What is the nature of the boundary of the cosmos (universe)?

Question

I keep getting theories, but I am hoping for things we can be more sure of; but theories are good provided you can explain how is the nature of the boundary of the cosmos with respect to your theory.

It seems to me photons can not travel into an infinite void, but they always come to some atom somewhere eventually, otherwise the universe would not be able to conserve its matter and energy.

Our solar system seems to be at or near the center of dispersion because otherwise the most distant visible stars would appear to converge over time.

There are various dimentions in a mathematical sense but there are only 3 component reference dimentions of spacial vectors. I agree that a bug on the inside of an inflated baloon can travel along the boundary, as an analogy; but what is the nature of the boundary, considering space should only be more curved under gravitational fields?

Since then space is least curved at the "boundary" then how could our explanations of the boundary hold?

Answer 1

1.) Nature of the boundary of the Cosmos...
No one knows. No boundary has ever been detected, measured, calculated, or observed.

2.) Photons travel in a straight line unchanged until they strike some object, unless pulled off course by some object with immense gravity. In the later event, the path of the photon is bent slightly and then it keeps on going in a straight line thereafter. There is no loss of energy. All the energy that was here is still here, just more dispersed than before. Take a big box of 144 ping pong balls and drop it onto the floor such that the box bursts and balls fly out everywhere. You no longer have a box of 144 ping pong balls. But, you still have the box, and you still have 144 ping pong balls...They are just not all mashed together in the box like before.

3.) Our Solar System is not at the center of the dispersion.

4.) The most distant stars do not appear to converge. They are measured as moving, spreading out farther and farther.

5.) A bug in space moves in three dimensions. However, a fourth dimension is also required since everything is moving within the Universe. That fourth dimension is time. If you were to look at Haley's Comet for example and steer you space ship straight at it where it is right now, and push the button for ignite engines...traveling at some fast speed for a long long time...when you got to where Haley's Comet was, Haley's Comet would be long gone since it is moving at a fast rate of speed. So, you must factor into your discussions the orbit of these objects and where they are at this moment, plus calculate where they will be at some particular time in the future...TIME.

6.) No explanations of the boundary have ever been given in Astronomy texts.

7.) The universe as we know it today has a "seeable" distance of 40 Billion Light Years in every direction from Earth. Things may be seen out to that distance using our most sophisticated optical and radio telescope devices. Beyond that distance our equipment fails to produce any useable information. Maybe some new models of equipment will come down the line in a few years which will extend that distance out somewhat, possibly to 60 Billion Light years or so... My point is, why do you even care what lies beyond a distance of 40 Billion Light years??? No one is ever going to travel out that far. A radio message out to some place way out there would take 40 Billion years to arrive... So, what is the point?

Answer 2

In Cosmology, words can take on different meanings, and have different implications than they have in ordinary life, and "boundary" is one of those words. For example, in every day life there is something on each side of a boundary. However, if you say the Universe is everything that there is, then if the Universe has a boundary, by definition there is nothing on the the other side of the boundary. Another example: One can say that the Universe has a boundary at the beginning of time, and if the Universe eventully contracts back on itself, it will have a boundary at the end of time, and there will be nothing on the other side of either boundary, before or after the Universe.
Its more difficult to visualize in space. The surface of the Earth is a boundary in space with no beginning or end, and it is also curved so you can somewhat see how a space can be curved to create a boundary.
I find the case of an unbounded Universe to be even more confusing. One can always visualize a 3 dimensional infinite Ecludian space that goes on out in a stright line forever without any boundary. We tend to think of the Universe as somehow occupying this space. This may or may not be an accurate visualzation.
I have labeled my personal opinion on the case of the unbounded Universe "All Creation All the Time." I believe that we exist in one Universe of many which are all part of a larger constantly expanding Mulitverse. Our Universe is expanding along with the Multiverse. New Universes are constantly being created in the Multiverse. Some of these Universes are similar to our Universe and some are not at all similar. The Multiverse is very very large, and as it expands, it approaches infinity is size, although it will never be infinte. There is no boundary to our Universe or the Multiverse, and the geometry of both is something like the following:.
If you had a space ship traveling at the speed of light you could try to approach the edge or boundary of the Universe but you would never reach it, because the space in front of you will expand faster than you can travel through it. Thus, even if there were a boundary to the Universe, you could never reach it, experience it, or be affected by it. This situation can be expressed mathmatically (not by me), and is equivilent to a no boundary condition.
Now, are you less confused about boundary issues?

