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Strangely glowing dark clouds float serenely in this remarkable and beautiful image taken with the Hubble Space Telescope. These dense, opaque dust clouds -- known as "globules" -- are silhouetted against the red glow of hydrogen gas and bright stars in the busy star-forming region, IC 2944. Astronomer A.D. Thackeray first spied the globules in IC 2944 in 1950. Globules like these have been known since Dutch-American astronomer Bart Bok first drew attention to such objects in 1947. Astronomers still know very little about their origin and nature, except that they are generally associated with areas of star formation. IC 2944 is filled with gas and dust that is illuminated and heated by a loose cluster of massive stars. These stars are much hotter and more massive than our Sun.

IC 2944 Emission Nebula

Globules in IC 2944

Photo credit: Copyright Anglo-Australian Observatory, Photographs by David Malin

Science Paper

Link to a 1997 Astronomy and Astrophysics paper on IC 2944 by Reipurth, Corporon, Olberg, and Tenorio-Tagle.

1. How big is the largest globule?

The largest of the globules in this image is actually two separate clouds that gently overlap along our line of sight. Each cloud is nearly 1.4 light-years along its longest dimension. Collectively, the clouds contain enough material to make more than 15 stars like our Sun.

2. What does Hubble's view reveal to astronomers?

Thanks to the remarkable resolution offered by the Hubble telescope, astronomers can, for the first time, study the intricate structure of these globules. The globules appear to be fragmented, as if in the process of being torn apart. When radio astronomers observed the faint hiss from molecules within the globules, they realized that the globules are actually in constant, churning motion, moving supersonically among each other. This chaotic motion may be caused by the powerful ultraviolet radiation from the luminous, massive stars. These stars also heat the glowing hydrogen gas, causing it to expand against the globules, leading to their eventual destruction. Despite their serene appearance, the globules may actually be likened to clumps of butter on a red-hot pan.

798KB MPEG Movie

Zoom-in to Thackeray's Globules

Animation Credit: Bryan Preston (Max-Q Digital/STScI)

Centaurus constellation region
Photo credit: Akira Fujii

IC 2944 Emission Nebula & Globules in IC 2944
Photo credit: Copyright Anglo-Australian Observatory, Photographs by David Malin

Constellation of Centaurus
Photo Credit: Akira Fujii