Join our SkyWatch hosts for a weekly conversation that highlights news from the world of astronomy. Listen in via your computer or MP3 player as they bring the latest discoveries down to Earth. SkyWatch also includes HubbleWatch, a monthly round-up of news from NASA’s Hubble Space Telescope.
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About 54 million light-years from Earth, roughly 2,000 galaxies have ganged up in a gravitational grouping called the Virgo Cluster. Centering that cluster is a massive galaxy that is itself surrounded by many clusters-in this case, star clusters. But this massive galaxy has more of these star clusters than astronomers expected it to have. Could it be stealing from its neighbors?
In August, the Hubble Space Telescope completed its 100,000th orbit around Earth. Understandably, the venerable observatory is due for a little maintenance. In October, astronauts will be returning to Hubble to install two new science instruments, repair two other instruments, and upgrade other critical components on the telescope.
Hubble celebrated a new milestone in August – 100,000 orbits around the planet Earth. Scientists think they know why a certain galaxy has more globular clusters than its neighbors. And a black hole-inhabited galaxy is sending tendrils into the universe.
The Cassini spacecraft performed a daring flyby of Saturn’s moon Enceladus on March 12, flying about 15 kilometers per second (32,000 mph) through a geyser-like jet spurting from the moon’s surface. It captured sample molecules from the jet.
In August, it used special techniques to get pictures of the jets. Scientists want to know where the jets come from and whether Enceladus has water.
Could Earth’s Moon have water locked up inside its rocks? Samples brought back from the Apollo Moon mission may indicate that the answer is yes. Water may be locked up in volcanic glass beads within the rocks.
The Kuiper Belt is a region past Neptune, full of icy, comet-like objects. Pluto is the most famous Kuiper Belt object. Some of these objects have odd orbits that don’t fit with our knowledge of the solar system. A computer model suggests that the region may contain a really large body — 30 to 70 percent as massive as Earth — that affects the orbits of objects around it.
The Moon may be younger than originally thought – by about 30 million years. The Moon is thought to have formed after an object hit the Earth, partially melting the planet and propelling material into space. Because the Earth and Moon formed around the same time, this also brings up questions about our planet’s formation.
The Lincoln Near-Earth Asteroid Research (LINEAR) project scans the skies for asteroids in an attempt to find 90% of all the asteroids larger than 0.6 mile (1 km) in diameter by the end of 2008. In January 2008, LINEAR found an object now called Asteroid 2008 BT18. Original calculations suggested the asteroid was going to pass nearby the earth. Asteroid orbits can be altered by the Earth’s gravity, so the trajectory was uncertain. Luckily the object passed almost six times the distance between the Earth and Moon. But astronomers got a good look at the object, which turned out to be a lot more interesting than originally thought — it’s a binary asteroid.
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Carol Christian
& Jim O'Leary