What happens when a ray of light hits the boundary of the universe?

[cragar]

isn't everything in our universe 4d

 

[havonasun]

Stalon, that's where I got tripped up. It's a real paradox, its a boundary that is there but doesn't exist. The void or nothingness, by definition, can't be pointed to; you just end up pointing at the back of your head.

if the universe that we see and perceive in any possible way through our instruments finishes at 13 or 15 billion light years around, then that is the boundary and light can never escape that.

Until the following year when the Pro version comes out and then we can see 18 billion ly! That is the strangeness of this concept; light can't escape because there's nothing to escape. A beam of light will travel in a straight line through this universe for eons of eons and never reach the end. Its like Asteroids on Atari when your ship goes off the edge and appears on the other side of the screen.

I might still be wrong, everyone feel free to correct this.

 

[cragar]

A beam of light will travel in a straight line through this universe for eons of eons and never reach the end.

light would eventually come back around to where is was emitted .
There is a book called Mr. Tompkins in wonderland written by the physicist George gamow
and he talks about throwing a book off a planet and seeing it go away from the planet
it gets smaller and smaller as it goes away , then it starts to get bigger again then it appears as if it is right next to the person that threw it , he reaches out to touch it and he can't , because the lights rays are converging just like the meridian lines on our globe
when we see the imaginary image next to us the book is halfway around the universe
and then it eventually comes back to use , This would happen in our universe
it would just take a long time .

 

[havonasun]

Yep, that's what I meant. I love the mental visuals from paraphrase you gave. I think I'm going to look that book up.

 

[stalon34]

I just don't understand why havonasun keeps insisting on light traveling on a straight line. straight line is a very old and wrong concept. it has been proven that there is no such thing as straight line any where in universe due to the presence of gravity. if we accept straight line then we have to believe that our universe is a flat plane. while flat plane, straight line and point are only abstract mathematical concepts and not physical reality. every thing in universe is 3D; mathematical concepts are 2D. True way of knowing our universe is to collect the actual and factual observations and then allow these observations lead us towards imagining the unobserved aspects or features of our universe. In plain words, observe and then imagine the unobserved parts. What you guys are doing is quite the opposite. You guys plunge yourselves right at the start into a type of universe that is supported by nothing but your pure imagination.

 

[peterdorey]

It's all just movement in Stillness & stillness in Movement (a bit of Manhamudra there).
With e-m radiation "sloshing" around (this sentence loosley quoting ProfBECox seem to recall).

 

[Skaffen]

The only constant is change.

The Universe is 'Infinitely Bounded'. - Just as explorers (hundreds of years ago) thought there was an edge to the world, contemporary scientific observations lead us to think we have found the edge of the Universe...Dark Energy anyone?

From recent images (Keck, I think), the observable Universe appears to be an oblate sphere, which to me suggests it is spinning (Why not? Everything else does). This spin would imply a greater shearing force the further from the origin (Increased radius), hence the observed increased acceleration in spatial expansion over Time.

The balloon analogy invokes an inflationary process which does not address the principle of Conservation and consequently is misleading - a more useful description is to term it 'unfolding'...like an umbrella being spun.

Imagine a planet composed of a perfect liquid that is disturbed by a pebble (breaking symmetry) - the wave would reach the pole and make it's return journey 'indefinitely', however all is connected so the energy is transferred partially to another 'object' and the result/remainder is returned to the origin (feedback)..and evolves, becoming increasingly complex and diverse until it stabilizes through synchronisation.

Gravity is the tension of our liquid, light is the breaking of the wave.