Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2002 May 21
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

The Galactic Center Radio Arc
Credit: Farhad Yusef-Zadeh et al. (Northwestern), VLA, NRAO

Explanation: What causes this unusual structure near the center of our Galaxy? The long parallel rays slanting across the top of the above radio image are known collectively as the Galactic Center Radio Arc and jut straight out from the Galactic plane. The Radio Arc is connected to the Galactic center by strange curving filaments known as the Arches. The bright radio structure at the bottom right likely surrounds a black hole at the Galactic center and is known as Sagittarius A*. One origin hypothesis holds that the Radio Arc and the Arches have their geometry because they contain hot plasma flowing along lines of constant magnetic field. Recent images from the Chandra X-ray Observatory appear to show this plasma colliding with a nearby cloud of cold gas.

Tomorrow's picture: Eiffel Planets

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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