Jump to content

Recommended Posts

Does our universe expand in all directions equilaterally? Would that give the universe a centre?

Link to post
Share on other sites
Thank you for your support
Buy Ex-C a cup of coffee!
Costs have significantly risen and we need your support! Click the coffee cup to give a one-time donation, or choose one of the recurrent patron options.
Note: All Contributing Patrons enjoy Ex-Christian.net advertisement free.
  • Super Moderator

The "center" of the universe can be anywhere. It's really a meaningless term since there are no boundaries. There is nothing beyond the universe for it to expand into. I'm not a physicist, but I can get YouTube.

Link to post
Share on other sites
10 hours ago, AntiChrist said:

Does our universe expand in all directions equilaterally? Would that give the universe a centre?

That would be "The Donald"

  • Like 2
  • Haha 2
Link to post
Share on other sites

This video might help, AC.

 

https://www.youtube.com/watch?v=69EUgdj7lzI

 

Cooper thinks that the wormhole is a circular hole in space, but Rom explains that they're dealing with higher dimensions than the 3D space humans are used to.  That's how it is with cosmology, when it comes to the universe.  Don't think of the universe as a 3D sphere, with a centre and a boundary.  Instead, think of it as a 4D hypersphere, with no centre and no boundary. 

 

Don't worry if you can't visualize such a thing.  The human mind can't really get to grips with anything other than 3D.  But scientists use higher-dimensional mathematics to try and understand how it all works. 

 

Please take note than when the Endurance enters the wormhole it doesn't dive in, at right angles, like a car going into a tunnel.  No.  Instead the Endurance makes its approach at a tangent, following a grazing trajectory that causes it to enter the wormhole at a very shallow angle.  Yet, when we cut to see the inside of the wormhole, the Endurance is fully within what looks like a distorted tunnel.  

 

If the wormhole really was just a 3D sphere, then they wouldn't be able to see the walls of the tunnel all around us.  What they should see is the boundary they've just crossed, behind them.  But because its a 4D hypersphere, the moment they crossed the spherical 3D boundary they left 'normal' 3D space behind. The rules change.

 

So it is when it comes to understanding our universe.  We live inside it, in 3D space, but you need 4D space to properly describe its true shape. And for that you leave your 3D brain behind and use 4D maths.

 

Sorry, but there it is.

 

Thank you.

 

Walter.

 

 

  • Like 2
Link to post
Share on other sites
  • Super Moderator
29 minutes ago, MOHO said:

That would be "The Donald"

The law of entropy suggests you are correct.

  • Haha 2
Link to post
Share on other sites
4 hours ago, florduh said:

The "center" of the universe can be anywhere. It's really a meaningless term since there are no boundaries. There is nothing beyond the universe for it to expand into. I'm not a physicist, but I can get YouTube.

So you'd be saying I'm the centre of the universe. :D

  • Haha 2
Link to post
Share on other sites
  • Moderator
On 7/15/2020 at 3:35 PM, AntiChrist said:

So you'd be saying I'm the centre of the universe. :D

 

Well, sort of. The christians are both right and wrong. We are the center of the universe, but so is everywhere else too!!!

 

🤣

 

Sort of right, but ultimately wrong...

Link to post
Share on other sites
On 7/15/2020 at 12:04 AM, AntiChrist said:

Does our universe expand in all directions equilaterally? Would that give the universe a centre?

 

There are variations of prevailing theory. The majority think the universe curves into a fourth dimension, and if so there is no center to it. If you travel in a straight line from any starting point, you would end up back where you started. If the universe does not curve into a fourth dimension many think it is flat. Flat means that it is three dimensional and would have a center to it if it is limited in its size.

 

Even the expansion of the universe is just theory, primarily the Big Bang theory. But the competing theory in the 1960's was called the Steady State theory, which also proposed the universe was expanding. But there are many dozens of other theories that few have heard of, which propose other reasons for the observed galactic redshfts other than an expanding universe.  Most theorists believe the universe is expanding equally in all directions.

 

The famous astronomer Erwin Hubble essentially discovered galactic redshifts in 1929 and is credited with discovering the expanding universe. But he himself believed that there was another reason for these redshifts other than an expanding universe. A great many alternatives have been proposed to explain galactic redshifts other than an expanding universe.

