# Age of the Universe

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Hayden, Jul 19, 2018.

1. ### nebel

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The sausage illustrations of the age of the universe all demand an inflationary period after the Big Beginning, and that to explain the smooth temperature range throughout the later universe; but you do not need an explosive growth to have that. Example:
All humans have a common normal temperature of 37 degrees, but the population explosion has only happened late, in the last 100 years. the common origin was the key. and is perhaps to the universes' uniformity too. everything has moved through the same time radius since the beginning.

3. ### Write4UValued Senior Member

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Any accelerating increase (population explosion) is due to the exponential function and is common to anything with a steady percent increase over time. A 1 % steady increase will result in a "doubling time" every 70 years . 2% increase, every 35 years . 5% increase, every 14 years. etc.

5. ### nebel

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In my lifetime, close to 70 + 28 , the population has not doubled , but quadrupled; inflationary growth at the end , not the beginning; whereas the big increase in the universe's volume is supposed to have come at the beginning, just to get the temperature spread right. IMHO, Inflation was not needed, steady, second by second linear growth did it.
My argument was, that common origin can do that too, not only later communication.

7. ### Write4UValued Senior Member

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Yes, steady linear growth of 1 % p/yr of anything will result in a doubling time of 70 years.

This is the equation of the "exponential function" (in banking its known as compound interest) which starts small but rapidly increases in size with each doubling time.

An excellent lecture by Prof. Albert Bartlett (mathematics)

Last edited: Jul 23, 2018
8. ### nebel

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thank you for the graph, I thought it was the accruement banking fees, ha ha. We agree, the human race above is at the (1, vertical line. It took us 3 million years from Lucy, or 6 k form Adam ha ha to get to 2 billion, and in my short life time to 8 billion. only,
The history of the universe projected back was not like that, hence the OP question. It started out fast, inflation to make the sausage casing , or in the expanding sphere model adding 2seconds x3.14 every second doubling in the beginning, now adding almost nothing to the flatness; same with the Hubble constant observations, the further we look back, the faster the expansion appears.
Copeyfrom the "Alma " thread where this was well hashed out:

"The 'sphere expanding through time' model, proposes a middle ground. The movement through [time] is constant, one second at a time, and the same amount of increase in radius happened each second. That made the universe double in the first 2 seconds, but adds 0nly a 1/ 10^-36 each second now. the big increase is over, and it have happened as shown by high school level geometry"

Last edited: Jul 23, 2018
9. ### HaydenRegistered Senior Member

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Any thoughts on light emitted just at the spatial horizon of the universe (sphere).

The light propagates in all the direction, but this photon being at horizon has no space to move away outwardly?

10. ### nebel

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Hayden if you are inquiring of the universe sphere in the sketch on #5,, here is a copy/past.:
"#3 is the zero thickness membrane that is thought of to contain all matter of the universe. ( zero thickness because it's zero dwell on its movement into the future)."
This abstract sphere 3 is the locus of all the matter that moved through time since the Big beginning, the radius being the age.
There is thought to be no emission outward from that membrane, all interactions, like the detection of your object's radiation from the past, take place inside the expanding membrane and always did. It is thought though, that the effects of mass/ gravity would be felt outwardly, as the shell theorem dictates (Gravity only on the outside). That hypothesis leads to the conclusion that there must be an eternity in the future outside the universe, the time that it is moving into. After all, gravity peters out to zero only at infinity
Here is a copy from page 34. posts 675, 676 from the related "ALMA" thread " recommanding a detailed read.

a clearer picture courtesy of davec426913

, for text go to astronomy, gravity in out.

11. ### Write4UValued Senior Member

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I believe the current world population growth is estimated at 1%, which means that, if this trend continues, in 70 years the population will be 16 billion and in 140 years from now the world population will be 32 billion people.
As Bartlett observed this trend will stop. The question is how will it stop. Will we choose voluntarily or will we let nature choose for us?

12. ### nebel

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Write4U: since humans are in this neighbourhood the universe's way of knowing itself, our age, future and past, is, kind of, on topic.
The effects of the coming squeeze is already showing with chaos, resulting mass migration, legal or not, and push back to it, becoming the main themes.
just a note on the path of photons through the expanding universe. Whenever expansion was slower than the speed of light, a spiral path out of the smaller past resulted. The universe was smaller in all directions, so: spirals converging on us, the observers.

here is such an symbolic spiral going through increasing sizes, from page #30, post#596 of "Alama"

13. ### HaydenRegistered Senior Member

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Why only not inside membrane?
Is it accepted statement without proof?

14. ### nebel

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Assuming that accepted and proven physical laws apply to the universe as well as the Expanding Membrane model, (and it is only a simple model), developed in the "AMA" thread, than the accepted shell theorem, proven in more than one way* teaches that there is no gravity inside an empty shell, and therefore the past is empty, non existent. --- neither is there an electromagnetic field inside a Gauss/ Faraday cage, the electron equivalent to the (non existant)_ graviton.
The past is really a septic, lifeless, inert timespace. (Pages in the 30s on "ALMA"
* one way is to calculate the cancelling effectof the near smaller mass, and the further, greater mass, at any inside point, in a similar pattern to Kepler's perihelion, aphelion area law.

Last edited: Jul 24, 2018
15. ### NotEinsteinValued Senior Member

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You lost me there. Expansion (in this context) is a rate, like an acceleration, not a velocity, so saying "expansion at half the speed of light" is incoherent. Can you please rephrase or reformulate this statement?

16. ### HaydenRegistered Senior Member

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No, on the context, it is not incoherent.

17. ### Q-reeusValued Senior Member

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Hadn't noticed that same error back in #7, #33, #34, (belated qualifier by one poster in #56)? I was tempted to jump in back there in #7 but from experience, it only keeps repeating. Given even 'reputable' sites make that same 'expansion faster than light' statement, the confusion will likely never disappear.

18. ### NotEinsteinValued Senior Member

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Can you please still explain what you meant, because I don't understand what "expansion at half the speed of light" means here.

Phrasing such as "expansion faster than light" can be coherent if one is explicitly talking about the expansion of a specific distance between two objects (notice that if one fills in the distance D in Hubble's Law, it'll give a velocity back). But when talking about the universal expansion in general, it's bad phrasing to the point of incoherency. At the very least it's unclear what is meant if this velocity is treated as some equivalent of the expansion rate without specifying the distance D.

19. ### NotEinsteinValued Senior Member

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Oh, I see Hayden has been banned. Never mind then, I guess.

20. ### Q-reeusValued Senior Member

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Yeah I was lazy in not explicitly stating 'expansion rate faster than light' as apocryphal meme. Heyden was a sock? Of which previous incarnation I wonder?

21. ### NotEinsteinValued Senior Member

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I've learned that most good physicists are lazy in that way.

It was suggested in this thread that Hayden might have been RajeshTrivedi, but you'd have to ask James R for confirmation.

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