The secret lives of black holes

A black hole’s spin may power gamma-ray bursts and galactic jets. But its rotation has been hard to measure – until now.

Web extra: An animated look at black-hole spin

See what astronomers are talking about with these animations of black holes.

Earth of the outer solar system

Each Cassini flyby of Titan fills in the details of this frostbitten saturnian moon shaped by forces identical to those that sculpted Earth’s surface.

Web extra: Titan: the new Earth?

Images from orbit highlight striking similarities between Earth and Titan.

The priest, the universe, and the Big Bang

A Belgian priest’s extraordinary insights anticipated modern cosmology’s most fundamental ideas.

Web extra: Lemaître, the calculator

The Belgian priest loved crunching numbers, and he embraced technology that helped him do it.

Illustrated: Making sense of galaxies

Astronomers’ efforts to explain galaxy types brought them from a tuning fork to a lemon.

How to observe variable stars

If your observing list doesn’t contain variable stars, here’s an easy guide to some of the finest.

Web extra: Presto change-o!

Watch these stars’ brightnesses change before your very eyes.

Who will save us from a killer asteroid?

Meet astronomers on the front lines of protecting Earth.

Web extra: Tunguska’s deep impact

Researchers may have discovered a previously unknown scar from the 1908 Tunguska meteor explosion: a deep crater lake.

Astrolight reflectors offer quality optics

Parks Optical’s 6- and 8-inch Newtonian reflectors deliver top-notch optics at a reasonable price.

Is LASIK for you?

Like any surgery, laser vision correction has pros and cons – especially for observers.

Web extra: Tough questions for your prospective eye surgeon

Don’t be reluctant to “interview” your doctor before you have LASIK or other vision-correction procedures.


This month in Astronomy
Bob Berman’s strange universe
Glenn Chaple’s observing basics

Web extra: Spy a solar system wanderer

Phil Harrington’s binocular universe

Web extra: The sky’s Triangle

Stephen James O’Meara’s secret sky
New products
Coming events
Advertiser index
Reader gallery