Looking up at a clear, dark sky, you can see thousands of stars. Yet without binoculars or a telescope, the most common type of star is invisible. These are the small, cool red dwarfs that fill the sky and live practically forever.

Can sound travel in space? The short answer is no, but it's not so simple. The Sun produces sound waves we can't hear. And then there's a black hole that astronomers have detected endlessly singing a B-flat over tens of thousands of light years.

An enormous dragon circles the northern celestial pole. The constellation Draco contains a star that was the pole star at the time of the pharaohs, some interesting galaxies and the most complex planetary nebula yet discovered.

After all the fuss about Pluto, everybody knows that it's a dwarf planet now. But it's only one of five. Here's a mini tour of all five, including the one where a heatwave is the temperature of Antarctica, the one shaped like an egg, and one whose year is over 500 Earth years long. All aboard!

Join the dwarf planet tour. It will take you so far away that the Sun seems to be no more than another bright star. You'll see a dwarf planet the shape of an American football, one whose a month is the same length as its day, and the one that upset the fans of Pluto.

The objects in the night sky seem to be projected onto the celestial sphere. A coordinate system lets us say where everything is, but something's not quite right. The north polar star will be Vega one day. Astrological star signs don't match the constellations any more. What's going on?

Halley didn't discover a comet, but he did research and published papers in astronomy and many other fields. Russian Czar Peter the Great liked him as a dining and drinking companion and King William III put this civilian in charge of a Royal Navy ship. But how did he get a comet named for him?

While World War I was tearing Europe apart in 1915, a German physicist presented a theory that would shake up the way we see the Universe. The physicist was Albert Einstein, his face still unknown to the world, his name not yet a synonym for genius. How did a solar eclipse in 1919 change all that?

A fateful meeting of the Royal Astronomical Society in London adversely affected the lives of two scientists and hindered progress in the study of black holes for a half a century. So says the author of Empire of the Stars. Liked the book, but wasn't convinced.

For nearly ninety years Pluto was our ninth planet. Then in 2006, much to the annoyance of some, it was no longer a planet, but a dwarf planet. What happened? Eris happened. Some call Eris and Pluto twin planets, but they aren't twins. Eris has a secret.