Astronomy Picture Of the Day (APOD)M24: A Sagittarius Starscape
Many vast star fields in the plane of our Milky Way Galaxy are rich in clouds of dust, and gas. First and foremost, visible in the above picture are millions of stars, many of which are similar to our Sun.
Seeing Through Saturns C Ring
Are Saturn's rings transparent? The Cassini spacecraft that recently entered orbit around Saturn has confirmed that some of Saturn's rings are more transparent than others. Pictured above, Saturn's main A, B, and C rings can be seen, top to bottom, superposed against the gas giant planet.
Earths North Magnetic Pole
A magnetic compass does not point toward the true North Pole of the Earth. Rather, it more closely points toward the North Magnetic Pole of the Earth. The North Magnetic Pole is currently located in northern Canada.
M55: Globular Star Cluster
The fifty-fifth entry in Charles Messier's catalog, M55 is a large and lovely globular cluster of around 100,000 stars. Only 20,000 light-years away in the constellation Sagittarius, M55 appears to earth-bound observers to be nearly 2/3 the size of the full moon.
IC 1805: Light from the Heart
Sprawling across hundreds of light-years, emission nebula IC 1805 is a mix of glowing interstellar gas and dark dust clouds. Only about 7,500 light-years away, stars were born in this region whose nickname - the Heart Nebula - derives from its suggestive shape (seen here sideways).
Microquasar in Motion
Microquasars, bizarre binary star systems, generating high-energy radiation and blasting out jets of particles at nearly the speed of light, live in our Milky Way galaxy. The energetic microquasar systems seem to consist...
Above the Eye of Hurricane Ivan
Ninety percent of the houses on Grenada were damaged. Such is the destructive force of Hurricane Ivan, already one of the most powerful and destructive hurricanes on record. And the storm will likely make landfall in southern USA tomorrow.
Genesis Missions Hard Impact
A flying saucer from outer space crash-landed in the Utah desert last week after being tracked by radar and chased by helicopters. No space aliens were involved, however. The saucer, pictured above...
Identify this Phenomenon
What caused this ring of colors? At the time of this writing, MIT Physics Professor Walter Lewin had yet to find someone who can give the correct explanation. Not students. Not colleagues. Not APOD editors. He wonders how the astute readers of APOD will do. Can you match wits with Professor Lewin?
Mercury: A Cratered Inferno
Mercury's surface looks similar to our Moon's. Each is heavily cratered and made of rock. Mercury's diameter is about 4800 km, while the Moon's is slightly less at about 3500 km (compared with about 12,700 km for the Earth). But Mercury is unique in many ways.