What can we learn from whacking comets, up close and personal? What do comets tell us about the early solar system? And what is the role of comets in history?

In astronomy, it helps to get above it all. Three cool orbiting telescopes are collecting visible, infrared and X-ray light. We ogle their greatest hits.

Before planets, there was dust. But gravity doesn’t affect dust. So how did the planets form before solar wind blew all the dust away? Experiment shows that dust in planetary nebulas was coated with sticky ice.

Cassini finds lightning strikes on Saturn, haze on moon Titan, dust between the rings, and new rotation rate.

New view of crystals that form into planets in protoplanetary disks. Which came first, the planet or the crystals?

Amateur astronomers watch variable stars, asteroids, comets — helping create a better picture of the universe.

Infrared survey of Milky Way shows massive star formation. How could a supernova cause stars to start?

Astronomers have just seen galaxies from the first billion years of the universe. They are also racing to understand dark energy, the force that’s spreading the universe apart.

Bush proposes mission to moon and Mars, but how great are the scientific payoffs of this expensive, risky adventure? Would it be smarter – and cheaper – to send robots?

Why don’t the rings of Saturn just disappear over millions of years. It’s the recycling, that’s why!