Features

Intruder Galaxies

Five billion years ago the Andromeda Galaxy flung two galaxies out of the Local Group and swallowed two others.

Where the Lunar Winds Blow Free

Air? On the Moon? Though there’s not much of it, the Moon’s atmosphere may help solve some nagging lunar mysteries.

Close Encounter with a Comet

In 1986 Giotto made headlines at Comet Halley. Last year it garnered less hype but more data as it flew past Comet Grigg-Skjellerup.

Departments

Behind the Scenes
Letters
Viewpoint
AstroNews
Space News
Amateur News
Reader Reports
Astronomy Books
AstroBytes
New Astronomy Products
Meetings and Events
Readings and Credits
Advertiser Index