Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
Happy birthday, Universe!
Kinda. It’s not really the Universe’s birthday, but now we do know to high accuracy just how old it is.
How?
NASA’s WMAP is the Wilkinson Microwave Anisotropy Probe...
Location: Los Angeles, which as I understand was once upon a time ago part of the United States of America
849 posts, read 1,046,839 times
Reputation: 314
This is big news, but I've only just heard about it on Phil's blog. I guess the typical American would rather discuss Clinton/Obama or Britney Spears. Anywho, this is the most interesting:
Quote:
4) The Universe is flat.
Meaning it's 3-dimensional but has edges, so you get to the end of the universe and there's a boundary of sorts, and the shortest distance from one point to another is still a straight line, meaning there are no warps in 3-dimensions of travel.
Quote:
5) The energy budget of the Universe is the total amount of energy and matter in the whole cosmos added up. Together with some other observations, WMAP has been able to determine just how much of that budget is occupied by dark energy, dark matter, and normal matter. What they got was: the Universe is 72.1% dark energy, 23.3% dark matter, and 4.62% normal matter. You read that right: everything you can see, taste, hear, touch, just sense in any way… is less than 5% of the whole Universe.
More remarkable information. Now we know that most matter is dark -- meaning it's invisible and hence light passes right through it.
IIRC, the only evidence of dark matter is that there are unexplained gravity effects where there is no matter or apparent black holes. FWIW, there also is a force that is actually accelerating the expansion of the universe. (Perhaps an attraction to emptiness?) All of this could be neatly explained if the eleven or so dimensions proposed in string theory were thought to have effects when they impinge on the normal four dimensions, but AFAIK, current thought is that the dimensions (loosely explained) curl up on themselves and are very small.
There is a philosophical/science component to all this. If we are only affected by the four dimensions, then the laws of physics must hold absolutely, which then dictate that every action, reaction, thought in man, and all future actions to the end of the universe were pre-ordained at the beginning of the universe. In other words, there is no free will and as much as we think we are modifying our environment, we aren't and can't. Each attempt to change it was still pre-ordained, since the pattern of molecules in our brains, the energy levels of our environment, and everything that goes into that thought process was pre-ordained. Philosophers have simply not been able to come up with a mechanism to dispute this, even on nano-scales.
Computer programmers and cryptographers run into a somewhat similar problem when they attempt to create truly random number. If you fight to get a random number, you eventually conclude that "random," as normally used, is a word that only means the system or event seems too complex to understand, but that the "random" can be traced back to a finite "seed" that has been manipulated.
I happen to think that the other dimensions are more complex than the physicists believe, and that there is some mechanism where one or more of them interact with the brain. For instance, the attraction to emptiness would explain the fascination some people have with Brittany Spears.
I happen to think that the other dimensions are more complex than the physicists believe, and that there is some mechanism where one or more of them interact with the brain. For instance, the attraction to emptiness would explain the fascination some people have with Brittany Spears.
I still don't get it. Even a sheet of paper has 3 dimensions (the edge has some depth). If the universe began as a single point it must have expanded equally in at least 3 dimensions, no?
"The Universe itself expanded outward from a single point — actually, it’s space itself that expands, not the objects in it "
So what does space expand into? There must be some milieus, some context in which it is suspended and expands into. And if it was infinite it wouldn't be expanding so there has to be a limit, a boundary to space. If there wasn't it couldn't expand since the definition of expansion is the moving outward of boundaries. This is all so mind boggling and improbable. The universe really shouldn't exist. It's impossible!
If you left earth, say "north" or "south" from the plane of the earth's movement around the sun, and kept going at the speed of light, you would never reach the "edge," according to what I've read. For one thing the universe is expanding and for another, your path would curve. There was the old joke, probably told by Einstein, that if you had a strong enough telescope, you could [eventually] see the back of your head.
If you left earth, say "north" or "south" from the plane of the earth's movement around the sun, and kept going at the speed of light, you would never reach the "edge," according to what I've read. For one thing the universe is expanding and for another, your path would curve. There was the old joke, probably told by Einstein, that if you had a strong enough telescope, you could [eventually] see the back of your head.
I'll believe the number when it stays consistent for longer than 5 years. I think we're at a very interesting time in cosmology and we are continuing to learn so much that to say the 13.73 number is absolutely correct is premature.
Quote:
Originally Posted by geos
4) The Universe is flat.
I still don't get it. Even a sheet of paper has 3 dimensions (the edge has some depth). If the universe began as a single point it must have expanded equally in at least 3 dimensions, no?
"The Universe itself expanded outward from a single point — actually, it’s space itself that expands, not the objects in it "
So what does space expand into? There must be some milieus, some context in which it is suspended and expands into. And if it was infinite it wouldn't be expanding so there has to be a limit, a boundary to space. If there wasn't it couldn't expand since the definition of expansion is the moving outward of boundaries. This is all so mind boggling and improbable. The universe really shouldn't exist. It's impossible!
It's completely counterintuitive, but something can be finite and not have any edges. An incomplete analogy would be the surface of the Earth--it is clearly finite but doesn't really have any edge. The analogy is incomplete because the Earth is embedded in the third dimension whereas the universe is four dimensional (counting time) and does not necessarily have to be embedded in a higher-dimensional space. That non-Euclidean geometries don't have to be embedded in higher-dimensional spaces is equally counterintuitive.
Conceptualizing non-Euclidean geometry and higher-dimensional geometry is very difficult for people, because our brains have evolved in a locally Euclidean, three-dimensional world. Like quantum mechanics, some of the predictions of general relativity are completely at odds with everyday experience so, when thought of using common sense and physical intuition, lead to seemingly paradoxical results. There is no paradox, of course, because its not general relativity that's wrong, only that your intuition doesn't apply to the scales that general relativity is trying to explain.
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.
Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
