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Mon Nov 11, 2019, 12:24 AM

Gamma ray study recalculates rate of expansion of the universe

By Michael Irving
November 10, 2019

Scientists generally agree that the universe is expanding, and that the rate of expansion is accelerating, but exactly how fast that’s happening is up for debate. Now, astrophysicists at Clemson University have come up with a new figure for this measure – called the Hubble Constant – by studying how gamma rays interact with the background radiation of the universe.

The Hubble Constant is named after Edwin Hubble, the astronomer who first discovered that the universe is expanding. Einstein himself had actually found this in earlier equations, but assumed he was wrong and rejigged his calculations to model a static universe. He soon conceded to Hubble, calling the assumption his greatest ever blunder.

In 1929, the first number Hubble attributed to his Constant was 500 km per second per megaparsec (km/s/Mpc) (310.7 mi/s/Mpc), where a megaparsec is about 3.26 million light-years. Basically, that means that more distant galaxies are moving away from us at faster speeds than those closer by. Since then, the Hubble Constant has been constantly refined, and in the last 20 years or so many different methods of measuring it have placed it at around 70 km/s/Mpc (43.5 mi/s/Mpc).

And now, the Clemson team has arrived at a new figure: 67.5 km/s/Mpc (41.9 mi/s/Mpc). The team came to this conclusion by analyzing data from the Fermi Gamma ray Space Telescope and Imaging Atmospheric Cherenkov Telescopes, to determine how gamma rays from distant sources are interacting with the “fog” that permeates the universe.


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Reply Gamma ray study recalculates rate of expansion of the universe (Original post)
Judi Lynn Nov 11 OP
SonofDonald Nov 11 #1

Response to Judi Lynn (Original post)

Mon Nov 11, 2019, 01:14 AM

1. Thank you

You consistently bring the coolest things

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