How do we Know the Universe is 14 Billion Years Old?

[Danmark]

One of the fundamental disagreements between some Christians and most Muslims, and also within the religious community, is the age of the Earth and the Universe. My cousin, Peter Slen, senior executive producer of C-Span's Book TV, recently interviewed Neil deGrasse Tyson who walks us thru the process of 'how we know.'

https://www.c-span.org/video/?427009-1/ ... asse-tyson

The subject for debate is the age of the Universe and the Earth and how do we know.

[Kenisaw]

One of the fundamental disagreements between some Christians and most Muslims, and also within the religious community, is the age of the Earth and the Universe. My cousin, Peter Slen, senior executive producer of C-Span's Book TV, recently interviewed Neil deGrasse Tyson who walks us thru the process of 'how we know.'

https://www.c-span.org/video/?427009-1/ ... asse-tyson

The subject for debate is the age of the Universe and the Earth and how do we know.

Wow, a 6 hour video. Don't have time for that now.

As to the question, those two things are kind of tied in together. Meteorites, moon rocks, Earth rocks, and even the age of the Sun help date the solar system as a whole and the Earth in particular. The date of the Earth makes sense separately when considering the age of the universe and what we know about galaxy formation, globular cluster star formation, etc. and the time for those to occur. The date of the universe comes from globular cluster stars, the CMB, the expansion of the universe. The Earth stuff is explained simply at the USGS link below that I have in my favorites.


https://pubs.usgs.gov/gip/geotime/age.html

[Danmark]

Wow, a 6 hour video. Don't have time for that now.

Actually, the information for this topic is in about the first six minutes. The heart of the video is in the first hour at most. Then it gets into a Q&A from viewers. I didn't look at that either. But the first small portion of the video gives a simple, common sense explanation for those not inclined to follow the details of the science.

[Derrrpp]

To my knowledge it is not very accurately known- why not f(a^-1)? If the age of the universe is 13.7035999 billion years then thats not quite the delineation of sunsets we think it is...the last extinction was 13.7035999 million years ago etc ...If some exponential rate of change is occuring then what is the model that supports that and is there any evidence for it? Lets have fun because none here are writing astronomy articles.

[Danmark]

To my knowledge it is not very accurately known- why not f(a^-1)? If the age of the universe is 13.7035999 billion years then thats not quite the delineation of sunsets we think it is...the last extinction was 13.7035999 million years ago etc ...If some exponential rate of change is occuring then what is the model that supports that and is there any evidence for it? Lets have fun because none here are writing astronomy articles.

What do your calculations conclude? How old is the universe and upon what facts do you rely?
The video is merely a simplified explanation. "Astronomers estimate the age of the universe in two ways: 1) by looking for the oldest stars; and 2) by measuring the rate of expansion of the universe and extrapolating back to the Big Bang; just as crime detectives can trace the origin of a bullet from the holes in a wall."
https://map.gsfc.nasa.gov/universe/uni_age.html

If you want to do (or check) the math you may.

If you disagree with the following, please point out the specifics and 'show your work.' If you fault the following, please explain.

An alternative approach to estimating is the age of the universe is to measure the “Hubble constant�. The Hubble constant is a measure of the current expansion rate of the universe. Cosmologists use this measurement to extrapolate back to the Big Bang. This extrapolation depends on the history of the expansion rate which in turn depends on the current density of the universe and on the composition of the universe.
If the universe is flat and composed mostly of matter, then the age of the universe is
2/(3 Ho)
where Ho is the value of the Hubble constant.
If the universe has a very low density of matter, then its extrapolated age is larger:
1/Ho
If the universe contains a form of matter similar to the cosmological constant, then the inferred age can be even larger.

Many astronomers are working hard to measure the Hubble constant using a variety of different techniques. Until recently, the best estimates ranged from 65 km/sec/Megaparsec to 80 km/sec/Megaparsec, with the best value being about 72 km/sec/Megaparsec. In more familiar units, astronomers believe that 1/Ho is between 12 and 14 billion years.

