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Scientists have measured all the photons ever produced in the observed universe



Clemson University Astrophysicist Marco Ajello enjoys a spectacular view of the stars on November 20th at Clemson Outdoor Lab. (Credit: University of Pete Martin / Clemson)

Astrophysicist Marco Ajello at Clemson Outdoor Lab. (Credit: University of Pete Martin / Clemson)

Astrophysicists estimate that our universe was born about 13.7 billion years ago, with the first stars forming when the universe was only a few hundred million years ago. Returning to the earliest star-making days, scientists in South Carolina measured all the starry light ever produced throughout the history of the visible universe.

Scientists have been working for a long time to get this measure, also known as extra-galactic background light (EBL) or "cosmic fog". "EBL is a book that reports about star activity and the evolution of the galaxy in the universe," said Marco Ajello, principal investigator and astrophysicist at Clemson College of Science in South Carolina.

Measuring EBL could be a great tool for scientists, helping them better understand the evolution of the galaxy, the staring processes of formation, and how the universe evolved, Ajello explained. But so far, scientists could not make this measurement because the EBL was much smoky than the Milky Way and other nighttime light. Scientists were not able to observe the distant galaxies because they were too weak and the light shining in the foreground further shielded this view. Now, by using an indirect method, scientists have finally made this measurement.

The team found that the amount of light star or the number of photons (visible light particles) emitted by the stars through the history of the visible universe of 4 × 10 ^ 84 photons. Or, alternatively, 4,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000,000,000,000,000,000,000,000 photons.

Indirect measurements

The team has managed to make this stellar measure of observation of blazers or galaxies with super-massive black holes emitting radiation and radiation in our direction using NASA's Fermi Gamma telescope.

"Using the blazers at different distances from us, we measured the total observatory at different time periods. We measured the total star of each epoch – a year ago, two billion years ago, six billion years ago – all the way back to the star. This enabled us to reconstruct the EBL and determine the history of creating stars of the universe in a more efficient way than it was before, "said Vaidehi Paliya, co-author and postdoctoral analyst who analyzed nearly nine years of relevant data. Statement.

Blazers emit nozzles of energy particles that include gamma rays or ultra-energy photons. And gamma rays emitted by blazers travel through cosmic fog (EBL), which consists of a visible and ultraviolet starlight. When the gamma rays collide with visible light, they are transformed into pairs of electrons and positron. "In fact, the process blurs the gamma radiation signal in a similar way to a fog lighter lighthouse," NASA said in a statement on the phenomenon. These collisions leave visible prints that scientists can observe using Fermi.

"Measuring how much photons were absorbed, we were able to measure how thick fog and scale, how much time it was in time, how much light was in the full range of wavelengths," Ajello said in a statement.

By mapping the various densities of this cosmic fog, researchers could observe an extremely distant (and therefore extremely old) starry light as these collisions occur at distant distances. This technique also acted because indirectly by observing the star of light through the interaction between gamma ray and visible light, the technique was not clouded or lightened by light in the first light.

"The first billion years of the history of our universe is a very interesting epoch that has not yet been investigated by the current satellites." "Our measurements allow us to look at it, perhaps one day to find a way to look to the Big Bang." This is our ultimate goal, "Ajello concluded in a statement.

Researchers today released their work in the journal Science.


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