Question for astronomers

[Houngan]

A person has recently challenged my assertion that the universe, according to conventional wisdom, is ~14.5 billion years old. Could someone please tell me I'm not crazy, and that my memory is still working?

H.

 

[Denise]

http://www.astro.ucla.edu/~wright/age.html

I know not much about this subject. But I found a link for you. I think you should pm the bad astronomer or go to his website as he is schooled in the discipline. Tell him I asked you to pm him if you feel better. He's very nice and likes to help.

 

[Patricio Elicer]

I'm not an astronomer, but I know that the conventional wisdom is that the universe is between 15 and 20 billion years old. That is between 15,000,000,000 and 20,000,000,000 years old

 

[ahirst]

The thing about astronomy is that much of it is guesswork - albeit highly educated guesswork. This is because it is generally very difficult to do laboratory experiments on the scale required. And, with the exception of some particle physics and the odd space probe and lunar or Mars lander it is also difficult to 'go there and find out' or measure it.

Therefore most astronomy relies on observation and analysis of the various electromagnetic radiation waves and particles which are received at the Earth's surface, or satellites and high flying balloons and aircraft, as the case may be. Some of this can be extremely accurate, but much relies heavily on comparisons between similar data.

Hence when I studied astronomy (some 10-ish years ago) a general rule was that many astronomical measures and calculations were acceptable if they had an uncertainty of less than about a FACTOR of 10 (ten), i.e. if it was somewhere in the range of about a tenth to 10 times what it might be.

Distances and ages for stars and galaxies are particularly tricky to ascertain as they rely on comparisons between star brightness plus spectrum, and what is basically an empirically derived sequence of stellar evolution.

An example of this for distance is that the diameter of our own galaxy (Milky Way) is not exactly known, the best estimates I know of place it between 20 and 40 kpc in diameter. This is mainly due to line-of-sight issues, i.e. we can't really see through to the centre of the galaxy because of all the stuff (a highly technical term) in the way, together with dark matter issues.

So if you take a figure of 15,000,000,000 years old as meaning something in the region of, say, 10,000,000,000 to 30,000,000,000 years old, it sounds reasonably accurate.



Hope this is of some use. Cheers.

 

[Crossbow]

The universe is:

13.7 Billion Years Old!

(give or take 1%)

Results from a recent study done by NASA on this subject and the details are at:

http://map.gsfc.nasa.gov/m_mm/mr_age.html

 

[ahirst]

An excellent site Xbow.

However I was slightly involved with some analysis of the COBE data mentioned, and although the accuracy of the WMAP data is undoubtedly much better, I am still a bit sceptical about the 1% accuracy given for the age of the universe.

Some of the 'broad brush' details on the site contain more than a few 'if...should' s and at least one 'theoretical models predict'. I know how its tempting to follow a theoretical construct, but feel that the further away it gets from its 'anchors in reality' the more tenuous it becomes. For instance I haven't (as yet) encountered a convincing treatment of what must have been large relativistic time distortion effects for particles shortly after the 'big bang' (always assuming this model of the beginning of the universe is correct).

I'm not sure about 'Inflation' but I would have though certainly that the 'Variable Speed of Light' theory could play havoc with predictions of the age of the universe.

Anyway, time will tell.

Cheers.

 

[Andonyx]

Out of curiosity, what was your friend's objection to that estimate of the age of the universe?

 

[Houngan]

HIS memory told him that it was 12 billion, and I knew that figure was out of date. Unfortunately, the 13.7 drags it closer to his figure than I like.

H.

 

[Guest]

Dear all,

I predict, in all of my non-astronomer wisdom, that the estimate will curiously keep getting larger and larger and ...

Sincerely,

S. H.

 

[Houngan]

Dear all,

I predict, in all of my non-astronomer wisdom, that the estimate will curiously keep getting larger and larger and ...

Sincerely,

S. H.

If the 13.7 is correct, then it is actually a step backwards.

H.

 

[Dancing David]

There was some excitement when they found a star that was 14 billion (american) and the given age was less than that, then they upped the age.

Peace

 

[rwguinn]

There was some excitement when they found a star that was 14 billion (american) and the given age was less than that, then they upped the age.

Peace

I gotta ask- Are American years longer than European years-or does it just seem that way??

Roger

 

[Captain Trips]

No, an American billion is a European "thousand-million." What Europeans call a billion is an American "Trillion."

At least, that's what I learned in high school German class. (Ein Million = One Million. Ein Millionen = One Billion. Ein Billionen = One Trillion.)

 

[UnrepentantSinner]

No, an American billion is a European "thousand-million." What Europeans call a billion is an American "Trillion."

At least, that's what I learned in high school German class. (Ein Million = One Million. Ein Millionen = One Billion. Ein Billionen = One Trillion.)

I learned the word "Millarde" to mean billion.

But we're both correct.

http://dict.leo.org/?search=billion...tHdr=on&tableBorder=1&cmpType=relaxed&lang=en

 

[Dancing David]

Given the american lifestyle maybe years would be shorter because we move faster.

Peace

 

[rwguinn]

No, an American billion is a European "thousand-million." What Europeans call a billion is an American "Trillion."

At least, that's what I learned in high school German class. (Ein Million = One Million. Ein Millionen = One Billion. Ein Billionen = One Trillion.)

Let's here it for scientific notation! just say 10**9 (10^9 for you children) and EVERYBODY knows wht you're talking about...

 

[LucyR]

I hate to tell you but that's not scientific notation. Looks more like FORTRAN or some other code.

 

[rwguinn]

I hate to tell you but that's not scientific notation. Looks more like FORTRAN or some other code.

Sorry- but my superscripting won't work on this forum.

Is that what scepticism is to you folk? criticizing the other guy's language, since you can't fault his thinking? Everyone who deals with numbers knows the "double star" or the "hat" denote a superscript, i.e., the preceeding number raised to the trailing value. If you prefer, we can also say 10E+09. Take your choice. But don't criticize unless you have established a convention, and made everyone aware of it.


Roger

 

[aerocontrols]

I gotta ask- Are American years longer than European years-or does it just seem that way??

Roger

Stupid metric time is always messing up my calculations.

 

[Soapy Sam]

It's rampant deflation. When I was a kid, a billion was 10^12
Nowadays, most Brits have fallen into the American 10^9 usage.
I feel I've been short changed somehow.