Images by Date
Images by Category
Solar System
Stars
White Dwarfs
Supernovas
Neutron Stars
Black Holes
Milky Way Galaxy
Normal Galaxies
Quasars
Galaxy Clusters
Cosmology/Deep Field
Miscellaneous
Images by Interest
Chandra for Kids
Multiwavelength
Sky Map
Constellations
3D Wall
Photo Blog
Top Rated Images
Image Handouts
Desktops
High Res Prints
Fits Files
Image Tutorials
Photo Album Tutorial
False Color
Cosmic Distance
Look-Back Time
Scale & Distance
Angular Measurement
Images & Processing
AVM/Metadata
Getting Hard Copies
Image Use Policy
Web Shortcuts
Chandra Blog
RSS Feed
Chandra Mobile
Chronicle
Email Newsletter
News & Noteworthy
Image Use Policy
Questions & Answers
Glossary of Terms
Download Guide
Get Adobe Reader
More Information
Groups & Clusters of Galaxies
X-ray Astronomy Field Guide
Groups & Clusters of Galaxies
Questions and Answers
Groups & Clusters of Galaxies
Chandra Images
Groups & Clusters of Galaxies
Related Podcasts
A Tour of Perseus
A Tour of Perseus (2014-06-25)
Download Image

More Information

More Images
Gravitational Lensing Explanation
(Illustration: NASA/CXC/M.Weiss)

Animation & Video

More Releases
1E 0657-56
1E 0657-56
(20 Feb 02)

Related Images
Bullet Cluster
Bullet Cluster
(30 Oct 08)
Abell 2029
Abell 2029
(11 Jun 03)
NGC 720
NGC 720
(22 Oct 02)
EMSS 1358
EMSS 1358+6245
(06 Sep 01)
1E 0657-56:
NASA Finds Direct Proof of Dark Matter



Credit: X-ray: NASA/CXC/CfA/M.Markevitch et al.; Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al.

This composite image shows the galaxy cluster 1E 0657-56, also known as the "bullet cluster." This cluster was formed after the collision of two large clusters of galaxies, the most energetic event known in the universe since the Big Bang.

Hot gas detected by Chandra in X-rays is seen as two pink clumps in the image and contains most of the "normal," or baryonic, matter in the two clusters. The bullet-shaped clump on the right is the hot gas from one cluster, which passed through the hot gas from the other larger cluster during the collision. An optical image from Magellan and the Hubble Space Telescope shows the galaxies in orange and white. The blue areas in this image show where astronomers find most of the mass in the clusters. The concentration of mass is determined using the effect of so-called gravitational lensing, where light from the distant objects is distorted by intervening matter. Most of the matter in the clusters (blue) is clearly separate from the normal matter (pink), giving direct evidence that nearly all of the matter in the clusters is dark.

The hot gas in each cluster was slowed by a drag force, similar to air resistance, during the collision. In contrast, the dark matter was not slowed by the impact because it does not interact directly with itself or the gas except through gravity. Therefore, during the collision the dark matter clumps from the two clusters moved ahead of the hot gas, producing the separation of the dark and normal matter seen in the image. If hot gas was the most massive component in the clusters, as proposed by alternative theories of gravity, such an effect would not be seen. Instead, this result shows that dark matter is required.

Fast Facts for 1E 0657-56:
Credit  X-ray: NASA/CXC/CfA/M.Markevitch et al.; Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al.
Scale  Image is 7.5 x 5.4 arcmin
Category  Groups & Clusters of Galaxies
Coordinates (J2000)  RA 06h 58m 37.9s | Dec -55 57' 00.00
Constellation  Carina
Observation Dates  2004: Aug 10, 11, 14, 15, 17, 19, 24, 25
Observation Time  140 hours
Obs. IDs  5355-58, 5361, 4984-86
Color Code  Energy (X-ray: Pink; Optical: White/Orange; Lensing Map: Blue)
Instrument  ACIS
Also Known As The Bullet Cluster
Distance Estimate  About 3.8 billion light years
Release Date  August 21, 2006