Paranormal Psychic Forums

Psychic paranormal community Forums for like minded individuals who wish to connect, chat and share.

Dark energy survey offers new view of dark matter halos, physicists report

Bringing some of the mysteries of the universe a little closer to home.

User avatar
Owlscrying
Posts: 2063
Joined: Mon Apr 03, 2017 3:21 am

Unread post Sun Dec 17, 2017 11:27 pm

Dark matter, a mysterious form of matter that makes up about 80 percent of the mass of the universe, has evaded detection for decades. Although it doesn't interact with light, scientists believe it's there because of its influence on galaxies and galaxy clusters.

It extends far beyond the reach of the furthest stars in galaxies, forming what scientists call a dark matter halo. While stars within the galaxy rotate in a neat, organized disk, these dark matter particles are like a swarm of bees, moving chaotically in random directions, which keeps them puffed up to balance the inward pull of gravity.

Source

 

User avatar
Owlscrying
Posts: 2063
Joined: Mon Apr 03, 2017 3:21 am

Unread post Sun Dec 17, 2017 11:28 pm

Image
Credit: ESO/L. Calçada

This artist’s impression shows the Milky Way galaxy. The blue halo of material surrounding the galaxy indicates the expected distribution of the mysterious dark matter, which was first introduced by astronomers to explain the rotation properties of the galaxy and is now also an essential ingredient in current theories of the formation and evolution of galaxies.

Source / Image Courtesy

 

User avatar
Owlscrying
Posts: 2063
Joined: Mon Apr 03, 2017 3:21 am

Unread post Sun Dec 17, 2017 11:30 pm



About 80 percent of the matter in the universe is invisible to telescopes, yet its gravitational influence is manifest in the orbital speeds of stars around galaxies and in the motions of clusters of galaxies. Yet, despite decades of effort, no one knows what this "dark matter" really is. Many scientists think it's likely that the mystery will be solved with the discovery of new kinds of subatomic particles, types necessarily different from those composing atoms of the ordinary matter all around us. The search to detect and identify these particles is underway in experiments both around the globe and above it.

WIMPs, or Weakly Interacting Massive Particles, represent a favored class of dark matter candidates. Some WIMPs may mutually annihilate when pairs of them interact, a process expected to produce gamma rays -- the most energetic form of light -- that the LAT is designed to detect.

The team examined two years of LAT-detected gamma rays with energies in the range from 200 million to 100 billion electron volts (GeV) from 10 of the roughly two dozen dwarf galaxies known to orbit the Milky Way. Instead of analyzing the results for each galaxy separately, the scientists developed a statistical technique -- they call it a "joint likelihood analysis" -- that evaluates all of the galaxies at once without merging the data together. No gamma-ray signal consistent with the annihilations expected from four different types of commonly considered WIMP particles was found.

 

User avatar
Owlscrying
Posts: 2063
Joined: Mon Apr 03, 2017 3:21 am

Unread post Sun Dec 17, 2017 11:32 pm



Simulation of dark matter distribution in theorized halo around our galaxy as it is imagined to appear today.

In our currently favored models of the evolution of the Universe, most of the matter in the Universe is not like the stuff that you, I, this computer or the stars are made out of. Instead, it is a substance called dark matter, so-called because it emits no light and can only interact via gravity.

In this model, when the Universe was very young, the dark matter was relatively smoothly distributed throughout the Universe, But this situation couldnt last, because of gravity. Areas of the Universe which had just very slightly more dark matter than other areas exerted stronger gravity, pulling more dark matter towards them and causing them to get bigger, so they exerted even more gravity... this runaway effect caused all of the dark matter to start clumping together, forming what astronomers call "halos" of dark matter.

 

Post Reply

Return to “The Universe”

  • Information
  • Who is online

    Users browsing this forum: No registered users and 4 guests