Stars

A mere 11 million light-years away, Centaurus A is a giant elliptical galaxy - the closest active galaxy to Earth. This remarkable composite view of the galaxy combines image data from the x-ray ( Chandra), optical(ESO), and radio(VLA) regimes. Centaurus A's central region is a jumble of gas, dust, and stars in optical light, but both radio and x-ray telescopes trace a remarkable jet of high-energy particles streaming from the galaxy's core. The cosmic particle accelerator's power source is a black hole with about 10 million times the mass of the Sun coincident with the x-ray bright spot at the galaxy's center. Blasting out from the active galactic nucleus toward the upper left, the energetic jet extends about 13,000 light-years. A shorter jet extends from the nucleus in the opposite direction. Other x-ray bright spots in the field are binary star systems with neutron stars or stellar mass black holes. Active galaxy Centaurus A is likely the result of a merger with a spiral galaxy some 100 million years ago.

The tantalizing Pleiades star cluster seems to lie just beyond the trees above a dark castle tower in this dramatic view of The World at Night. Recorded earlier this month, the starry sky also features bright star Aldebaran below the Pleiades and a small, faint, fuzzy cloud otherwise known as Comet Holmes near picture center at the top of the field. Starry Night Castle might be an appropriate name for the medieval castle ruin in the foreground. But its traditional name is Mörby Castle, found north of Stockholm, near lake Skedviken in Norrtälje, Sweden.


Astronomy Picture of the Day