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Name: Mark
Status: other
Grade: 9-12
Location: Outside U.S.
Country: Australia
Date: N/A

On the question of the 'Age versus size of the universe. An explanation is given that the big bang formed the universe at nearly it's current size. This would need to assume velocity greater than the speed of light in the primordial soup? It is claimed that if we view light of distant objects we will see the universe as it was at the big bang. Since the light from the big bang should be much faster than its expansion it should have passed us a long time ago and exist only at the edge of the universe Is the following assumption correct? If the universe was 10billion years old and the rate of expansion of the radius is 0.1C then the current radius would be 1 billion light years. At 9.0909 billion years the radius would be 0.90909 bly. light from an object would take 0.90909 Bly to reach earth which is a total of 10 billion years. Therefore the farthest object which could be seen should be 0.90909bly From this a formula can be derived. the age of the universe is given as = t0 the velocity of the increase in the radius of the universe = v the radius of the universe at time t0 = r0 the viewed most distant object or apparent radius = r1 time taken for r1 to reach it's position = t1 then t1= t0/v+1 and r1=t0- t1

Dear Mark,

Excellent question. However, most of its parameters are wrong! The explanation that the big bang formed the Universe at nearly its current size is wrong; if the Big Bang theory is correct the Universe has been expanding ever since the Big Bang. When we view light from distant objects we see the universe not as it was at its birth, but a particular object at the distance of that particular object. In simple terms, we see the Andromeda galaxy as it was 2 million years ago, not at the Big Bang when M31 did not even exist. (However, relativity would mean that since light is travelling at the speed of light, the passage of time would not be experienced along the way.) The Universe is not 10 billion years old, according to the WMAP satellite it is 13.7 billion years old. I do dot understand your math at the end; sorry!

I hope these words help clarify things.


David H. Levy

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