AN AGE CRISIS?

If we compare the two age determinations, there is a potential crisis. If the universe is flat, and dominated by ordinary or dark matter, the age of the universe as inferred from the Hubble constant would be about 9 billion years. The age of the universe would be shorter than the age of oldest stars. This contradiction implies that either 1) our measurement of the Hubble constant is incorrect, 2) the Big Bang theory is incorrect or 3) that we need a form of matter like a cosmological constant that implies an older age for a given observed expansion rate.

Some astronomers believe that this crisis will pass as soon as measurements improve. If the astronomers who have measured the smaller values of the Hubble constant are correct, and if the smaller estimates of globular cluster ages are also correct, then all is well for the Big Bang theory, even without a cosmological constant.

WMAP CAN MEASURE THE AGE OF THE UNIVERSE

Measurements by the WMAP satellite can help determine the age of the universe. The detailed structure of the cosmic microwave background fluctuations depends on the current density of the universe, the composition of the universe and its expansion rate. As of 2013, WMAP determined these parameters with an accuracy of better than than 1.5%. In turn, knowing the composition with this precision, we can estimate the age of the universe to about 0.4%: 13.77 ± 0.059 billion years!

How does WMAP data enable us to determine the age of the universe is 13.77 billion years, with an uncertainty of only 0.4%? The key to this is that by knowing the composition of matter and energy density in the universe, we can use Einstein's General Relativity to compute how fast the universe has been expanding in the past. With that information, we can turn the clock back and determine when the universe had "zero" size, according to Einstein. The time between then and now is the age of the universe. There is one caveat to keep in mind that affects the certainty of the age determination: we assume that the universe is flat, which is well supported by WMAP and other data. If we relax this assumption within the allowed range, the uncertainty increase a bit. Inflation naturally predicts a very nearly flat universe.

The expansion age measured by WMAP is larger than the oldest globular clusters, so the Big Bang theory has passed an important test using data independent of the type collected by WMAP. If the expansion age measured by WMAP had been smaller than the oldest globular clusters, then there would have been something fundamentally wrong about either the Big Bang theory or the theory of stellar evolution. Either way, astronomers would have needed to rethink many of their cherished ideas. But our current estimate of age fits well with what we know from other kinds of measurements.
https://map.gsfc.nasa.gov/universe/uni_age.html

[Derrrpp]

[Replying to post 5 by Danmark]

My post relates to the assumptions that are inherent and admitted to in modeling things- look for a moment at the IFS you mention in the AGE IN CRISIS? section- those are legitmate and relate to what real astronomers are doing with their models. Im not a scientist but I discuss such things with one on a regular basis. Models are what they are and if you arent an astronomer to delineate what they mean then it is sure fire easy enough as an outsider to mistake their intent. Then their models -no matter how well built- have to survive and demonstrate that models like mine cant be the right answer- it is part of the process. If they cant eliminate contenders then anyone can choose favorites. So obviously I think is it very very very difficult for a collective body of laymen to address the OP without real scientists and anticipate that it will boil down to al lot of opinion and favoritism which is why I offered my 'model' up front. Sorry I suppose I will have to wait for telescope time to honestly defend it even though it does fit almost to margin of error for the WMAP age, and the process of how the model functions was asked for and not claimed.

[Danmark]

[Replying to post 5 by Danmark]

My post relates to the assumptions that are inherent and admitted to in modeling things- look for a moment at the IFS you mention in the AGE IN CRISIS? section- those are legitmate and relate to what real astronomers are doing with their models. Im not a scientist but I discuss such things with one on a regular basis. Models are what they are and if you arent an astronomer to delineate what they mean then it is sure fire easy enough as an outsider to mistake their intent. Then their models -no matter how well built- have to survive and demonstrate that models like mine cant be the right answer- it is part of the process. If they cant eliminate contenders then anyone can choose favorites. So obviously I think is it very very very difficult for a collective body of laymen to address the OP without real scientists and anticipate that it will boil down to al lot of opinion and favoritism which is why I offered my 'model' up front. Sorry I suppose I will have to wait for telescope time to honestly defend it even though it does fit almost to margin of error for the WMAP age, and the process of how the model functions was asked for and not claimed.

