Questions about the universe

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Grammatolatry
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Questions about the universe

Post by Grammatolatry »

You guys are smarty-pants and usually have an answer for everything, so I was wondering if you could explain this to me.

Scientists pointed the Hubble at a patch of space for 100 odd hours and discovered light from galaxies from when they were created 350 million years after the theorised date of the Big Bang http://www.nasa.gov/mission_pages/hubbl ... ensus.html
I'm wondering why in the 'explosion' of the Big Bang not all matter was pushed out to the same area? Why is there matter closer to the epicentre of the explosion, while we're out here? What held that matter closer to the centre so it could form galaxies? (What I'm asking may need clarifying, because it makes sense in my head, but I'm not sure if it makes sense here).

My second question is: if we're trying to develop of Theory of Everything that presumably contains an allowance for Time, how can that explain everything in the universe when we only know time as our earth revolving around our sun? What's to say that time isn't different elsewhere in the universe?

:/
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Re: Questions about the universe

Post by bobby 55 »

Wow! Interesting questions.

If I'm thinking correctly then the earth revolving around the the sun is just a way to get the measurement of a unit of time and not a measurement of time itself. Someone a whole lot more qualified than me might answer that question more comprehensively. :)

If I remember my science lessons when the initial explosion occurred there was just heat/energy. It wasn't until that cooled a bit that matter was formed. So I guess even though we have an expanding universe there would be matter formed at the epicentre because it formed from the stuff being cooled there. The matter wouldn't have acted like it was shot from a canon is what I'm trying to get at.
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Re: Questions about the universe

Post by G-Flex »

Grammatolatry wrote:Scientists pointed the Hubble at a patch of space for 100 odd hours and discovered light from galaxies from when they were created 350 million years after the theorised date of the Big Bang http://www.nasa.gov/mission_pages/hubbl ... ensus.html
I'm wondering why in the 'explosion' of the Big Bang not all matter was pushed out to the same area? Why is there matter closer to the epicentre of the explosion, while we're out here? What held that matter closer to the centre so it could form galaxies? (What I'm asking may need clarifying, because it makes sense in my head, but I'm not sure if it makes sense here).
There is no "center of the explosion". See: http://en.wikipedia.org/wiki/Big_Bang#H ... n_of_space

As far as anybody can tell (and there's plenty of theory and data to back this up), space is uniformly expanding everywhere. We're not at the center, and nothing else is either.
My second question is: if we're trying to develop of Theory of Everything that presumably contains an allowance for Time, how can that explain everything in the universe when we only know time as our earth revolving around our sun? What's to say that time isn't different elsewhere in the universe?

:/
The cosmological principle. Until shown otherwise, the safest and best assumption to make is that the laws of the universe hold in a general sense, not just for us. Also, what you say isn't exactly true; we've also observed things from the moon, from Mars, from elsewhere in space (to a small degree), and from various places along various trajectories in Earth's orbit, and we're generally scientifically and technologically sophisticated enough to determine differences in how things behave based on those differences in position and velocity.
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Re: Questions about the universe

Post by Jonas »

This seems like a DDL sort of question, but: time is in fact different elsewhere in the universe, in the sense that when two events happen so far apart that it would take years for the light from one event to reach the light from the other event, the concept of simultaneity no longer really applies. Bob's answer was good too though, this is just another way to look at it. I think what theoretical physicists are trying to get a handle on is how time behaves and affects objects under different circumstances (at different speeds, mostly). For example the old Einstein relativity thing with a person aging more slowly compared to another person if the first person is travelling at speeds near the speed of light.
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Jaedar
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Re: Questions about the universe

Post by Jaedar »

I've seen people liking the expansion of the universe to inflating a balloon with a smilie face on it. As the baloon gets bigger the face becomes bigger and more spread out but there's still something "in the middle" so to speak. Basically what G-flex said.

Time is relative. But to answer your question: Every place we can see seems to obey the same laws of physics as our immediate surroundings it is more or less assumed that this is the case for everything.

What exactly do you mean by "different"? Progresses at a different rate relative to ours? That is quite common(anything that moves at a different speed does this, technically)
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Re: Questions about the universe

Post by AEmer »

Alright, I'm gonna blow your mind.

You've heard this figure before: The universe is about 14 billion years old. Ok, so check this out. Einsteins theory of special relativity states that two objects may at most move 300.000 km/s away from each other.

