dark matter tagged posts

Dark Matter is Not Made Up of Tiny Black Holes

The Milky Way galaxy (left) and the Andromeda galaxy (right) are separated by 2.6 million light years. Compared with the areas where stars are clustered together, dark matter is believed to be distributed over a much larger volume.
Credit: Kavli IPMU

An international team of researchers has put a theory speculated by the late Stephen Hawking to its most rigorous test to date, and their results have ruled out the possibility that primordial black holes smaller than a tenth of a millimeter make up most of dark matter. Details of their study have been published in this week’s Nature Astronomy.

Scientists know that 85% of the matter in the Universe is made up of dark matter. Its gravitational force prevents stars in our Milky Way from flying apart...

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Dark Matter may be Hitting the Right Note in Small Galaxies

Astronomers observed that the dark matter does not seem to clump very much in small galaxies, but their density peaks sharply in bigger systems such as clusters of galaxies. It has been a puzzle why different systems behave differently.
Credit: Kavli IPMU – Kavli IPMU modified this figure based on the image credited by NASA, STScI

Dark matter may scatter against each other only when they hit the right energy, say researchers in Japan, Germany, and Austria in a new study. Their idea helps explain why galaxies from the smallest to the biggest have the shapes they do.

Dark matter is a mysterious and unknown form of matter that comprises more than 80 per cent of matter in the Universe today...

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Hyper Suprime-Cam survey Maps Dark Matter in the universe

The weak lensing surveys such as HSC prefer a slightly less clumpy Universe (left) than that predicted by Planck (right). The pictures show the slight but noticeable difference as expected from large computer simulations. Credit: Hyper Suprime-Cam Survey

The weak lensing surveys such as HSC prefer a slightly less clumpy Universe (left) than that predicted by Planck (right). The pictures show the slight but noticeable difference as expected from large computer simulations.
Credit: Hyper Suprime-Cam Survey

An international group of researchers, including Carnegie Mellon University’s Rachel Mandelbaum, has released the deepest wide field map of the 3D distribution of matter in the universe ever made and increased the precision of constraints for dark energy with the Hyper Suprime-Cam survey (HSC).

The present-day universe is a pretty lumpy place...

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How might Dark Matter interact with Ordinary Matter?

Photo shows PandaX, a xenon-based detector in China. Credit: PandaX.

Photo shows PandaX, a xenon-based detector in China.
Credit: PandaX.

An international team of scientists that includes University of California, Riverside, physicist Hai-Bo Yu has imposed conditions on how dark matter may interact with ordinary matter – constraints that can help identify the elusive dark matter particle and detect it on Earth.

Dark matter – nonluminous material in space – is understood to constitute 85% of the matter in the universe. Unlike normal matter, it does not absorb, reflect, or emit light, making it difficult to detect. Physicists are certain dark matter exists, having inferred this existence from the gravitational effect dark matter has on visible matter. What they are less certain of is how dark matter interacts with ordinary matter – or even if it does.

In the s...

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