Einstein’s century

Relativity turns 100

One hundred years ago, while working in the Swiss patent office, Albert Einstein invented a theory that touched off a revolution in physics. How did he do it?

The man who remade the universe

Einstein’s theories made him the world’s most famous scientist, but he also made his mark in politics.

Relativity’s infinite beauty

In the 20th century, general relativity became the preeminent theory for
decoding the cosmos. In the coming century, relativity will blaze new trails even as other theories try to supercede it.

Cassini/Huygens at Titan

When the Cassini spacecraft swooped past Titan in October, it got a super view of this enigmatic Saturn moon.

See a star die

Planetary nebulae — remnants of dead stars — are some of the most
beautiful celestial objects. Learn why these cosmic cadavers shine the way they do and which are the most dazzling to observe.

Explore a lunar debris field

Impacts transformed the region of lunar crater Janssen and the Vallis Rheita. The formation of huge, nearby basins pocked this area, making it look like a galactic battlefield.

Meet Mr. Eclipse

Globetrotting NASA astrophysicist Fred Espenak tells people when and where to go to view solar and lunar eclipses.

Backpack this scope

Costing less than $100, Celestron’s ExploraScope, the latest offering for young skygazers, is a bargain.


This month in Astronomy
Bob Berman’s strange universe
Glenn Chaple’s observing basics
A star by any other name
New products
Book reviews
Coming events
Advertiser index
Reader gallery