dark matter tagged posts

Taking the Temperature of Dark Matter

Astronomical image
This image from the Hubble Space Telescope shows lensing of distant galaxies by gravity. UC Davis astronomers are using this phenomenon to learn more about the properties of dark matter.

Warm, cold, just right? Physicists at the University of California, Davis are taking the temperature of dark matter, the mysterious substance that makes up about a quarter of our universe.

We have very little idea of what dark matter is and physicists have yet to detect a dark matter particle. But we do know that the gravity of clumps of dark matter can distort light from distant objects. Chris Fassnacht, a physics professor at UC Davis and colleagues are using this distortion, called gravitational lensing, to learn more about the properties of dark matter.

The standard model for dark matter is ...

Read More

Dark Matter may be Older than the Big Bang

cosmic inflation model
(Drbogdan/Yinweichen/Wikimedia Commons)

Dark matter, which researchers believe make up about 80% of the universe’s mass, is one of the most elusive mysteries in modern physics. What exactly it is and how it came to be is a mystery, but a new Johns Hopkins University study now suggests that dark matter may have existed before the Big Bang. The study, published August 7 in Physical Review Letters, presents a new idea of how dark matter was born and how to identify it with astronomical observations.

“The study revealed a new connection between particle physics and astronomy. If dark matter consists of new particles that were born before the Big Bang, they affect the way galaxies are distributed in the sky in a unique way...

Read More

Planck reveals link between Active Galaxies and their Dark Matter environment

Gravitational deflection by quasar-hosting dark matter halos. Credit: David Tree, Professor Peter Richardson, Games and Visual Effects Research Lab, University of Hertfordshire

Scientists have used the tiny distortions imprinted on the cosmic microwave background by the gravity of matter throughout the universe, recorded by ESA’s Planck satellite, to uncover the connection between the luminosity of quasars – the bright cores of active galaxies – and the mass of the much larger ‘halos’ of dark matter in which they sit. The result is an important confirmation for our understanding of how galaxies evolve across cosmic history.

Most galaxies in the universe are known to host supermassive black holes, with masses of millions to billions of times the Sun’s mass, at their cores...

Read More

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...

Read More