This rule holds pretty much absolutely. This is why you cannot exceed the speed of light. It's really fucking weird, and reality is super tricky, because if you as a person travel near the speed of light, you will indeed feel like you're moving away from stuff faster. In fact, if you have a speedometer aboard your spaceship, it'll easily show that you're going faster. However, it's a trick! What actually happens is, time for you slows down. Everything feels normal, but in the time one hour passes for you, the object you're leaving behind experiences a day, a week, a month, or maybe a year. Effectively, you travel faster than the speed of light, but to the object you're leaving, you don't.

This is pretty common knowledge, it's been proven, and it's weird. Nothing may in fact travel faster than light - not even information. It's like life has a synchronization speed or some weird shit. Even gravity must adhere to this stuff.

Ok, so lets make things even weirder. Now you'd think that since the max speed is the speed of light, and since the universe is 14 billion years old, the universe can at most be 14 billion light years in diameter, right?

Wrong. See, reality cheats. Again. It's a fucking cheater is what it is. So check this out. We have this thing called the observable universe. The observable universe is what contains all the things with which we may eventually interact. I mean, that makes sense. If there's stuff that's 14 billion light years from us and that stuff is moving away from us at near the speed of light, then it's pretty reasonable that light from us will never reach them and vice versa. So you'd think, oh, ok, the observable universe is probably like 10 billion light years or something. Nope, wrong. The edge of the observable universe is about 46 billion light years from us. Whawhawhaaat? how the hell does that make sense?

Well, see, the universe is expanding. Not in the sense that we're flying through space, mind you. In the sense that shit gets bigger. It appears to get bigger proportional to the size that it already is, too. Yeah, bet you thought you were done growing. Nope. It's just that everybody else is growing too. So imagine you're a lightbeam now, and you're off to go grocery shopping in alpha centauri or some shit. So it's a bit away, so you head to the highway and start going. Only, even as you're going towards alpha centauri, the road ahead of you keeps growing longer. It's like you're traveling on a road on a balloon as the balloon is getting inflated. It makes no fucking sense, but fuck you, reality does whatever it pleases. You just gotta walk a bit longer.

So far as we know, this expansion of space, which is called the metric expansion of space for some reason, occurs all over. We can observe it. You know how blue light is a shorter wavelength than red light, right? So the wavelength of light is like a waveform coming in. Light that's coming in from far away is red shifted. This means that the wavelength of the light is longer than we would anticipate. In other words, we can tell that the light, as it is coming in, gets doled out over longer time as it reaches us than the time it took to make. The light is, effectively, getting stretched. This phenomenon is observable with sound and soundwaves, but it's also (in fact) observable simply from light that is moving. We have to account for it even in our gps system. It's also not like some weird drag coefficient that's slowing light down, because light from objects moving towards us is getting blueshifted - that is, it's wavelengths are shorter than we would expect.

The observable universe is that part of the universe which the distance to is not expanding faster than the speed of light. That's right; even though you can never move away from something faster than the speed of light, reality can grow so fast that it effectively increases the distance to something with more than a lightyear pr. year. Objects outside the edge of the observable universe, in other words, are getting further away so fast that we can never even see them.

This is some serious mind fuckery, but this means something else: There's galaxies where the light has been underway to us for 14 billion years or so and is only now just arriving. That light got sent out 14 billion years ago, at the start of the universe. It's taken this long to arrive due to the expansion of the universe. Examining this light is like looking into the past. The galaxies we see are no longer where they were when they sent the light, but that's not how it looks to us. It is, effectively, a window into the past of something really far away.
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Re: Questions about the universe

Post by Jaedar »

AEmer wrote:
This is pretty common knowledge, it's been proven, and it's weird. Nothing may in fact travel faster than light - not even information. It's like life has a synchronization speed or some weird shit. Even gravity must adhere to this stuff.
Actually....

Information can travel faster. I assume you've heard of quantum entanglement. If a photon does pair production and produces a particle and an antiparticle there's things that must be observed, one of which is spin. As weird as it sounds, measuring one of these particles determines what the other must be. Which has been confirmed by experiment. For a more everyday example see this: http://www.youtube.com/watch?v=lR4tJr7sMPM
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Re: Questions about the universe

Post by G-Flex »

AEmer wrote:So far as we know, this expansion of space, which is called the metric expansion of space for some reason, occurs all over
This may be concisely explained via an explanation of that term itself: It's called "metric expansion" because it's the metrics that are expanding. In other words, it's not that objects are moving away from each other, it's that all distances are increasing. Essentially, the scale itself is changing.
Jaedar wrote:
AEmer wrote:
This is pretty common knowledge, it's been proven, and it's weird. Nothing may in fact travel faster than light - not even information. It's like life has a synchronization speed or some weird shit. Even gravity must adhere to this stuff.
Actually....

