age of the universe
Feb. 9th, 2010 02:02 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
miriam_eI was just reading a piece discussing the expansion of the universe. The writer was extrapolating backwards to find an estimate of how old the universe is, but the particular passage was written before evidence was found that the expansion looks to be accelerating.
As most readers of my ramblings will know, I'm not fond of the idea that the universe started in a Big Bang. I'm not saying it definitely didn't happen, just that I find it very unconvincing. I've often stated my reservations this way:
I know a lot of people have problems with infinity, but if the universe is infinite in size (something I "prefer" because I find it easier to imagine) then the universe could have been expanding forever but always been infinitely big... just becoming a larger infinity. :) (That pop you just heard was your mind breaking.) Or it could have "bounced" long before reaching the zero point, having previously collapsed to some density limit.
And yes, I know there is other observational data like the makeup of galaxies as we peer back in time with our telescopes, but none of that says conclusively that there was a big bang. It could be that there was a local catastrophic event, or that galactic births follow cycles. We don't really know.
I don't count the cosmic microwave background radiation as "proof" of the big bang. I remember when I was a kid reading science journals the microwave background was at one point considered evidence against a big bang.
My point is not to say what did happen, but to point out that believing there was a big bang seems a mistake. Such belief is based on inferences that always looked to me less than convincing at best, and "magical" thinking at worst. It seems to me that it jumps to conclusions, when there may be other ways of looking at the data.
Just to reinforce my point: I'm not saying a big bang did not happen. I'm just saying I find it hard to swallow, and so long as I can come up with alternatives I'm not going to believe any single explanation... even ones that feel right to me. I reserve judgment. I certainly won't believe something just because others do.
As most readers of my ramblings will know, I'm not fond of the idea that the universe started in a Big Bang. I'm not saying it definitely didn't happen, just that I find it very unconvincing. I've often stated my reservations this way:
"Europe is the center of the universe"Well, I was thinking... assuming the expansion is real and not an error in our deductions, and what we can see of the universe really is expanding non-linearly then it is conceivable that there never was a time when it was a single point-source. If the graph of size against time is a curve that becomes less and less steep further and further in the past then who is to say it ever intersects the zero-size mark on the graph? It could approach forever, asymptotically, some size, not necessarily even a small size.
"Oops. The Earth is a sphere, not flat."
"Well, Earth is the center of the universe."
"Oops. We travel around the sun."
"Oh. Well, The sun is the center of the universe."
"Uh, see those stars in the night sky? They are suns... and ours is a pretty ordinary one."
"Well we are in a big thing called the Milky way; the only one."
"Wrong again. Lots of those things that look like stars are galaxies containing billions of stars each."
"Well, it all expanded from one single thing at a certain time in the past."
"Ummmm..."
I know a lot of people have problems with infinity, but if the universe is infinite in size (something I "prefer" because I find it easier to imagine) then the universe could have been expanding forever but always been infinitely big... just becoming a larger infinity. :) (That pop you just heard was your mind breaking.) Or it could have "bounced" long before reaching the zero point, having previously collapsed to some density limit.
And yes, I know there is other observational data like the makeup of galaxies as we peer back in time with our telescopes, but none of that says conclusively that there was a big bang. It could be that there was a local catastrophic event, or that galactic births follow cycles. We don't really know.
I don't count the cosmic microwave background radiation as "proof" of the big bang. I remember when I was a kid reading science journals the microwave background was at one point considered evidence against a big bang.
My point is not to say what did happen, but to point out that believing there was a big bang seems a mistake. Such belief is based on inferences that always looked to me less than convincing at best, and "magical" thinking at worst. It seems to me that it jumps to conclusions, when there may be other ways of looking at the data.
Just to reinforce my point: I'm not saying a big bang did not happen. I'm just saying I find it hard to swallow, and so long as I can come up with alternatives I'm not going to believe any single explanation... even ones that feel right to me. I reserve judgment. I certainly won't believe something just because others do.
![[identity profile]](https://www.dreamwidth.org/img/silk/identity/openid.png){kind=small}
no subject
Date: 2010-02-09 04:07 am (UTC)That makes a strange kind of stoned logic.
no subject
Date: 2010-02-09 04:45 am (UTC)There is an infinity of infinities.