Fine. So how old do you think the universe is and what is the evidence to support your opinion?

So, you are a non scientist who is talking around the issue by talking about modelling. There is clear consensus among REAL scientists that the universe is about 14 billion years old.

You are not speaking to the issue. You also imply that the rest of us can't know unless we personally look thru telescopes ourselves. This is absurd. Here's a simple explanation of the science and the calculations:

Hubble has helped to measure the age of the universe using two different methods. The first method involves measuring the speeds and distances of galaxies. Because all of the galaxies in the universe are generally moving apart, we infer that they must all have been much closer together sometime in the past. Knowing the current speeds and distances to galaxies, coupled with the rate at which the universe is accelerating, allows us to calculate how long it took for them to reach their current locations. The answer is about 14 billion years. The second method involves measuring the ages of the oldest star clusters. Globular star clusters orbiting our Milky Way are the oldest objects we have found and a detailed analysis of the stars they contain tells us that they formed about 13 billion years ago. The good agreement between these two very different methods is an encouraging sign that we are honing in on the universe’s true age.
http://hubblesite.org/reference_desk/fa ... =cosmology

[Derrrpp]

I offered a competing model. BUT I have thought better of it and discovered an interesting topic more to the point of the OP as requested.

I understand that it is numerology to forward, but it is exactly the ubiquity of the fine structure (a)that the scientists must address. I dont need to prove or defend my model. I think, if Im correct, that they need to defend theirs. In my model the inverse value(a) is the direct link to the age but in theirs the phenomena that are measured to develop the value have been influence by the fine structure constant i.e the electron orbits = the remission lines of visible light. How many parameters and to what degree they influenced by the value of a Im not sure. To that extent I think they do have to prove that the value they obtain is NOT TRIVIAL to the fine structure constant because math can do that. Since we can write a simple proportionality equation between h,c,a,and e then even though Im being a 'numerologist' my criticism is valid. Meaning that it would be obvious if their answer was 39.9752 x 10^9(c) or 4.135x10^9(h). So because it is close, because the fine structure is famously everywhere they do have to prove it. It may only take 2 seconds to do so but Im curious to the process rather than being right or wrong.Is that a legitimate criticism of their model?

[Danmark]

I understand that it is numerology to forward, but it is exactly the ubiquity of the fine structure (a)that the scientists must address. I dont need to prove or defend my model. I think, if Im correct, that they need to defend theirs.
.... even though Im being a 'numerologist' my criticism is valid.
....
Is that a legitimate criticism of their model?

No. It is not legitimate. I find it curious you say 'they' must defend their model [which has been done thousands of times], but you don't have to defend yours.

I agree your explanation involves numerology.

Numerology is any belief in the divine, mystical relationship between a number and one or more coinciding events. It is also the study of the numerical value of the letters in words, names and ideas. It is often associated with the paranormal, alongside astrology and similar divinatory arts.
....
The term numerologist can be used for those who place faith in numerical patterns and draw pseudo-scientific inferences from them, even if those people do not practice traditional numerology.
https://en.wikipedia.org/wiki/Numerology

[Derrrpp]

I dont choose to defend that model ..I changed the nature of my discussion to a criticism of the measurement 13.77+/- .059. I can be a simply acting as a devils advocate noting the familiarity of that value throughout the world of physics as a reason. It becomes trivial because of mathematics not anything about my technique or the fact that Im noting it because of numerology attitudes or biases. Nothing about me or my credentials has anything to do with it. Mathematics is the vehicle and the familairity of the fine structure in other peoples models of other physics phenomena makes it a potential cause for concern that the number is trivial. I dont have to prove it.