Chandra X-ray Observatory - HomeAbout The ChandraEducational MaterialsField GuidePhoto AlbumPress RoomResources
Chandra X-ray Observatory - HomeChandra Field Guide - You are here
ObservatoryAbout X-ray AstronomyX-Ray SourcesSolar SystemNormal Stars & Star ClustersWhite Dwarfs & Planetary NebulasSupernovas & Supernova RemnantsNeutron Stars/X-ray BinariesBlack HolesNormal Galaxies & Starburst GalaxiesQuasars & Active GalaxiesGroups & Clusters of GalaxiesCosmology/Deep Fields/X-ray BackgroundMiscellaneousBrown Dwarfs Gamma Ray Bursts
Web Site ToolsVisit the Chandra ChroniclesEmail NewsletterSite MapNew & NoteworthyImage Use PolicyQuestions & AnswersGlossaryDownload Guide

Groups & Clusters of Galaxies

Chandra images provide dramatic evidence of these mega-mergers. Cosmic "weather systems" millions of light years across are observed, as relatively cool 50 million degree Celsius clouds of gas fall into much larger and hotter clouds.

Abell 2142
Chandra image of the galaxy cluster Abell 2142 in X-rays.
It takes a long time to build a galaxy cluster. Exactly how long depends on details such as the amount of dark matter in the universe, whether the dark matter is hot or cold, how fast the universe is expanding, etc. The pressure in the hot gas is an accurate probe of the amount of dark matter in clusters of galaxies. By using this information, and X-ray surveys to count the number of large clusters in the universe, astronomers can test the various theories for the content and evolution of the universe.

Chandra observations of the clouds of hot gas in clusters of galaxies will provide other clues to the origin, evolution and destiny of the universe. Combined X-ray and microwave observations can measure the effect of the cluster gas as it scatters the cosmic microwave background streaming through the cluster from the depths of the universe. The amount of scattering makes it possible to estimate the distance to the cluster. This information can be used to estimate the size and age of the universe.

Page 1 | 2 | 3


separator line
CXC Home | Search | Help | Site Map | Image Use Policy | Privacy & Accessibility | Downloads & Plugins
Latest Images | New & Noteworthy | Multimedia | Flash Ecards | Glossary | Q&A | Guestbook


RSS Feed RSS Feed | Podcast Podcast | Blog Blog

[News by email: Chandra Digest]
[Contact us: cxcpub@cfa.harvard.edu]
NASA's Home Page Smithsonian's Home Page CXC Home Page Image Map for NASA's, Smithsonian and Chandra's Home Pages
Harvard-Smithsonian Center for Astrophysics
60 Garden Street, Cambridge, MA 02138 USA
Phone: 617.496.7941 Fax: 617.495.7356


Text Size:
normal font large font larger font
Chandra X-ray Center, Operated for NASA by the Smithsonian Astrophysical Observatory
This site was developed with funding from NASA under Contract NAS8-39073.
Revised: January 29, 2008