what is the evidence that universe is 13.7B years old?

PeterDona said:

Thanks for putting all this together. I understand that the age of universe, as we are discussing in this thread, is based on the BB model. So you have done a good job of condensing the material, and at least I for one am able to understand the material presented here.

I do not really have any criticism if you would so want. I am trained in molecular biology, not astronomy or particle physics. It is a model put together based on particle physics and the redshift, and as you now mention, emission spectra.

2 questions, if you would be willing to do a little more work:
1) on what basis did George Gamow predict the background radiation? Where would that radiation supposedly come from?
2) Did you find out about the question of radiometric dating of earth? Was there a special finding to that effect?

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Thank-you for your reply. In answer to your two questions:

1) The prediction of the microwave background radiation comes from the fact that according to the Big Bang cosmology the universe has expanded and cooled from a high-density and high-temperature state of an opaque incandescent plasma. When the universe became cool enough (T ~ 3000 K) for ions and electrons to combine to form atoms (abut 380,000 years after the Big Bang), the universe became transparent, and the radiation emitted at this time was able to propagate freely through space. As the universe continued to expand, this radiation was redshifted from the visible region of the spectrum to the microwave region, where Penzias and Wilson discovered it in 1965.

2) Radiometric dating is not really relevant to measurement of the age of the universe. The fact that radiometric dating of terrestrial rocks and meteorites yields an age of 4540 million years for the Earth and an age of 4568 million years for the solar system shows that the universe must be older, but measurements of the age of the universe do not depend on radiometric dating.

PeterDona said:

Richard Dawkins (click) encourages his listeners to go out and actively charge / confront catholics about their core beliefs. Wow.

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PeterDona said:

As regards atheism being not a philosophy, I heard this so many times on the street when I was out evangelising.

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Seems to me like you think it's ok to actively confront people about their core beliefs, so what's the problem?

ximmix said:

Seems to me like you think it's ok to actively confront people about their core beliefs, so what's the problem?

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I encourage active confrontation, but it can go downhill in a hurry.

PeterDona said:

yes, so, this may be it and not much more (?)
Calculating back from observing the rate of expansion of the universe at the present point, again derived from observing the red shift.
It was just, that when I worked on my graduate thesis 25 years ago, one of my fellow thesis students said that scientists from many fields had come together and agreed that the universe is those 13.8 billion years old. It may actually be an urban legend of some kind then.

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The observations on which the 13.7-billion-year age of the universe is based were obtained by the Wilkinson Microwave Anisotropy Probe, which was launched in 2001 and continued its observations until 2010. The first paper based on these observations that gave an age for the universe is by D.N. Spergel et al. (2003), 'First-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters - First-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters . This paper gave an age of 13.7±0.2 billion years for the universe.

As you will see, this paper was published 19 years ago, not 25 years, but, after all, we all make mistakes. It looks as if your fellow student had picked up a garbled version of the research and had got the WMAP age of the universe correct, but had misunderstood how it had been measured.