Age of the universe

[Smalso]

http://www.reuters.com/newsArticle.jhtml?type=scienceNews&storyID=2211154

Man, oh ,man! Is this big news, or what?

[hammegk]

One of the cable news channels put the picture up, mentioned the 13.7 b yrs, but also made the comment "this study concluded the universe is flat". Seems a bit hard to believe they solved that problem too.

Certainly nothing like that in the article posted.

[garys_2k]

They mentioned this on National Public Radio this morning and gave these conclusions drawn from that probe's study:

- The universe is 13.7 b years old, +/- 2%
- The universe will never stop expanding, there is not enough matter/energy for a big crunch
- About 1/4 of the universe is made up of ordinary mass and energy, about 35% of dark matter, the rest "dark energy"

They said that that last bit is some sort of anti-gravitational energy that seems to pervade space. Very wierd, but cool nonetheless.

----
- The universe is 13.7 b years old, +/- 2%
----


According to our primative dating methods.

It is actually much older I'd guess.


----
- About 1/4 of the universe is made up of ordinary mass and energy, about 35% of dark matter, the rest "dark energy"
----


Ahh, the magical explanation for why theory doesn't match obsevation.

[rwald]

Originally posted by Whodini
Ahh, the magical explanation for why theory doesn't match obsevation. You prefer, "It was God's will, and God can do whatever He wants"?

[Oso]

Must be hell for the Young Earthers.
Here's a couple more links.

http://antwrp.gsfc.nasa.gov/apod/ap030212.html

http://www.nasa.gov/HP_FLB_Feature_MAP_030211.html

and
http://www.newscientist.com/news/news.jsp?id=ns99993375
20:00 11 February 03
NewScientist.com news service
...
MAP is the successor to NASA's Cosmic Microwave Background Explorer (COBE), which recorded the relic radiation across the whole sky for the first time in 1992. Crucially, COBE revealed tiny temperature differences that reflect early variations in the density of matter, the seeds of galaxies.

Since then, teams of astronomers have mounted an army of ever more sophisticated detectors on mountaintops and on balloons to measure these ripples with ever increasing detail. These findings have revealed that the Universe is "flat" and confirmed that the Universe is expanding at an ever faster rate.

[rwald]

Originally posted by Oso
These findings have revealed that the Universe is "flat" and confirmed that the Universe is expanding at an ever faster rate. Wasn't that a contradiction? I thought that hyperbolic universes expanded at an ever-increasing rate, and flat universes expanded at an ever-decreasing rate...

Am I just confused?

[Oso]

Originally posted by rwald
Wasn't that a contradiction? I thought that hyperbolic universes expanded at an ever-increasing rate, and flat universes expanded at an ever-decreasing rate...

Am I just confused?

Here's a better link. This was over 2 years before the recent confirmation. Don't you just love science.

http://physicsweb.org/article/world/13/6/3/1

[rwald]

OK, universe flat, got it. But why does that lead to a ever-accelerating expansion? I would think that in a flat universe, the expansion rate should decrease and approach 0 asymtotically. Am I mistaken about this? It's possible; I just want to know what the truth is.

[Oso]

The link I gave above is probably about as good a discussion of this that you'll find. You're right it's confusing, and it ain't easy.

Start reading one paragraph above the heading precision measurements.

[rwald]

I've heard of inflationary theory, but never really understood it. Does that mean the the universe's geometry and fate are not correlated?

Originally posted by rwald
You prefer, "It was God's will, and God can do whatever He wants"?


Uh, no.

Because I disagree with a scientific explanation doesn't mean I endorse a religious "explanation".

[rwald]

Just checking.

So, what do you think does explain for the fact that the density of the universe appears too low? Maybe not dark energy per se, but there's definitely something we're not seeing.

[RichardR]

Originally posted by Whodini
"dark energy"
----


Ahh, the magical explanation for why theory doesn't match obsevation. [/B]What would you do when the observation contradicts the theory?

Dark energy/matter is a working hypothesis. It may well be superceded when more is learned in the future, but that is the way with all of science.

[The Bad Astronomer]

It has been taught for a long time that a flat Universe decelerates so that when time goes to infinity, the expansion stops. That is only true if there is no cosmological constant; that is, all you have is a Universe filled with matter and therefore gravity.

