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.

2001 January 15
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

Billows of Smog in the Outer Galaxy
Credit: Chris Brunt & Jerran Ontkean (DRAO, NRC Canada)

Explanation: Our Galaxy is filled with gas. Most of this gas is hydrogen, some is helium, but there is a trace amount of relatively heavy molecules, including carbon monoxide (CO) - a component of smog. The above wide-angle radio CO image shows the incredibly diverse structures that the molecular interstellar medium forms. Dense clouds show where stars may be forming and open voids may indicate the action of strong winds from massive, recently formed stars. This FCRAO Outer Galaxy Survey was recently re-processed at the Dominion Radio Astrophysical Observatory for inclusion in the Canadian Galactic Plane Survey, an international effort to map all constituents of the interstellar medium over large scales at high angular resolution.

Tomorrow's picture: Europa Rotating

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
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