- 3510 - DARK MATTER GALAXIES - constructing a picture? Astronomers claim they have captured an image of dark matter. This is a connection point in the great cosmic web in which our universe’s billions of galaxies are thought to be embedded. Seems counterintuitive to image something we cant see?
--------- 3510 - DARK MATTER GALAXIES - constructing a picture?
- Their research confirms predictions that galaxies across the universe are tied together through a cosmic web connected by dark matter that has until now remained unobservable. Dark matter filaments bridge the space between galaxies.
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- Dark matter holds an honored place in astronomical theory; it’s an integral part of the “Lambda Cold Dark Matter model”, the standard model of Big Bang cosmology. This is a widely accepted model of how our universe works and a model that agrees well with what astronomers believe they see, when they look out into deep space.
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- Some astronomers think we don’t understand dark matter, or think it doesn’t exist at all. For example, in 2016, physicist Erik Verlinde at University of Amsterdam released the latest installment of his new theory of gravity, in which he said he doesn’t need dark matter to explain the motions of stars in galaxies.
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- Not long afterwards, a team led by astronomer Margot Brouwer of Leiden Observatory in The Netherlands tested Verlinde’s theory by examining the lensing effect of gravity around more than 33,000 galaxies. Her team concluded that Verlinde’s theory “agrees well” with the observations.
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- Of course, the theories and observations are always flawed and imperfect. According to the most accepted theories of the universe, dark energy is thought to contribute 73 % of all the mass and energy in the universe.
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- Another 23 % is dark matter, which leaves only 4 % of the universe composed of regular matter, such as stars, planets and people. Our entire “known universe” is in that small 4%
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- Dark matter, whatever it is, comprises about a quarter of all the “stuff” of our universe. This mysterious substance doesn’t shine, absorb or reflect light, although its effects are thought to be recognizable via the workings of gravity. Dark but massive?
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- According to these theories, dark matter is integral in creating what astronomers call the “cosmic web“, the basic structure of our universe. This great web is thought to consist of a network of filaments of dark matter.
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- For decades, researchers have been predicting the existence of dark-matter filaments between galaxies that act like a web-like superstructure connecting galaxies together.
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- In the “cosmic web.” the bright areas are galaxy clusters and groups, with sparsely populated regions devoid of galaxies in between. Since astronomers believe that galaxies are made in a process whereby dark matter merges and clumps together, and since dark matter is thought to be so much more abundant in our universe than the sort of matter composes stars and galaxies (and planets like Earth, and people like you and me), dark matter is what is thought to drive the cosmic web’s structure.
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- How did astronomers obtain their image of dark matter? They used a technique called “weak gravitational lensing” which is an effect that causes the images of distant galaxies to warp slightly under the influence of an unseen mass such as a planet, a blackhole, or in this case, dark matter. They measured the effect in images from a multi-year sky survey at the Canada-France-Hawaii Telescope on Mauna Kea in Hawaii.
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- They combined lensing images from more than 23,000 galaxy pairs located 4.5 billion light-years away to create this composite image or map, which shows the presence of dark matter between the two galaxies. It’s a dark matter bridge. The dark matter filament bridge is strongest between systems less than 40 million light years apart.
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- By using this technique, we’re not only able to see that these dark matter filaments in the universe exist, we’re able to see the extent to which these filaments connect galaxies together. Astronomers are surrounding dark matter. Maybe we will soon know what it is?
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March 20, 2022 DARK MATTER GALAXIES - constructing a picture? 3510
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