Astronomy Picture Of the Day (APOD)The Pleiades Star Cluster
It is the most famous star cluster on the sky. The Pleiades can be seen without binoculars from even the depths of a light-polluted city. Also known as the Seven Sisters and M45, the Pleiades is one of the brightest and most easily visible open clusters on the sky.
Sirius: The Brightest Star in the Night
Sirius is the brightest star in the night sky. Intrinsically, Sirius is over 20 times brighter than our Sun and over twice as massive. As Sirius is 8.7 light years distant, it is not the closest star system -- the Alpha Centauri system holds this distinction.
VLT: A New Largest Optical Telescope
What is the largest telescope in the world? In the optical, this title was long held by the Hale 200-inch, and is presently held by the Keck telescopes in Hawaii. But an even larger optical telescope is being built.
Kepler Discovers How Planets Move
Johannes Kepler used simple mathematics to describe how planets move. Kepler was an assistant to the most accurate astronomical observer of the time, Tycho Brahe. Kepler was able to use Brahe's data...
Galileo Demonstrates the Telescope
Galileo Galilei made a good discovery great. Upon hearing at age 40 that a Dutch optician had invented a glass that made distant objects appear larger, Galileo crafted his own telescope and turned it toward the sky.
M17: The Majestic Swan Nebula
What unusual eggs have been laid by this majestic swan? The star forming region above, known as Swan Nebula, is the home of hot red-glowing gas, dark lanes of dust, bright young stars and -- what are those?
NGC 5882: A Small Planetary Nebula
Will most stars one day look like this? Pictured above is the planetary nebula NGC 5882, captured by the Hubble Space Telescope. Although planetary nebulae can appear similar to planets like Uranus and Neptune, they are actually gas clouds surrounding stars typically hundreds of light years away.
Galileo Zooms in on Jupiter's Red Spot
What does the largest storm system ever recorded look like close-up? This storm system is Jupiter's Great Red Spot and it was captured recently in detail by the robot spacecraft Galileo now in orbit around Jupiter.
A Wolf-Rayet Star Bubble
What's a Wolf-Rayet star, and how did it create that spherical bubble and sweeping arc? A Wolf-Rayet star is a star that originated with a mass over 40 times that of our Sun.
Luna 9: First Soft Lander
The Luna 9 spacecraft above performed the first soft landing on another planetary body. Following a series of failures, the Soviet probe touched down in the Moon's Oceanus Procellarum region February 3, 1966.