Answer 3

The words "boundary" and "universe" are incompatible with eachother. Universe means everything, and boundary suggests additional things. If there was a boundary, then anything beyond the boundary would be part of the universe! So it is self contradictory. Similary the words "photon" and "travel" are incompatible. There is no proof that photons move at all. Once detected, they die. For example, we can predict that a photon which eminates from the sun at a particular time will be a certain distance from the sun "x" at time "t". However to prove it is there, we need to detect it. Once detected, it's "journey" has ended, so we cannot determine where it will be after an additional time "T", since it no longer exists. So, how can we know it has eminated from the sun in the first place, since we can't detect it as it "leaves" the sun...if we do, we destroy it!

Anyway, MY crazy theory about the universe is that there is only one END to my universe (I mean in space, rather than time). That end is where I am at any instant. I carry MY end with me wherever I go. So, let's imagine that I travel a gazillion miles thattaway------->> When I get there, I STILL have MY end of MY universe with me, and the universe extends out in every direction, all around me. I can repeat this as many times as I like and still MY end of MY universe will be with me. So, I believe MY universe is semi-infinite! It has only one end!

Answer 4

You have an excellant question here, but i'm not going to say that what I am telling you can't have some tweeking to get it much closer to exact.

First no one has been to the extreme limits of our universe, though in photography from land based telescopes, if you go as far as electrically and photographically possible to go, you strike a wall of white light, a curtain as it were.

When NOVA was exploring this, they interviewed a scientist who said that with new techniques, they were able to adduce that the white vail or cloud, is galaxies so numerous as to be uncountable. The distance involved is beyond my memory to recall.

The astronomer was saying that as far as astronomy is concerned, the universe is infinate, there is no loop as predicted.

Now as to the photon striking something, that may be the case, but how do you age a photon anyway. You can talk redshift, but that is speed, not the characteristic of the actual photon. No one can tell you that.

I know you are thinking i=c/(d squared), but the facts don't support that.

Also, the japanese and united states within the last 20 years, proved that the conservation of energy is not correct (see scientific american). Energy dies...no joke.

Based on the best information available to me, the boundry does not exist in terms that mean anything to people.

Carl Sagan took a great deal of joy in the vastness of the universe, you might look up some what he had to write about the subject.

Answer 5

Photons can fly into an infinite void, because as soon as they fly into it, it is the same space as everyone else knows it. Following are two very good descriptions of the expanding universe and how it expands:

1) Space is constantly expanding. Where a given galaxy was when you wrote your question is where it is now. For one thing, this means that no matter which galaxy we are talking about, virtually all of the other galaxies are moving away from that galaxy. The universe has no "edge" as such. It also means that the galaxies are not moving away through space, they are moving away with space (with space being created between them), as space itself expands. Think of a loaf of unbaked raisin bread you've set in a warm place to rise. The raisins are like galaxies or clusters of galaxies, and the dough, space. As the dough rises, the raisins move farther apart, but they've moved with the dough as the dough expended, not through the dough.

http://archive.ncsa.uiuc.edu/Cyberia/Cosmos/ExpandUni.html


2) "The mother of all horizons--the one at the edge of the cosmos--is set by the speed of light and the age of the universe. No matter our technology or technique, we cannot see farther away than the object whose light has traveled 13 billion years to reach us, because the universe is only 13 billion years old. This cosmic sphere, with a radius of 13 billion light-years, is centered in space and time on whoever is making the observation. Moving at the speed of light, the expanding horizon continuously overtakes parts of the cosmos that were previously on its other side. In a billion years, when the universe is 14 billion years old, we will have seen another billion years of cosmic evolution at every distance between here and there, and we will have seen another spherical shell of cosmic material that has undergone the big bang and given birth to galaxies. The galaxies whose light will have taken 14 billion years to reach us will come into view only after the universe has reached 14 billion years of age. Since the entire universe, including the parts beyond our cosmic horizon, participated in the big bang, then the cosmic background radiation will always remain in view, albeit at an ever increasing distance, and there will always be a crop of galaxies caught in the act of forming."

http://findarticles.com/p/articles/mi_m1134/is_2_108/ai_54032997/pg_2

Answer 6

back in the day it was ether, i always made a joke about ether its there or ether its not, i suppose in short the answer would dark matter. but who knows i am no einstein

Answer 7

Exactly.