In 1998, it was determined that the expansion of the Universe is accelerating. This changed everything, including the idea that the geometry of the Universe is all that determines its fate. Now it's understood that geometry is only a part of the problem.

No one knows what is causing the acceleration. It acts like an energy in space itself, but undetectable (so far). That's why it's called "dark energy". It's just a name to hang on the idea until we figure out more.

[Elektrix]

OK, I tried reading through that PhysicsWeb article, but I'm still a little confused by the notion of the Universe being "flat"......what exactly does that mean........that the universe is sort of like a gigantic disc (i.e. as opposed to a gigantic sphere or just a bunch fo space heading out in all directions).

As a general point, if it is "flat", what is there outside of the universe? Or is that the same as asking what was around before the big bang. Maybe I'm also confused about what the universe itself is, and then what we would refer to anything that is outside the universe (as this seems to imply the universe is finite, rather than infinite).

Sorry, I just don't know much about this, and it hurts my head thinking about it....:)

-Elektrix

[Oso]

Originally posted by Elektrix
...I'm still a little confused by the notion of the Universe being "flat"...

...(as this seems to imply the universe is finite, rather than infinite).

...it hurts my head thinking about it....:)
Flat is one of those common words that gets used but unfortunately brings along baggage (Vacuum is the one that burns me the worst, it comes with a lot of baggage). Flat doesn't mean the universe only has 2 dimensions. Briefly stated it means 2 parallel lines stay parallel, they neither converge nor diverge. This actually should imply the universe is infinite but that is still very much up for debate.

Here's another link that does a pretty good job presenting the debate.

http://sci.esa.int/content/doc/00/30208_.htm

It hurts your head thinking about it? Don't worry you're not alone.

It's a very bizarre world and I'm a happy guy.

[Smalso]

Those great pictures from the Hubbel of all those tiny points of light, each one of them a galaxy containing hundreds of billions of stars, and that picture only a small part of the universe. If each of those galaxies had only one Earth-like planet and only one of a millin of those planets had life, the universe would be fairly teeming with life. THAT makes my head hurt.

Originally posted by Smalso
Those great pictures from the Hubbel of all those tiny points of light, each one of them a galaxy containing hundreds of billions of stars, and that picture only a small part of the universe. If each of those galaxies had only one Earth-like planet and only one of a millin of those planets had life, the universe would be fairly teeming with life. THAT makes my head hurt.


Yeah, god did a good job.

[Skeptical Greg]

Originally posted by Whodini



Yeah, god did a good job.


Where he bothered...

But then again, maybe retardation is God's idea of a joke..

[Bobo]

Originally posted by RichardR
Dark energy/matter is a working hypothesis. It may well be superceded when more is learned in the future, but that is the way with all of science.

And THAT is why science rocks so hard.

Science is progressive and cumulative and only improves by being challenged, dogmatic mythology only buckles under the same scrutiny.

Bobo

Originally posted by Diogenes

Where he bothered...
But then again, maybe retardation is God's idea of a joke..


Could be.

Or a god could have created everything, then evolution took over.

Or maybe retardation is only 'bad' from a human-centered point of view?

[Smalso]

Or a god could have created everything, then evolution took over

Or we could just skip a step and acknowledge that it exists however it come to be. The Theory of Evolution--at least my understanding of it--works very well without the god hypothesis.

[DrMatt]

Originally posted by Diogenes



Where he bothered...

But then again, maybe retardation is God's idea of a joke..

Anyhow, even if all those galaxies WERE to contain a planet harboring intellegient life, the chances of us ever meeting any of them is pretty slim. Personally, I suspect that intelligent life happens much more often than once-per-galaxy, and encounters between separately-evolved sentient races probably happens almost zero times.

[Smalso]

Originally posted by DrMatt


Anyhow, even if all those galaxies WERE to contain a planet harboring intellegient life, the chances of us ever meeting any of them is pretty slim. Personally, I suspect that intelligent life happens much more often than once-per-galaxy, and encounters between separately-evolved sentient races probably happens almost zero times.

Good point and one I have thought about many times. Even if life happened a million times per galaxy, the chance of contact between any two of them is very small.