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The universe is flat? Explain please!

Bjarki

Registered Member
I heard on TV additional evidence has been found that the universe is flat.
That sounds pretty odd, so I figured I'd look it up on the internet, but all I could find was vague news items or entire essays that got me lost in the first sentence :stare:

It's explained in the Scientific American here:
Distant Galaxies Confirm Dark Energy's Existence and Universe's Flatness: Scientific American

Can any of you science (with all respect!)-geeks explain to me what this is about?
In which way is the universe 'flat'? Should I take it literally and think of it as a sheet of paper? Or is it more like a pyramid with flat sides?
And wth does anti-matter have to do with it? (what does anti-matter do in the first place?).


Level: science for dummies.. for dummies :helpsmilie:
 

Hiei

The Hierophant
I'm going to be straight with you, I didn't read the article, but I can explain what anti matter is, for you.

Anti matter is pretty much exactly what it sounds like. Since the time of the big bang, there has always been anti matter present in the universe. It's created when there's an explosion on such a catastrophic level that it literally forces atoms to literally be blown through each other and make basically a negative version of itself. The thing that's most important to know about anti matter is that when it touches any non anti matter, it has a 100% reaction rate. So, theoretically, you could run your car forever with only a few grams of anti matter.



My personal beliefs almost prohibit the universe from being flat since I see the universe as stacked in levels that range from etheral, astral, and physical, physical being the highest level of reality that we can achieve.
 

9thEcho

Registered Member
I'm definitely the wrong type of science geek to be trying to understand this. I think I get the gist of what that article is saying, or at least trying to say, but it doesn't stop me wondering how the universe can be both infinite and flat. It seems to me that flatness would indicate a definite shape of sorts, or at least boundaries, and they wouldn't have any place in an infinite space... would they?

I think the only thing about that that makes sense to me was the stuff about how dark matter affects things. So, yeah, I'll add my plea to this as well, if someone could explain in simple terms what this is about, it would be great.
 

Bananas

Endangered Species
Can any of you science (with all respect!)-geeks explain to me what this is about?
No I cant, although I'll try :)


What they have done in this experiment is measured the common distance between near-by galaxy pairs and applied the common movement to distant pairs and using the difference between the two to calculate the amount of dark energy. Did that make sense?

Imagine you have a clock, you watch the hand go from 12 > 1, you measure the time it took for the hand to travel and a laser to measure the distance it travelled(eg 5 second and 5cm). now you place the clock at the bottom of a swimming pool and do the same experiment from the pool edge, it still takes 5 seconds to go from 12 >1 but due to the refraction of the water it appears to of travelled 6cm. With a bit of clever maths you could calculate the geometry of the water to cause this shift.

In which way is the universe 'flat'? Should I take it literally and think of it as a sheet of paper? Or is it more like a pyramid with flat sides?
As for the shape of the universe I think it has something to do with this principle;
http://aether.lbl.gov/www/classes/p10/gr/Curvature.html
...what im confused about though is are they claiming the universe to be flat like aas you describe, or flat as in space and time is the surface of the sphere and not the volume within it.

And wth does anti-matter have to do with it? (what does anti-matter do in the first place?).
Nothing. They refer to Dark Matter and Dark Energy which are different things altogether. Antimatter is the opposite to matter or what we liek to think is matter, although essentially both are the same, ie particles.

Dark Matter differs in that it does not contain any observable matter/particles, we dont really know it exists other than we assume it is there because something must be there (otherwise galaxies would not of formed the way they have).

Dark Energy is everything else, it is all the voids not made up of matter(normal, anti or dark), the energy describes whatever force dark energy has that forces everything from collapsing together.
 
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Bjarki

Registered Member
MSNBC reports:
Physics says the universe can either be flat like a plane, spherical like a globe, or hyperbolically curved like a saddle. Previous studies have favored the flat universe model, and this new calculation agreed.

