Rhea was Saturn's wife in classical mythology. Rhea the moon zips around Saturn in four and a half days. Although it has an oxygen atmosphere, we won't be moving there anytime soon. Even in direct sunlight, it's -281 degrees Fahrenheit and the "atmosphere" is similar to a vacuum on Earth.

What does every astronomer need? Most people would answer "a telescope." But, actually, binoculars are the best way to start observing the sky. Many experienced astronomers use them in addition to a telescope. Here is some guidance about getting started.

Johann Elert Bode, the author of the greatest star atlas of the Golden Age of star atlases, is better known today for Bode's Law. Strangely, Bode's Law is neither a law nor original to Bode. So what was it? How did it inspire the Celestial Police? How did Neptune ruin it all?

Why do we have day and night? For thousands of years most people thought it was because the Sun went around the Earth. That is certainly what it looks like, so how can you explain that day and night happen because the earth spins on its axis? Here are some ideas.

Imagine the horror: Something is eating the Moon, leaving its face covered in blood. This was how people once viewed lunar eclipses. Find out what actually causes a lunar eclipse, why the Moon may turn red during an eclipse, and where a lunar eclipse becomes a solar eclipse.

The stars of Orion have been part of humanity's mythscape for thousands of years. Seven bright stars outline the hunter's body. One of them is a supergiant nearing the end of its life. Yet just visible to the unaided eye is a vast stellar nursery where the next generation of stars is forming.

Many bright stars sparkle in the sky on crisp winter evenings. Brightest of all is Sirius the Dog Star, the face of one of the two dogs of Orion the hunter. The belt of Orion himself is an easily-identified feature and the constellation also has both a red supergiant star and a blue one.

Two English policemen chased a UFO through the Devon countryside. It was the planet Venus. A news reporter had quite a scoop when she found a UFO hovering over New York City. It was the planet Jupiter. Why are planets and stars often mistaken for spacecraft or aircraft?

Saturn's rings, spiral galaxies, solar flares. Astrophotography has shown us some wonderful images, but it's more than pretty pictures. It has allowed us to discover objects too dim for the human eye to see. Partnered with spectroscopy, it moved astronomy from mapping to understanding the stars.

Halloween falls midway between an equinox and a solstice. In the ancient Celtic world it was the new year's eve and start of winter - time to prepare for survival in the darkening days. But also a time when the boundary between our world and the otherworld weakened. Who knew what might cross it?