This stunning picture was taken by the newly installed Advanced Camera for Surveys (ACS) aboard NASA's Hubble Space Telescope on April 1 and 2, 2002. It shows a region in the center of the Omega Nebula, M17, a vividly star-forming region and diffuse nebula of hot gas which shines from the excitation of its atoms (mostly hydrogen), caused by ultravioplet radiation of young hot and massive stars which it hosts - located just beyond the upper right corner of the image. These stars are each about six times hotter and 30 times more massive than the Sun. The powerful radiation from these stars evaporates and erodes the dense cloud of cold gas within which the stars formed. The blistered walls of the hollow cloud shine primarily in the blue, green, and red light emitted by excited atoms of hydrogen, nitrogen, oxygen, and sulfur. Particularly striking is the rose-like feature, seen to the right of center, which glows in the red light emitted by hydrogen and sulfur.

As the infant stars evaporate the surrounding cloud, they expose dense pockets of gas that may contain developing stars. Because these dense pockets are more resistant to the withering radiation than the surrounding cloud, they appear as sculptures in the walls of the cloud or as isolated islands in a sea of glowing gas. One isolated pocket is seen at the center of the brightest region of the nebula and is about 10 times larger than our solar system. Other dense pockets of gas have formed the remarkable feature jutting inward from the left edge of the image, which looks very similar to the famous Horsehead Nebula in Orion.

The region of the nebula shown in this photograph is about 3,500 times wider than our solar system. The area represents about 60 percent of the total view captured by ACS.

Credit: NASA and the ACS Science Team

This image was featured as Astronomy Picture of the Day (APOD) May 2, 2002

Full ACS frame of the M17 central region image.

Hi-res version of this image

Location of above Hubble Space Telescope image within M17, shown on an image taken at the Anglo-Australian Observatory by David Malin.

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More HST images of M17

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Hartmut Frommert
Christine Kronberg
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Last Modification: May 3, 2002