Invisible Dark Matter
Photo by Chandra X-ray telescope team.
The Dark Matter Of The Universe Has A Long Lifetime
The two clusters of galaxies, called Bullet Cluster, are in the process of moving through each other. The red curves show gravitational measurements of the combined mass that consists of partly the visible matter of the galaxies and partly the invisible dark matter.
X-ray measurements of the two clusters of galaxies show that the clouds of gas have been pushed out at the collision between the two clusters of galaxies. In the cluster of galaxies to the right there is a lot of dark matter, but very little x-ray, so the dark matter decays very slowly and thus has a very, very long lifetime.
The universe consists not just of visible celestial bodies, stars, planets and galaxies. It also has a mystical fellow player - dark matter. New research from the Niels Bohr Institute presents new information that adds another piece of knowledge to the jigsaw puzzle of the dark mystery of the universe - dark matter.
The research has just been published in the Physical Review Letters: Searching for Decaying Axionlike Dark Matter from Clusters of Galaxies
Astronomers can measure that dark matter exists in big quantities but no one knows what it is, nobody has seen it. It does not emit light and it does not reflect light. It is invisible. It is a mystery and the researchers have many theories.
The dark matter has caused the researchers headaches for decades since it was detected in the 1970s, and there is intense research into the phenomena. It is invisible but it has got mass, and thus it has got gravitation that can be measured.
By analysing the galaxies it is possible to weigh them, and it turns out that by far the greatest matter of the collective mass of the galaxy is dark matter.
Just like stars get together in galaxies, the galaxies get together in clusters of galaxies of up to several thousand galaxies. Signe Riemer-Sorensen, astrophysicist at the Niels Bohr Institute, has analysed two clusters of galaxies that collide.
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