Is there dark matter in galaxy clusters?
Examination of huge clusters of galaxies has revealed that dark matter — the invisible stuff that constitutes most of the Universe’s mass — forms more galactic-scale lumps than expected. As expected, most of the lensing power was centred around the clusters’ middle regions, where dark matter forms a dense ‘halo’.
What is the connection between galaxy clusters and dark matter?
Dark matter’s gravity adds to this effect, and galaxy clusters appear to be chock-full of the stuff. According to our best models, not only are galaxy clusters embedded in vast, spherical halos of dark matter but individual galaxies within a cluster also lie within their own dark matter “subhalos.”
How does the Bullet Cluster prove dark matter?
When space is warped by dark matter’s gravity, the light of distant galaxies appears distorted. Multi-wavelength observations of the Bullet Cluster provided the first strong observational evidence that dark matter does not interact with normal matter, or with itself, and holds the majority of mass in a galaxy cluster.
Can dark matter bends light?
Very high concentrations of dark matter can act like a lens to bend light and drastically alter the appearance of background galaxies as seen from Earth — stretching them into arcs or splitting them into multiple images of the same object on the sky.
Is dark matter A neutrinos?
Neutrinos are a form of dark matter, because they have mass, and weakly interact with light. But neutrinos have such a small mass and high energy that they move through the universe at nearly the speed of light. For this reason, they are known as hot dark matter.
What is one important difference between dark matter and dark energy?
Dark matter produces an attractive force (gravity), while dark energy produces a repulsive force (antigravity). Together, they make up 96 percent of the universe—and we can’t see either. Astronomers know dark matter exists because visible matter doesn’t have enough gravitational muster to hold galaxies together.
Is a cluster bigger than a galaxy?
When comparing the two, a typical globular cluster might contain a mass of 100,000 Suns, whereas the Milky Way has nearly 1 trillion solar masses. In other words, the Milky Way Galaxy contains 10 million times more mass than a typical globular cluster.
Why is dark matter inferred to exist because?
Dark matter is inferred to exist because: we can observe its gravitational influence on visible matter. The flat part of the Milky Way’s rotation curve tells us that stars in the outskirts of the galaxy: orbit the galactic center just as fast as stars closer to the center.
What is the difference if any between dark matter and dark energy?
In short, dark matter slows down the expansion of the universe, while dark energy speeds it up. Meanwhile, dark energy is a repulsive force — a sort of anti-gravity — that drives the universe’s ever-accelerating expansion.
Can dark matter cause gravitational lensing?
Dark matter is an invisible form of matter that makes up most of the universe’s mass and creates its underlying structure. Dark matter’s gravity drives normal matter (gas and dust) to collect and build up into stars and galaxies. This phenomenon is called gravitational lensing.
What makes up the dark matter of galaxies?
As far as scientists can tell, a cluster’s real heft lies within a material that can’t be seen: an invisible, mysterious substance called dark matter. Like the concrete and asphalt beneath a city, a vast spherical halo of dark matter undergirds the whole cluster of galaxies.
What kind of mass is found in galaxy clusters?
The mystery mass is dark matter — and galaxy clusters give us some of the strongest clues as to the nature of this mysterious component of the cosmos.
Which is the largest galaxy cluster in the Dark Universe?
Galaxy clusters rule the dark universe. The star cluster Abell 2744, also known as Pandora’s Cluster, as imaged by the Spitzer Space Telescope in infrared. (Image credit: NASA/JPL-Caltech)
