Olbers Paradox empirically resolved

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brian livesey
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Olbers Paradox empirically resolved

Post by brian livesey »

Another first for the Hubble Space Telescope. Two-hundred years ago, German astronomer Heinrich Olbers posed the question: If there are an infinite number of stars in the sky, why is the sky dark at night? Every available space must be covered by a star, so the sky could never be dark. Olbers suggested that clouds of hydrogen were blocking the light.
Later, astronomers estimated that there were 100 to 200 billion galaxies in the observable universe, but not enough to fill the sky completely. After using Hubble, it's now been calculated that there are two to three trillion galaxies.
Professor Christopher Conselice, an astrophysicist at Nottingham University, who took part in the Hubble study, said: "The extra factor of 10 or more [ galaxies ] is enough to fill in the sky with stars. But most of that light, or all of the light from the most distant galaxies, is being absorbed by hydrogen gas which is between us and them. That was one of the ideas Mr. Olbers had suggested and we brought that back as a solution."
By examining the spectrum of light, "We just didn't know there were galaxies behind the hydrogen wall," said the Professor.
Last edited by brian livesey on Mon Jan 23, 2017 5:41 pm, edited 1 time in total.
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David Frydman
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Re: Olbers Paradox empirically resolved

Post by David Frydman »

The problem is that when scientists claim to know more or less everything, another factor of ten appears.
This sort of thing will happen for as long as we are around.
We will never know everything.

Regards,
David
brian livesey
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Re: Olbers Paradox empirically resolved

Post by brian livesey »

Imagine how monotonous life would be David, if we did know everything. Thank goodness there are always gaps in knowledge to keep us on our toes :wink: .
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Cliff
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Re: Olbers Paradox empirically resolved

Post by Cliff »

Dear Brian
Olbers Paradox is one of several astronomical puzzles that frustrated me over the years. I vaguely recall being quite happy with the first account of Olbers Paradox I read (but can't remember when ?). Unfortunately after that I seemed to occasionally read more thorough explanations involving redshift, the expansion of the universe, & eventually dark matter and dark energy, that confused me. So when I subsequently saw anything about the infamous paradox, I tended to quickly glance through it and pretend I understand it. However, amongst other things I gather the subject of -"why is the night sky dark" was written about by Tommy Digges in 1576. But Olbers didn't say a dicky bird about it until until 1823.
Best wishes from Cliff
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