 

https://www.science20.com/eternal_blogs/blog/hubble_eventually_did_not_believe_big_bang_associated_press-85962

https://rationalwiki.org/wiki/Alternative_cosmology

 

 

  • Like 1
Link to post
Share on other sites
  • Super Moderator

If the universe is all that is, what would it expand into? The universe that could expand would have to have an outer boundary and therefore couldn't be THE universe but perhaps a smaller universe inside the REAL universe. I think the problem here, with both us and the scientists, is humans are incapable of visualizing or understanding in any way the concept of infinity.

  • Like 1
  • Thanks 1
Link to post
Share on other sites
10 minutes ago, florduh said:

If the universe is all that is, what would it expand into? The universe that could expand would have to have an outer boundary and therefore couldn't be THE universe but perhaps a smaller universe inside the REAL universe. I think the problem here, with both us and the scientists, is humans are incapable of visualizing or understanding in any way the concept of infinity.

Interesting, but how does this other external universe exist without being bound by the same logical dilemma this one has.

 

It's called the Farnsworth dilemma.

  • Thanks 1
Link to post
Share on other sites
  • 2 weeks later...

The oversimplified version I heard is imagine a computer monitor where if you move your mouse cursor off the left hand side it re-enter from the right hand edge. You can move unrestricted in any direction but if you travel far enough your cursor will cross the point it started. The field it is on is limited in scope, but with wrap around you can travel infinitely and never hit the edge. 

Link to post
Share on other sites

Or you could take the example of a sphere, across which you can travel infinitely and never hit an edge, and think of us as living within the surface of the sphere, not inside its volume.

 

We have no trouble understanding that flat humans in a photo are just 2D representations of a 3D reality.

 

So the reality we inhabit could be just a 3D representation of the 4D reality.  A finite universe you can travel within and never meet an edge.

 

That's if you want to treat the universe as finite, but unbounded.

 

But if it really is infinite, then don't bother with any kind of boundary or edge.

 

Thank you.

 

Walter.

Link to post
Share on other sites
  • Super Moderator

I thought the universe was shaped like a sideways "8".

infinity.jpg

  • Thanks 1
Link to post
Share on other sites
On 7/15/2020 at 2:04 AM, AntiChrist said:

Does our universe expand in all directions equilaterally? Would that give the universe a centre?

 

Excellent questions. Let me address them in order.

 

"Does our universe expand in all directions equilaterally?" I'm guessing you meant "equally." Yes, the universe does expand equally in all directions. This is related to the observational principle known as Hubble's Law, which states that the recession velocity of distant galaxies is proportional to their distance from earth. In astrophysics we make this determination using a sort of stepping stone approach. The distance to nearby stars can be determined using the Method of Parallax. The same star, observed six months apart, will appear in a slightly different position in the sky because the Earth has moved with respect to the sun. Using Euclidean geometry and the known radius of the earth's orbit, we can deduce our distance from the star.

parallax_1.png

(Source: http://spiff.rit.edu/classes/phys443/lectures/parallax/parallax.html)

 

But, some stars are far enough away that we can't detect the parallax. That's where a certain class of stars known as Cepheid Variables comes in. A Cepheid Variable, as the name implies, is a "variable star," in that its brightness as viewed from earth - or magnitude, as we astronomers call it - varies with time. For Cepheids, that magnitude has a predictable period. It turns out that the luminosity of a Cepheid variable depends on its period, as shown in the below diagram:

http://hyperphysics.phy-astr.gsu.edu/hbase/astro/cepheid.html

(Source: https://socratic.org/questions/why-is-a-cepheid-variable-star-referred-to-as-a-standard-candle)

 

We don't know - a priori - how far away a distant star is. So a dim star that is very close to earth could have a smaller magnitude* than a bright star that is very far away. But in the case of Cepheid Variables, we can measure their distance and their magnitude, and thus infer their luminosity, i.e. the total amount of light emitted by the star (if you know how far away a star is and you know how much light you are receiving at Earth, you can know the luminosity). The period-luminosity relationship was determined by looking at Cepheid variables for which we have parallax measurements. That means that if a Cepheid is far enough away that we can't measure its parallax, we can still know its distance by measuring its period. That lets us look at Cepheids in other galaxies, and know how far away are those galaxies!