Flat universe
The geometry of space-time can distort structures within it. The researchers studied observations of pairs of distant galaxies orbiting each other for evidence of this distortion, and used the magnitude of the distortion as a way to trace the shape of space-time.
To discover how much the galaxy pairs' shapes were being distorted, the researchers measured how much each galaxy's light was red-shifted — that is, budged toward the red end of the visual spectrum by a process called the Doppler shift, which affects moving light or sound waves.
The redshift measurements offered a way to plot the orientation and position of the orbiting pairs of galaxies. The result of these calculations pointed toward a flat universe.

Einstein's 'biggest blunder' turns out to be right - Technology & science - Space - msnbc.com
Hmm flat like a plane.. I need to readjust my perceptions of flatness or that just does not make sense? I mean if it's flat like a plane, how can the earth be a globe then? And the moon pass over it? :confused:

Why can't space and time behave normal for once? Damn you God! :mad:
 

Diederick

Registered Member
I'd like to recommend this lecture by Lawrence Krauss which he did for the Richard Dawkins Foundation. It's pretty long, but it's also the best and simplest explanation I could think of.
...but it doesn't stop me wondering how the universe can be both infinite and flat. It seems to me that flatness would indicate a definite shape of sorts, or at least boundaries, and they wouldn't have any place in an infinite space... would they?
I don't think any modern astronomer would suggest the universe is infinite, because that is impossible. But let's forget about that, supposing there would be something infinite about the universe, it could still be flat. It would be like a sheet which sides do not exist and so it extends forever. And I think you should not think of a flat universe as a large piece of paper...
Hmm flat like a plane.. I need to readjust my perceptions of flatness or that just does not make sense? I mean if it's flat like a plane, how can the earth be a globe then? And the moon pass over it? :confused:
Because it is flat, but not two-dimensional. It is still three dimensional, space still has a thickness. It's shape is simply flat, not spherical or pyramid-shape, but just quite flat.
 
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Bananas

Endangered Species
MSNBC reports:


Hmm flat like a plane.. I need to readjust my perceptions of flatness or that just does not make sense? I mean if it's flat like a plane, how can the earth be a globe then? And the moon pass over it? :confused:

Why can't space and time behave normal for once? Damn you God! :mad:
Euclidean geometry - Wikipedia, the free encyclopedia

Flat does not at any point mean 2D, the surface fo the earth is "flat", it may wrap itself around into a spherical shape but the surface is flat. You can also use this analogy to explain how if the surface was perfectly smooth and you walked in one direction, you would remain on the spaital plane neither going up or down, but observed from the moon you would of done a full circle. This is kind of what they mean by "flat" the universe is 4D but we translate this into 3D/2D geometric descriptions to try and understand it.
 

9thEcho

Registered Member
I don't think any modern astronomer would suggest the universe is infinite, because that is impossible.
See now that just confuses me even more. On one hand, I can understand how that can be impossible, but on the other, if the universe isn't infinite then what is it exactly?

I think I do kind of get the rest of it now, although I think, like Bjarki, I'm going to need to readjust my perception of just what flat is. It might sound slightly dense now, but to me flat and 2D were the same thing. And 4D? Yeah, definitely need to adjust a few things here so I can understand that properly.
 

Hiei

The Hierophant
I think I understand how the universe can be "flat" now. There is no edge of the universe because it's really spherical or some such "shape." What confuses me, though, is the possibility of multiverses. If our universe is flat as in spherical, then that would mean that there's something outside of our universe. What would the space between universes be called?

I think in that such a fashion, the grand scheme of universes would be infinite. An infinite amount of universes inside an infinite amount of multiverses. I think my head is going to explode soon.
 

9thEcho

Registered Member
What confuses me, though, is the possibility of multiverses. If our universe is flat as in spherical, then that would mean that there's something outside of our universe. What would the space between universes be called?
I think this is the more intelligent version of the question I was attempting to ask.

I think in that such a fashion, the grand scheme of universes would be infinite. An infinite amount of universes inside an infinite amount of multiverses. I think my head is going to explode soon.
I think that actually makes the most sense (to me) out of everything in this thread. It's definitely a huge concept to get around, but I can understand it without knowing the hows and whys of it all.
 
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