"Evidence of Dark Matter Will be Found Near the Sun" The Daily Galaxy --Great Discoveries Channel: Sci, Space, TechFollow the Daily Galaxy
« Curiosity's First Long-Range & Panoramic Images |Main| Image of the Day: Carl Sagan's Childhood Drawing of His Vision of Outer Space »August 09, 2012 "Evidence of Dark Matter Will be Found Near the Sun"
"We are 99% confident that there is dark matter near the Sun," says the lead author Silvia Garbari of the University of Zurich. "This could be the first evidence for a "disc" of dark matter in our Galaxy, as recently predicted by theory and numerical simulations of galaxy formation, or it could mean that the dark matter halo of our galaxy is squashed, boosting the local dark matter density."
Dark matter was first proposed by the Swiss astronomer Fritz Zwicky in the 1930s. He found that clusters of galaxies were filled with a mysterious dark matter that kept them from flying apart. At nearly the same time, Jan Oort in the Netherlands discovered that the density of matter near the Sun was nearly twice what could be explained by the presence of stars and gas alone.In the intervening decades, astronomers developed a theory of dark matter and structure formation that explains the properties of clusters and galaxies in the Universe, but the amount of dark matter in the solar neighbourhood has remained more mysterious. For decades after Oort's measurement, studies found 3-6 times more dark matter than expected. Then last year new data and a new method claimed far less than expected. The community was left puzzled, generally believing that the observations and analyses simply weren't sensitive enough to perform a reliable measurement.
An international team lead by researchers of the University of Zürich used a state-of-the-art simulation of the Milky Way to test their mass-measuring method before applying it to real data. This threw up a number of surprises: they noticed that standard techniques used over the past twenty years were biased, always tending to underestimate the amount of dark matter.
The researchers then developed a new unbiased technique that recovered the correct answer from the simulated data. Applying their technique to the positions and velocities of thousands of orange K dwarf stars near the Sun, they obtained a new measure of the local dark matter density.
Many physicists are placing their bets on dark matter being a new fundamental particle that interacts only very weakly with normal matter, but strongly enough to be detected in experiments deep underground. An accurate measure of the local dark matter density is vital for such experiments.
"If dark matter is a fundamental particle, billions of these particles will have passed through your body by the time your finish reading this article, said lead author George Lake."Experimental physicists hope to capture just a few of these particles each year in experiments like XENON and CDMS currently in operation. Knowing the local properties of dark matter is the key to revealing just what kind of particle it consists of."
Source: Silvia Garbari, Chao Liu, Justin I. Read, George Lake. A new determination of the local dark matter density from the kinematics of K dwarfs. Monthly Notice of the Royal Astronomical Society. 9 August, 2012. 2012arXiv1206.0015G.
The Daily Galaxy via University of Zurich
Posted at 09:00 AM | PermalinkComments
“The amount of mass that we derive matches very well with what we see — stars, dust and gas — in the region around the Sun,” says team leader Christian Moni Bidin (Departamento de Astronomía, Universidad de Concepción, Chile). “But this leaves no room for the extra material — dark matter — that we were expecting. Our calculations show that it should have shown up very clearly in our measurements. But it was just not there!”
http://www.eso.org/public/news/eso1217/
Posted by:orkneylad |August 09, 2012 at 09:52 AMWhy don't they just call it invisible matter? For all we know it just might be matter in a parallel universe existing right on top of us.
Posted by:Paul |August 09, 2012 at 10:44 AMedelweiss dark matter experiment, i was speaking to two brothers sat in a sauna while i was snowboading in austria, they work for this project, they have found so much dark matter in far away constellations they are like huge planets but could pass through each other, and finding more and more all the time, they know its there because its gravitational pull bends light slightly around it, interesting stuff :)
Posted by:dave |August 09, 2012 at 03:43 PMI am always wondering if the so called dark matter is actually the same thing like the light we know?
Our universe is filled with light( many types though )everywhere. But we can not see the light unless it comes straight to us.
Sounds strange , but light is dark matter ( invisible ) to me.
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