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.

2023 April 3
A false-color yellow-on red radio image of our
Galactic Center shows yellow radio-emitting arcs above streaks and a
bright cocoon that contains our Galaxy's central
black hole.
Please see the explanation for more detailed information.

The Galactic Center Radio Arc
Image Credit: Ian Heywood (Oxford U.), SARAO;

Explanation: What causes this unusual curving structure near the center of our Galaxy? The long parallel rays slanting across the top of the featured radio image are known collectively as the Galactic Center Radio Arc and point 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 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 a constant magnetic field. Images from NASA's Chandra X-ray Observatory appear to show this plasma colliding with a nearby cloud of cold gas.

Tomorrow's picture: from inner mars


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