteries of the Universe. And by tackle, we mean, acknowledge their puzzling existence. Some mysteries will be solved shortly, others will likely trouble astronomers for centuries to come. Join us for part 2. ...

All finished with the Milky Way, it’s time to move on to the biggest mysteries of all. The mysteries of the Universe. Let’s wonder about dark matter and dark energy, and the very nature of reality itself. ...

We survived our first group of mysteries, so now we move onto our second set of stuff of amazing Milky Way mysteries. How many spiral arms does our galaxy have, and why does everything keep dying every 60 million years or so? ...

We’ve wrapped up our Solar System mysteries and now we move onto the Milky Way mysteries, and the some of the general mysteries of galaxies. From blue stragglers to Eta Carinae… what’s going on? ...

Apparently this is at least a 2 part series. This week we continue examining some of the baffling mysteries of the Solar System, where we fill your head with more questions than answers. Sometimes we’ve just got to share the enjoyment of not knowing the answer. ...

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. ...