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Astronomers Measure Total Starlight Emitted Over 13.7 Billion Years (theguardian.com)
Astronomers have measured all the light from all the stars that have ever existed. "In total, the astronomers estimate, stars have radiated 4x1084 photons (a photon being the smallest unit of light)," reports The Guardian. "Or put another way: 4,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 photons." From the report: The astronomers based their calculation on measurements of the extragalactic background light (EBL), a cosmic fog of radiation that has been accumulating since stars first illuminated the dark, vast expanse of space. More than 90% of starlight ends up surviving in this dim backdrop of radiation. The latest observations, collected over nine years by Nasa's Fermi space telescope, use the light from blazars -- super-massive black holes that emit powerful jets of gamma rays -- as beacons to illuminate the cosmic fog.
In total, the team captured signals from 739 blazars -- some relatively close and some extremely distant, whose light was emitted in the ancient universe and has taken billions of years to arrive at Earth. Gamma-ray photons travelling through a fog of starlight have a high chance of being absorbed. So by taking blazars at different distances from the Earth and working out how much of their radiation had been lost along the way, the total starlight at different time periods could be ascertained. The researchers used a computer model to factor in the cosmic fog, which "is simultaneously being diluted as the universe expands and space itself is stretched out," the report mentions. "The measurements suggest that star formation peaked about 11 billion years ago and has been on the wane ever since. About seven new stars are created in our Milky Way galaxy every year."
In total, the team captured signals from 739 blazars -- some relatively close and some extremely distant, whose light was emitted in the ancient universe and has taken billions of years to arrive at Earth. Gamma-ray photons travelling through a fog of starlight have a high chance of being absorbed. So by taking blazars at different distances from the Earth and working out how much of their radiation had been lost along the way, the total starlight at different time periods could be ascertained. The researchers used a computer model to factor in the cosmic fog, which "is simultaneously being diluted as the universe expands and space itself is stretched out," the report mentions. "The measurements suggest that star formation peaked about 11 billion years ago and has been on the wane ever since. About seven new stars are created in our Milky Way galaxy every year."
I counted 156 more than that Maybe time for a recount
The headlines says they measured it, but then the summary says they estimated it.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
So you think astronomers built an apparatus capable of measuring every photon emitted over the last 13.7 billion years? Title of this article is so incorrect editors should go back to primary school.
You can never know everything, and part of what you do know will always be wrong. Perhaps even the most important part.
Just think, if they hadn't published this paper, we might not have known, to a high degree of accuracy, the exact number of photons emitted over the lifetime of the universe.
I can't decide whether this trumps Ugg's famous theorem that striking pieces of flint together summons the fire element from the Fire God in the Sky.
Something cannot come from nothing. It has to come from something else.
That's not how it works. That's not how any of this works.
First of all, something comes from nothing all the time. Quantum fluctuaton creates pairs of something from nothing. Most of these disappear extremely quickly, but due to location being a probability, not a fact, a few must by necessity survive. Our whole universe may be no more than the result of a single vacuum fluctuation, see inflationary theory.
Secondly, "come from" implies time. The concept of time itself breaks down near singularities, making the rule of "something must come from nothing" meaningless in that context. "What was before big bang?" requires a definition of "before" that doesn't imply time ticking or having an arrow.
90% of photons from stars end up in a fog. Ok. And that fog absorbs gamma rays. What kind of fog is that? Photons don't absorb photons, do there must be other matter involved.
From the actual article in Science: "Gamma rays with sufficient energy can annihilate when they collide with EBL photons and produce electron-positron pairs (i.e., the reaction e+e–), effectively being absorbed as a result of the interaction." So yes they do, under the right conditions.
Starships were meant to fly, Hands up and touch the sky - Nicky Minaj
10^84 = 10^42 * 10^42
Coincidence? I think not
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