If you like to play with infinities, think of the Mandelbrot set. The mandelbrot set is a fractal object, a definite geometric object, which fits inside a square less than 4 units by 4 units (I can't remember the actual limit, but it is smaller than 4). The figure is actually a mapping of a boundary between values inside and outside complicated fractal curve... a curve which is infinite in length. How can something infinitely long fit inside a finite area? Because the curve meanders around on ever smaller scales, each bend making it longer. Infinite numbers of bends and wiggles make it infinitely long.
Fun huh?
I l♥ve this stuff.
no subject
Date: 2010-02-09 04:47 am (UTC)Wouldn't that just be an infinity?
I play in infinity not with infinity. :)
(My head hurts now)
no subject
Date: 2010-02-09 08:47 am (UTC)Well thank you, that doesn't happen very often. :)
Anyhoo, makes sense to me.
I'm sure I haven't researched it the way you have but the thinking seems good.
I've always thought well maybe a big bang but so far it seemed a stretch to call it *the* big bang.
Your words reminded me of my junior high science class wherein our teacher took a single class period to explain a few origin of the universe theories. I think it was big bang/evolution, creation, and a combo of the two. I know, we didn't explore it very deeply.
But it got me thinking, I started trying to imagine infinity, or imagine what before the big bang, and especially I started to wonder why anything at all, rather than eternal nothing. My mind was a knot of wonder for a bit there. That there is anything at all seems like the most beautiful miracle.
:)
Anyhoo, thank you.
no subject
Date: 2010-02-13 11:23 pm (UTC)On the point of why there is anything at all, it may be less surprising that it seems. There are theories that there may be countless universes, some essentially empty. The idea is that most will have different fundamental settings that cause the forces of nature to operate differently. In those life will most likely not arise. Only in this one and some tiny fraction of all the universes (though even that fraction might still be an infinite number) will there be life. When we look around we marvel at a world that produced us... because we couldn't have developed in any of the others.
What I like about that possibility is that it would explain so much, while making the world even more wonderful. I get a cozy feeling from it, like snuggling up in bed when a big storm rages outside. :) Of course my delight for it doesn't make it true; there may well be other, even cooler explanations. I hope I live to see more. Living and learning are grand!
no subject
Date: 2010-02-14 07:43 am (UTC)Or yes, as you say both ways. I tend toward thinking AND is the most likely thing. So though I hadn't heard these theories before, it sits real comfortably with me too. Thank you. I like that coziness. :)
It's a wonder that we are at all. It's pretty fancy that. :)
Cardinality
Date: 2010-02-10 10:58 pm (UTC)I've recently finished reading ""The Science of Discworld III: Darwin's Watch" by Terry Pratchett, Ian Stewart & Jack Cohen.
It alternates chapters of a fantasy novella with chapters on real science, history & philosophy.
Chapter 14 Aleph-Umptyplex is about the concept of infinity.
It introduced me to the ideas of Georg Cantor - a brilliant 19th century mathematician who pondered the very fundamentals of mathematics.
Cantor went all the way back to the concept of counting - 1,2, 3, etc.
He asked how many elements are there in the set of whole numbers? This is the 'cardinality' of the set.
We'd be tempted to say "infinity" but Cantor called it Aleph-Zero. (Aleph being the first letter of the Hebrew alphabet.)
The cardinality of the set of whole numbers is Aleph-Zero.
Then he considered the set of *all* infinitely long decimal numbers - of which Pi is one.
The cardinality of this set turned out to be 10 to the power of Aleph-Zero!
Cantor had invented the concept of transfinite numbers - and had shown that some "infinities are bigger than others!"
The Discworld chapter explains the concepts very well - the Wikipedia article is more obstruse: http://en.wikipedia.org/wiki/Aleph_number
Cheers!
MFG.
Re: Cardinality
Date: 2010-02-13 11:41 pm (UTC)Science fiction performs a such important role. I first came into contact with Cantor's transfinite numbers through a three-part serial in Worlds of IF magazine back in August 1967. It was called "Faust Aleph Null", and written by James Blish. My memory is so bad I can't remember what the story was about, but I still have the issue and will dig it out later to re-read. All I remember is the name of the story, so used my catalogs to search for it. Even though the story quickly faded from memory it caused me to learn more about infinities. As I say, science fiction performs a wonderful service by attracting people into this stuff and prompting them to fill their newly expanded minds with cool knowledge.