Dark matter illuminated
August 28, 2008 | 10:30 am
by Steve Allen and Maruša Bradač
A new study reveals clear evidence of dark matter (blue), separated from ordinary, luminous matter (red) by a merger of galactic subclusters. (Photo courtesy of Maruša Bradač.)
A new study of an immense cosmic collision has provided confirming evidence for dark matter. Our team analyzed the mass content of the enormous, merging galaxy cluster MACSJ0025.4-1222 using the Hubble and Chandra Space Telescopes to disentangle dark and normal matter—that is, matter made up of baryons, common subatomic particles such as protons and neutrons. The new results confirm those obtained from the 2006 study of the Bullet Cluster, providing a clear view of dark matter, separated from ordinary baryons.
The study examines the aftermath of a merger between two giant sub-clusters, each a whopping million billion times the mass of the sun. As these collided at millions of miles per hour, most of the normal, baryonic matter in each—in the form of hot, X-ray emitting gas—interacted with the similar matter in the other and slowed down, like a diver encountering the water’s surface. In contrast, the dark matter did not interact significantly and passed through without disruption. This difference caused the dark matter to sail ahead, leaving the X-ray luminous, baryonic matter lagging behind.
We used high-resolution optical images from Hubble to infer the distribution of total mass through a phenomenon known as gravitational lensing, in which the otherwise invisible dark matter bends light from galaxies in the background. We used Chandra’s high-resolution X-ray images to map the position of the baryons. The observations show a clear separation between the dark and X-ray luminous, baryonic matter, providing direct evidence for dark matter and supporting the view that dark matter particles interact only very weakly, through gravity but little else.
For a closer look:
See animations of a cluster collision from the Chandra Web site (QuickTime or MPEG) and from SLAC (.mov file).
Read the news release from HubbleSite News Center.
This story first appeared in SLAC Today on August 28, 2008.
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4 Comments »
August 28th, 2008 at 2:53 pm
[...] to interrupt my surf week to draw attention to some important news .. there is news on the Symmetry Breaking blog that strong evidence for Dark Matter has just been announced by NASA’s Hubble Space Telescope [...]
September 1st, 2008 at 8:50 am
Surfing and Particle Astrophysics go together like a horse and carriage.
N
October 22nd, 2009 at 7:52 am
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September 13th, 2010 at 1:10 am
Dark matter reactions are reactions that occur out side of photons. call them whatever you want baryons if you must. even if it is producing potential energies of many billions of suns then why is it dark? we think that just because it is empty or black stuff means that there is nothing there. think of what your seeing as a displacing ‘effect’ of a reaction that travels in all directions through multispectral dynamic and multigravidic constants in essence something that is in a state of variance that was moving faster than light in essence outside your perceivable spectrum. regardless of what you looked at was a massive reaction with no source of mass many times more powerful than the sun itself. so one must conclude if a massive reaction of energy at that magnitude can be maintained that oddly seems more evolved than our sun or more efficient in energy production from mass displaced. if a point in the universe could exist moving faster than light itself what would the effects be? spectroscopic analysis would be useless out side of the visible light spectrum. a point in the universe where faster than light speeds were possible at the cost of zero mass would be the most efficient place in the universe to live. but the human body is composed of matter to move faster than light itself the mass inside your body would momentarily displace but when put back together all the connection points be severed like going through a fine molecular sieve. dark matter is white not black because faster than light particles would be located within a fused colored spectrum of multichromatic adherence strands in a particulate coalescing isogrid along series of 12 sided dodecwatchamagons. the confinement to the unperceivable wall of inertia that contains this one tiny little small universe to be included with all the other junk that composes all the primary existence layers in preceptualised dualistic adhesion strands.