Astronomers Find Dark Matter From 12 Billion Years Ago
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Loading... - Ibrahim Yakubu
- 18 Aug 2022
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We know dark matter exists — a mysterious substance that is five times as prevalent in the Universe by mass as what we think of as “normal” matter, the stuff you and I and everything we see are made of. We see its effects through its gravity, even though we don’t know what it’s made of yet. Dark matter affects how galaxies rotate, and how they move in gigantic galaxy clusters.
We also see its effects via gravitational lensing. Mass has gravity, which warps space. If we look past some massive object like a galaxy to an even more distant galaxy beyond, the foreground galaxy’s mass warps space, distorting the image of the background galaxy. That more distant galaxy can look smeared, or bent, or even duplicated into multiple images of it. The foreground galaxy’s gravity acts like a lens, hence the name.
We can measure the light coming from the lensing galaxy and measure the mass of its normal matter that way. Then we can measure how much it distorts more distant objects and get its total mass. The difference is how much dark matter it harbors. This method has worked with great success in recent years. Read More...
