by Mitch Battros – Earth Changes Media

Astronomers using data from NASA’s Fermi Gamma-ray Space Telescope have made the most accurate measurement of starlight in the universe and used it to establish the total amount of light from all the stars that have ever shone, accomplishing a primary mission goal. A paper describing the findings was published Thursday on Science Express.

 

 

As matter falls toward a galaxy’s supermassive black hole, some of it is accelerated outward at almost the speed of light in jets pointed in opposite directions. When one of the jets happens to be aimed in the direction of Earth, the galaxy appears especially bright and is classified as a blazar.

 

“The Fermi result opens up the exciting possibility of constraining the earliest period of cosmic star formation, thus setting the stage for NASA’s James Webb Space Telescope,”said Volker Bromm, an astronomer at the University of Texas, Austin, who commented on the findings. “In simple terms, Fermi is providing us with a shadow image of the first stars, whereas Webb will directly detect them.”

 

Gamma rays are the most energetic form of light. Since Fermi’s launch in 2008, its Large Area Telescope (LAT) observes the entire sky in high-energy gamma rays every three hours, creating the most detailed map of the universe ever known at these energies.

 

“The optical and ultraviolet light from stars continues to travel throughout the universe even after the stars cease to shine, and this creates a fossil radiation field we can explore using gamma rays from distant sources,” said lead scientist Marco Ajello, a postdoctoral researcher at the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University in California and the Space Sciences Laboratory at the University of California at Berkeley.

 

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