Do we know how big it is? Or old? do they keep making it older?

Of course it's getting older. It's not getting any younger, and time is passing .

Our cosmological models are (I think) all fucked up, haha. Our best guess (from the redshift) is that the universe is expanding. The interesting thing about this is that if the universe expands, then the concept of time is literally changing too. All things are measured by the speed of light... so, for instance, suppose you have two points a meter away from each other... but within 1 second, space is expanding so fast that that 1 meter will become 2 meters, at a constant expansion rate. Then suppose that the first point emits light once every half-second (in its time). The speed of light is constant... so the first light pulse will need to travel 1 meter + [however much more space "grows" during it's travel time]. The second light pulse will need to travel 1.5 meters + [however much space "grows" during it's travel time]. So while the first point says "I'm sending off pulses of light once every .5 seconds," the second point says "I'm receiving light pulses once every .5000000001 seconds."

Although... scientists can't actually pinpoint the "center" of the universe. All they can tell is that everything is getting farther away from everything else.... sort of like raisins in a loaf of rising bread. This basically means that everyone in the universe (if there were people on other planets in other galaxies, that is) will think that everyone else has existed for longer than that person measures themselves as existing.

It's a fascinating question... how old the universe is. It really seems to depend on which point of view you want

Amazing. Thank you Cryptonia.

I wonder if they are teaching this stuff in schools, that the universe is not static etc.

hm... I'm not sure. I know I never heard of it 'til I went to college (am a physics major), and even then, I only heard about it from the "colloquium". er... basically a seminar where professors give 1-4 lecture series' on way upper-level physics, to give you a taste of them and help you decide what branch you want to move into for grad school.

I'd bet a lot of your Ne types who are into science or cosmology hit some point where they just go "I wanna learn about this!" and read the basics on their own, though.

There's a whole heck of a lot of misunderstandings about science and some of the things that it finds that everybody who's not studying it seems to have, though, and school doesn't even attempt to address them... so I doubt this one's talked about much, either.

I wonder about most things they teach in school. Like for instance, in the beginning of one of my textbooks it defines evolution as a theory, and in the end of the book it says it's not a theory, it's a fact.

Science is in it's infancy, there's not a whole lot of things that we "know" aside from that we're currently alive. Medicine is really scary when you get down to it. It's really guesswork and imperfect. If doctors can't perfect interacting with/fixing the human body, or that of animals, I don't have much faith in their familiars telling me much about the universe with any sort of accuracy.

I'm a natural born sceptic, I question things that are presented as facts, especially things like the origins of life and the nature of the things around us, since they seem to change every so often. I mean, it wasn't really that long ago that someone would be scoffed at for saying the earth was round. I don't think it's something we can really know at this point in time. We haven't really gotten to the bottom of much.

Posted By cryptonia on 24 Jul 2009 09:56 AM
Of course it's getting older. It's not getting any younger, and time is passing .

Our cosmological models are (I think) all fucked up, haha. Our best guess (from the redshift) is that the universe is expanding. The interesting thing about this is that if the universe expands, then the concept of time is literally changing too. All things are measured by the speed of light... so, for instance, suppose you have two points a meter away from each other... but within 1 second, space is expanding so fast that that 1 meter will become 2 meters, at a constant expansion rate. Then suppose that the first point emits light once every half-second (in its time). The speed of light is constant... so the first light pulse will need to travel 1 meter + [however much more space "grows" during it's travel time]. The second light pulse will need to travel 1.5 meters + [however much space "grows" during it's travel time]. So while the first point says "I'm sending off pulses of light once every .5 seconds," the second point says "I'm receiving light pulses once every .5000000001 seconds."

Neat! It's like the space-time doppler affect! "vroooooooooooooooooooooom"

 

Posted By coralaisly on 14 Nov 2009 08:34 PM
I wonder about most things they teach in school. Like for instance, in the beginning of one of my textbooks it defines evolution as a theory, and in the end of the book it says it's not a theory, it's a fact.

Evolution is a weird one.  Well, not really.  A lot of science is like that... it's weirdness is just exposed because of all the religious-politics surrounding it.  I would compare what evolution is like to.... well, suppose we had a telescope out, focused on some atmosphere-less planet, and watched a comet graze against the surface and knock a chunk of dirt from the planet loose, and both the comet and dirt had enough energy to escape the planet's gravitational field.  Suppose we see this happen every century or so, and the planet shrinks a bit each time a comet grazes against its surface.  You would suspect that, given enough time, there would eventually be no planet there.  You see pieces of hit getting chipped away over time, and nothing makes it grow, so you make a theory that planets can be destroyed by comets grazing against the surface.

Now, you've never really seen a planet be destroyed by grazing off the surface.  You've only seen pieces of the planet being chipped away.  However, you have 0 reason not to think that the planet you're observing won't be destroyed someday.

 

This is roughly the same as evolution.  We have seen entire populations of animals change traits before.  Populations of deer that were once brown, in snowy regions, have become white over time, simply because one deer was born albino, the white fur helped it blend in/not get eaten, it had albino offspring, and their fur helped them blend in/not get eaten, etc.  Over time, you went from all brown deer to mostly-white deer, with a few brown-deer surviving still.  If this is what you call evolution, then it's observed fact.  The claim is that given this observable fact, we create a theory that says "everything we see could have come into existence like this."  You start out with brown deer, and they become white.  Then the muscle fibers of a deer are formed differently from proteins, and those turn out to be stronger than the original, so soon the deer pick up a different type of muslces.  Then they migrate down south a bit, where it's warmer, and one deer loses its fur, helping it keep cool.  Now is this extra-muscly, no-fur, deer-like creature the same species as the one up north?  Scientists draw those boundaries based on whether or not they can produce offspring which can produce... but all that really is is a title.  Many small meteors chipping away at the planet leave no planet behind, and many small mutations in a population of animal eventually create a new species.  "Fact" is terrible word like 99% of the time... but I suspect they wanted to make it clear that they're not making the claim that anything different than what we have observed happens in evolution.  They're instead claiming that what we observe has happened many times in the past.

Also, evolution has absolutely nothing to do with the origins of life.  That would be abiogenesis, a different story altogether.

 

The Physicists at my college do joke about how primative we are sometimes, though.  "What's in the coconut?"  "*grunts* I dunno... go grab rock?  Smash coconut with rock: see what's inside."  "What's in this proton?"  "hmm... let's get a pair of em going *really* fast, and bash them into each other!  At least, it's worked in the past..."