New dark matter map
Dark matter is a mysterious invisible substance that makes up most of the matter in our universe. We can’t see it, but scientists have been able to infer dark matter’s presence and to study it. Now, scientists have produced the most detailed ever dark matter map, showing the distribution of dark matter, as seen from about a quarter of the night sky visible from Earth’s Southern Hemisphere. The scientists are part of the Dark Energy Survey, a collaboration of more than 400 scientists from 25 institutions in seven countries. They used artificial intelligence, or AI, to analyze images of 226 million galaxies in the southern sky.
The map depicts all the dark matter detected in the foreground of those galaxies.
The new map helps to confirm some predictions of what astronomers call the Standard Cosmological Model, the simplest model so far that explains what’s observed in our universe. But not all the results were anticipated. Surprisingly, there were hints that the universe is smoother than expected.
These scientists announced the new map via Fermilab on May 27, 2021. The scientific results were published May 27 in the peer-reviewed Monthly Notices of the Royal Astronomical Society. There are now 26 published papers from the Dark Energy Survey, of an anticipated 30 interconnected papers to come by the project’s end.
What is dark matter?
The existence of dark matter sounds mysterious and weird … and so it is. Basically, dark matter is matter that we can’t see visually. It doesn’t emit, reflect or absorb light or any other type of electromagnetic radiation such as X-rays or radio waves. Astronomers know it’s there because they see its effects on its surroundings. For example, they “see” dark matter in galaxies that stay clustered together or galaxies within clusters that move faster than expected. In both of those examples, dark matter’s gravitational effects can be measured, though the dark matter itself can’t be seen.
Ordinary matter makes up only about 5% of the universe. Dark energy, which cosmologists hypothesize drives the accelerating expansion of the universe by counteracting the force of gravity, accounts for about 70%. The last 25% is dark matter, whose gravitational influence binds galaxies together.
How did these astronomers study dark matter?
The scientists’ analysis of photographs of the southern sky showed the location and distribution of galaxies in that part of the sky. Since dark matter and galaxies go hand-in-hand, the arrangement of the galaxies shows astronomers where the largest concentrations of dark matter are located.
Also, just like regular matter, dark matter can curve space-time. In the Dark Energy Survey, scientists found dark matter by looking at the light coming from distant galaxies. Often, that light was seen to be distorted or bent more than what the foreground matter could account for. That meant there must be invisible matter bending the light’s path as it…
Read More News: EarthSky | Scientists release best-ever dark matter map