X-rays reveal the violent side of the universe

In astronomy, X-rays look at interstellar gas heated to millions of degrees around extreme environments like black holes, neutron stars, and colliding galaxies.

VLBI reveals the universe in amazing detail

Very Long Baseline Interferometry, or VLBI, links together widely separated radio telescopes to allow astronomers to see the universe in more detail than ever.

Sidereal time: What is it?

Sidereal time measures the rotation of our planet relative to the stars. It allows astronomers to keep time without worrying about the motion of Earth around the sun. 

Venus transit on June 5-6: Everything you need to know:

The Venus transit appeared as a small dark dot crossing sun's face for last time this century on June 5-6, 2012. Last transit of Venus in our lifetimes!

Three planets – Mars, Saturn, Venus – at nightfall throughout May 2012

Three planets light up the sky as soon as darkness falls on these May 2012 nights. This post tells you how to spot them.

Why was Venus so bright in late April and early May 2012?

Venus is at its brightest in late April and early May 2012. It's so bright it might surprise you. Some will report it as a UFO. But why so bright?

2012 annular eclipse of the sun – China to Texas – in May

Everything you need to know - whether you're in Earth's eastern or western hemisphere - about the 2012 annular eclipse of the sun.

Venus-Jupiter conjunction of March 2012

See the Venus-Jupiter conjunction in March 2012. They're spectacular this month - and near the moon by the month's end. Charts here.

Finding Comet Garradd in December 2011

Search for Comet Garradd before dawn and in the eastern sky, starting around the December solstice. Look for it with binoculars.

Moon facts at your fingertips

See below for a list of links to fun and useful facts about Earth's companion world. Learn these moon facts and impress your friends.