New Study Finds Clumps and Streams of Dark Matter in the Milky Way

By Nancy Atkinson - August 6, 2008 at 7:02 PM UTC | Milky Way
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[/caption] One of the leading theories for how the universe evolved after the Big Bang is the Cold Dark Matter Theory (CDM). This theory proposes that chilly dark matter moved slowly in the early universe, allowing matter to clump together to form the clusters of galaxies that we see, instead of matter being distributed evenly across the universe. Using the properties of the CDM theory, astronomers recently ran an intensive computer program using one of the world's most powerful supercomputers to simulate the halo of dark matter that envelopes our galaxy. The simulation revealed dense clumps and streams of the mysterious dark matter lurking within our Milky Way galaxy, including the region of our solar system.

"In previous simulations, this region came out smooth, but now we have enough detail to see clumps of dark matter," said Piero Madau, professor of astronomy and astrophysics at the University of California, Santa Cruz.

This simulation, detailed in an article in the journal

Nature

, may help may help scientists figure out what dark matter actually is. So far, it has been detected only through its gravitational effects on stars and galaxies. Another part of the CDM theory says that dark matter consists of weakly interacting massive particles (WIMPs), which can annihilate each other and emit gamma rays when they collide. Gamma rays from dark matter annihilation could be detected by the recently launched Gamma-ray Large Area Space Telescope (GLAST).

"That's what makes this exciting," Madau said. "Some of those clumps are so dense they will emit a lot of gamma rays if there is dark matter annihilation, and it might easily be detected by GLAST."

If so, it would be the first direct detection of WIMPS.

Although the nature of dark matter remains a mystery, it appears to account for about 82 percent of the matter in the universe. The clumps of dark matter created "gravitational well" that draws in ordinary matter, giving rise to galaxies in the centers of dark matter halos.

Using the Jaguar supercomputer at Oak Ridge National Laboratory, the simulation took about one month to run and simulated the distribution of dark matter from for 13.7 billion years â€" from near the time of the Big Bang until the current epoch. Running on up to 3,000 processors in parallel, the computations used about 1.1 million processor-hours.

Source:

PhysOrg

Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com