 

Finally, we can look at Cepheids in galaxies that are at moderate distances, and determine their distances based on the periods of the Cepheids. We can also look at the energy spectra of light emitted from those galaxies, and look for spectral signatures. For example, we know that hydrogen electrons emit light at specific frequencies associated with electronic transitions. We know the frequencies by observing hydrogen in a lab. But if the hydrogen atoms are moving at high speeds close to that of light, those emission frequencies are shifted. By observing the new frequencies, we can know the speed of the hydrogen atoms. It turns out that if you look at galaxies that are sufficiently far away, the galaxies are always moving away from Earth. by looking at the nearby galaxies and determining their distance from the Cepheids, you can learn the mathematical relationship between distance and recession velocity. So now you can look at galaxies that are much further away - at distances where you can't resolve individual stars - but you can still know how quickly they are moving away from us based on the spectral signature. See the following diagram for an illustration of this effect:

 

hubbles_law.gif

(Source: http://hosting.astro.cornell.edu/academics/courses/astro201/hubbles_law.htm)

 

This effect isn't necessarily true for close by objects. For example, I am not receding from you, and the nearby Andromeda Galaxy is not receding away from us (in fact it is rushing toward us). But at larger distances where the expansion of the universe is more important, all galaxies move away from us.

 

So to your second question: does this mean the Earth is the center of the universe? No! The interesting thing about this observation is that it is fully explainable by Einstein's Theory of General Relativity. Said theory shows that if you lived in one of those distant, receding galaxies, you would observe all galaxies moving away from you. It would appear that you were the center of the universe. You have probably heard that according to the Theory of General Relativity, space and time are viewed as a single entity, which can be likened to the malleable fabric of the universe. Think of spacetime as a balloon being inflated, and imagine making multiple marks on the balloon with a sharpie. As the balloon is inflated, an observer at each mark will see the other marks moving away from it. Yet no observer is at the "center" of the balloon, and we needn't even imagine the balloon expanding into anything else, because for the purpose of our analogy the surface of the balloon is all that matters (if you ever study differential geometry, this is referred to as a "Riemannian manifold").

 

tl;dr. The universe is expanding in all directions from the vantage point of the Earth, and that does not mean the Earth is the center of the universe.

 

*For historical reasons, magnitude is defined so that smaller numbers represent brighter objects. So -4 is brighter than 2 is brighter than 6, etc.

  • Thanks 2
Link to post
Share on other sites

/thread.

Link to post
Share on other sites
On 7/15/2020 at 12:04 AM, AntiChrist said:

Does our universe expand in all directions equilaterally? Would that give the universe a centre?

 

The universe has a creamy center made of nougat. 

 

 

  • Thanks 1
  • Haha 1
Link to post
Share on other sites
19 minutes ago, midniterider said:

The universe has a creamy center made of nougat.

I think you are thinking of the Galaxy:

 

galaxy-smooth-milk-chocolate-bar-removed-from-wrapped-to-show-contents-BKX7T1.jpg

  • Like 1
  • Haha 2
Link to post
Share on other sites

Hmmm...

 

How come you guys can post these images, yet when I try and do so I get told that I'm limited to 20.4 k, which is tiny..?

 

Walter.

 

 

Link to post
Share on other sites
  • 1 month later...
12 hours ago, alreadyGone said:

I heard somewhere that the answer is 42.

 

 

What does 42 mean in the context of this thread. I can answer your question or comment if I understood it.

Link to post
Share on other sites
  • Super Moderator
20 minutes ago, pantheory said:

 

What does 42 mean in the context of this thread. I can answer your question or comment if I understood it.

Don't Panic.  It's an allusion to "Life, the Universe, and Everything," part of the Hitchiker's Trilogy, by Douglas Adams.

Link to post
Share on other sites
  • Moderator

This is an interesting topic with some solid informative answers. Should it be moved to the science section?

Link to post
Share on other sites

 

Thanks RNP,

 

16 hours ago, TheRedneckProfessor said:

Don't Panic.  It's an allusion to "Life, the Universe, and Everything," part of the Hitchiker's Trilogy, by Douglas Adams.

 

I guess by my question it's obvious I never read any part of that trilogy

Link to post
Share on other sites
13 hours ago, LogicalFallacy said:

This is an interesting topic with some solid informative answers. Should it be moved to the science section?

 

As for me, I can find such interesting topics better in the science section, but maybe others that are interested could find it better in the Questions section. I think you would be the best judge of this.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Guidelines.