Astronomy Picture Of the Day (APOD)Titania's Trenches
British astronomer Sir William Herschel discovered Titania and Oberon in January of 1787. He wasn't reading Shakespeare's A Midsummer Night's Dream though, he was making the first telescopic observations of moons of the planet Uranus (a planet which he himself discovered in 1781).
Star clusters, planets, and a red giant posed for this portrait of the night sky from rural Jasper County, Iowa, USA. Astrophotographer Stan Richard recorded the four minute time exposure looking east around midnight on September 3rd at Ashton-Wildwood Park.
Heating Coronal Loops
Extending above the photosphere or visible surface of the Sun, the faint, tenuous solar corona can't be easily seen from Earth, but it is measured to be hundreds of times hotter than the photosphere itself. What makes the solar corona so hot?
Pictured above on September 3rd, the enclosure for the 8.2 meter telescope christened Yepun glints dramatically in the light of the setting sun. Later that evening, under dark skies at Paranal Observatory, Chile, astronomers...
In 1979 the Voyager 1 spacecraft compiled this view as it approached the gas giant Jupiter. Snapping a picture every time the Great Red Spot was properly aligned, the above time-lapse sequence shows not only spot rotation but also the swirling of neighboring clouds.
AR 9169: A Large Sunspot
One of the largest sunspots in recent years is now crossing our Sun. Dominating active region AR 9169, the sunspot is the large dark complex visible below (west) and right of center in the above photograph of our Sun taken last Thursday.
M16: Stars from Eagle's Eggs
Newborn stars are forming in the Eagle Nebula. This image, taken with the Hubble Space Telescope in 1995, shows evaporating gaseous globules (EGGs) emerging from pillars of molecular hydrogen gas and dust. The giant pillars are light years in length and are so dense that
The Equal Night
Yesterday the Sun crossed the celestial equator heading south, marking the Equinox -- the first day of Autumn in the northern hemisphere and Spring in the south. Equinox means equal night and with the Sun on the celestial equator, Earthlings will experience 12 hours of daylight and 12 hours of darkness.
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.
XZ Tauri System Ejects Gas Bubble
Why is the binary star system XZ Tauri emitting a hot bubble of expanding gas? Although astronomers can only presently speculate, the Hubble Space Telescope clearly documents this unusual behavior in three dramatic photographs over the past five years.