ScienceIQ.com: Cool science facts delivered daily to your email


 Facts By Category:


 » Physics
 » Astronomy
 » Chemistry
 » Biology
 » Mathematics
 » Geology
 » Engineering
 » Medicine
 » Science

  by keyword search:

    
 ScienceIQ Team:


 »Writers & Editors



xUmp.com
Science Supplies,
Toys & Gifts

PhysLink.com
Physics & Astronomy
Online
Dark Matter Mystery


Hot Gas Clouds While carefully measuring the speed of rotation of galaxies, astronomers stumbled upon a profound cosmic mystery. Determining the gravity of the galaxy. They could estimate what the rotation speed should be by calculating the mass of all the visible stars and gas, thereby determining the gravity of the galaxy. Much to their surprise, the measurements showed that most galaxies are rotating faster than they should. Not a little faster. Much faster! More than twice as fast. This meant that, according to Einstein's theory of gravity, these galaxies should be flying apart. Yet clearly, they are not.

What can the answer be? Is it possible that most galaxies are surrounded by some 'dark' form of matter that cannot be observed by radio, infrared, optical, ultraviolet, X-ray, or gamma-ray telescopes? Could Einstein's theory of gravity, which has proved to be correct in all cases so far, be somehow wrong?

X-ray telescopes have discovered vast clouds of multimillion degree gas in clusters of galaxies. These hot gas clouds increase the mass of the cluster, but not enough to solve the mystery. In fact they provide an independent measurement of dark matter. The measurement shows that there must be at least four times as much dark matter as all the stars and gas we observe, or the hot gas would escape the cluster.

185

Fact Credit:
Chandra X-Ray Observatory Center
Chandra Web Site

Further Reading
Dark Matter, Missing Planets and New Comets: Paradoxes Resolved, Origins Illuminated
by Tom Van Flandern


Related Web Links
A Primer on Dark Matter
by Mike Guidry

Mysterious Dark Matter
by University of Illinois





Home | Privacy Policy

Copyright © 2002-2017 ScienceIQ.com - All Rights Reserved