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Name:   Jean D.
Status:   educator
Age:   50s
Location: N/A
Country: N/A
Date: 1999 - 2000

If light travels through space, why is space dark? This is a question that has been around for centuries. It is attributed to an astronomer Heinrich Olbers, and bears the name Olbers' (sometimes called Olber's) paradox. Your inquiry motivated me to do a web search -- I thought the answer was simple, I was missing something obvious, and a quick refresher would supply a profoundly simple answer. I was badly mistaken!

The paradox arises by assuming 1. The universe is an infinite Euclidian space. 2. The age of the universe is infinite. 3. Matter is uniformly distributed. 4. The universe is static.

The terms "infinite" and "static" not literally, but sufficiently large to be approximated by these terms. None of these assumptions is exactly true and some "explanations" just say the assumptions are wrong therefore there is no paradox. Sorry, but that is just avoiding the issue. It is clear that we do not "see" all the radiation in the universe and if we could see everything from cosmic rays to microwaves, the sky would be uniformly bright, but that too is only a conjecture because at the present time we cannot "see" all the radiation in the universe at all wavelengths (energies). Ronald Koster has proposed a resolution which may be correct, that says that we are shielded from radiation originating very far away and gives a simple calculation that he contends resolves the paradox, but I'm not an astrophysicist, so I am not able to assess the correctness of his arguments.

I will be interested to see what other Newton BBS responders have to say about this, too. I do not think the answer is simple.

Vince Calder

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