Information can travel faster. I assume you've heard of quantum entanglement. If a photon does pair production and produces a particle and an antiparticle there's things that must be observed, one of which is spin. As weird as it sounds, measuring one of these particles determines what the other must be. Which has been confirmed by experiment. For a more everyday example see this: http://www.youtube.com/watch?v=lR4tJr7sMPM
Information still can't travel faster than light. Yeah, quantum entanglement is a thing, but for some reasons I haven't quite wrapped my head around yet, superluminal communication is still a no-go.
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Re: Questions about the universe

Post by AEmer »

What G-Flex says. Whilst it's possible to communicate over long distances via quantum entanglement, so far as I understand it, this information cannot actually be gleaned ahead of the speed of light.

That may be because quantum entanglement is actually a matter of particles, just as gravity has turned out to be with the higgs boson.

It would be real interesting to test if quantum entanglement might allow for communication with something on the other side of an event horizon..... it might be absolutely possible. After all, we do know of one particle which is able to escape a black hole: The Higgs Boson.
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Re: Questions about the universe

Post by G-Flex »

I can't confirm or deny that, but I do know that the Higgs Boson hasn't actually been proven to exist yet.
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Re: Questions about the universe

Post by Cybernetic pig »

G-Flex wrote:I can't confirm or deny that, but I do know that the Higgs Boson hasn't actually been proven to exist yet.
Nor has the Big Bang been proven to have happened. God made everything didn't you know. Ignorant fools, you will burn in hell for not believing.

I'm joking obviously. ;)
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Re: Questions about the universe

Post by DaveW »

Cybernetic pig wrote:
G-Flex wrote:I can't confirm or deny that, but I do know that the Higgs Boson hasn't actually been proven to exist yet.
Nor has the Big Bang been proven to have happened. God made everything didn't you know. Ignorant fools, you will burn in hell for not believing.

I'm joking obviously. ;)
Well, no, you're partly right - the 'Big Bang' is a theory as much as anything in science (Evolution / Gravity etc.) is a theory. Basically everything we know about the universe suggests the Big Bang, but it's not 100% proven.
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Re: Questions about the universe

Post by Cybernetic pig »

Of course I wasn't joking about the Big Bang being a theory.
My imitation of a god-fearing yella belly is what I was clowning around about, I thought that was obvious...?

It's all theories. We have been around for thousands of years, but still don't really know the answer to the big question.
There may be consequences to us knowing that answer though....
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Re: Questions about the universe

Post by Jaedar »

Information still can't travel faster than light. Yeah, quantum entanglement is a thing, but for some reasons I haven't quite wrapped my head around yet, superluminal communication is still a no-go.
Certain phenomena in quantum mechanics, such as quantum entanglement, appear to transmit information faster than light. According to the no-communication theorem these phenomena do not allow true communication; they only let two observers in different locations see the same event simultaneously, without any way of controlling what either sees.
http://en.wikipedia.org/wiki/Faster-than-light

So yeah, information can, communication can't apparently.
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Re: Questions about the universe

Post by Morpheus »

Cybernetic pig wrote:Of course I wasn't joking about the Big Bang being a theory.
My imitation of a god-fearing yella belly is what I was clowning around about, I thought that was obvious...?

It's all theories. We have been around for thousands of years, but still don't really know the answer to the big question.
There may be consequences to us knowing that answer though....
I don't remember a whole lot about it as it was so long ago, but a long time ago I watched Stephen Hawkings Universe and he explained everything in it, from time travel, to the theory of multiple universes (If I remember right he used string theory to prove there was multiple universes but not ones we could ever see or go to), to if there was a god. Changed how I thought of things. I do remember he said, before the big bang there was nothing as time didn't exist, so without time there was no time so nothing could exist, then everything appeared. Basically said the universe could create itself from nothing and no god was needed to create the universe. Bit more complex than that, but that was the main point.

Also, there is a theory of a big crunch, that all matter in the universe will eventually collapse in on itself http://en.wikipedia.org/wiki/Big_Crunch
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