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Bill32
2003-Nov-12, 05:35 PM
My dad is writing a sci-fi book. We constantly have disputes over his idea of "sci-fi". In his book, an outpost(humans) live on the last planet of their solar system. If the inhabitants look in one direction - they see stars and galaxies. But, if they look in the opposite direction - they see nothing !!! In another words this planet exists at the very edge of our universe !!! Looking in the opposite direction gives a person a view of space that does not, nor ever have contained stars, planets or galaxies !!!

How does my explaination of this planet, at the edge of the universe, conform to actual science, and what we know of the universe ??? That is, would it be possible to travel from Earth (in a sci-fi space craft)so far that you find yourself looking back at the stars ??? - and see no stars in front of you ??? (Sort of like when you drive away from a major city, and look back and see the city lights, then look forward and see nothing but the blackness of the desert !!!)

Please respond. Thank you. :blink:

GOURDHEAD
2003-Nov-12, 07:29 PM
;) The universe likely has no edge so what you postulate is like listening for the sound made by one hand clapping (not to be confused with Wan Hahn clapping). A reasonable metaphor is looking far an island at the edge of the surface of the earth.

A more likely case would be a planet in a stellar system on the outer edge of a galaxy which is itself at the exterior edge of a group of galaxies at the exterior edge of a super cluster of galaxies sufficiently far from the next supercluster such that the stars in the next supercluster are not detectable without the use of very sensitive instruments.

<_<

Planetwatcher
2003-Nov-12, 08:40 PM
I aggree with GOURDHEAD.

Such a planet is possible, however it would not likely be within the life zone of the star. So artificial life support such as domes would have to be used. B)

Haglund
2003-Nov-12, 10:26 PM
Why would it not be in the life zone of the star?

Josh
2003-Nov-12, 11:36 PM
The edge of our solar system and the edge of the galaxy and the edge of the universe are VERY different things. I don&#39;t see why humans living at the last outpost in out solar system would mean they are at teh edge of the universe. Fair enough they won&#39;t see the inner planets but there are many other galaxies and comets to be seen when looking the other way.

And as to GOURDHEAD&#39;s comments...i say...Spot on. The universe is like an extra-dimensional planet in the respect you&#39;re talking about. An island at the edge of the planet - ie the surface- is exactly where you expect to find islands. In this case of the universe and the bodies within it there is not underground or sky analogy .. only the surface. So ... there is no edge of the universe&#33;

imported_ROB
2003-Nov-13, 08:43 AM
[The universe likely has no edge so what you postulate is like listening for the sound made by one hand clapping (not to be confused with Wan Hahn clapping). A reasonable metaphor is looking far an island at the edge of the surface of the earth]

totaly agree
I cant remember where i read the link but its on the internet somewhere, It made a statment that said the universe was spherical as it expands so that if you set of from earth in one direction eventually you would arrive back at the same spot you started

imported_ROB
2003-Nov-13, 08:47 AM
[QUOTE
I cant remember where i read the link but its on the internet somewhere]

found it it here

the universe (http://www.newscientist.com/news/news.jsp?id=ns99994250)

rob,

Matthew
2003-Nov-13, 09:05 AM
You cannot get to the edge of the universe. It may have one, but you cannot reach it.

Sp1ke
2003-Nov-13, 10:27 AM
Since the universe has been expanding since the big bang, you could say the edge is the outer limit of the expanding universe. Two problems with this: there&#39;s nothing beyond the edge since space-time only exists withing the universe, and the "edge" is expanding at the speed of light so there&#39;s no way to catch up with it nor to see anything when you&#39;re there.

Haglund
2003-Nov-13, 10:53 AM
There&#39;s no real edge like the universe was a balloon or something, and it&#39;s likely that you will never reach the end of the universe, you would go in one direction forever, returning to the same position over and over again.

Menikmati
2003-Nov-13, 06:08 PM
That is, would it be possible to travel from Earth (in a sci-fi space craft)so far that you find yourself looking back at the stars ???

If the universe was to be flat, then yes.

Planetwatcher
2003-Nov-13, 07:50 PM
Why would it not be in the life zone of the star?
I wouldn&#39;t think of the edge of a solar system as being within the life zone, although I won&#39;t say it&#39;s impossible. But I was also thinking about the recent story of Voyager 1 encountering the helopause of our solar system.
Wouldn&#39;t it stand to reason that all stars have some kind of helopause? Which for the most part would define the edge of that star&#39;s solar system. And likely us as well if not for the Orrt Cloud.

Anyway, I wouldn&#39;t imagine a life zone planet could harbor life if it were in it&#39;s system helopause. Even if supported by artificial life support, it would seem to me that a helopause would cause some kind of disturbances in the planets natural order and or movement patterns. But I am presuming with no real evidence to back my presumptions. Just thinking with the keyboard.

starrman
2003-Nov-14, 10:45 PM
In current cosmological understanding, it&#39;s a bit misleading to employ the term "edge" to concepts of the geometry of the universe. That said, one can consider that there is, in fact, an "informational edge" to the region of the universe which we earthbound observers can reach. At this time, best estimates for the age of the universe range in the area of 12 to 14 billion years. Thus, the most distant objects about which we can obtain information must reside within a spherical region centered on the earth with a radius of ~ 14 billion light years. Any objects more distant than that lie outside our "sphere of information," that part of the universe within which electromagnetic radiation - light, radio and microwaves, gamma radiation, etc. - has had time to arrive at our location. By definition, anything beyond that spherical volume of the universe cannot be known to us, and so might be said to lie "beyond the edge." Or at least beyond our local edge.

Clear skies.

corkft
2003-Nov-15, 02:51 AM
For a good indication as to the true nature of the Universe, I would suggest reading the series "A Hitchhikers Guide to the Universe".

Josh
2003-Nov-15, 02:58 AM
Heh ... not only will you find the answer to the true nature of the universe but possible answers to todays simple questions like "what is the meaning of life?"

Tinaa
2003-Nov-15, 03:19 AM
I would quit arguing with your dad. You said it was a sci-fi book. He can make up his own rules in his universe. No one really knows if, when or where the edge is or isn&#39;t. Maybe the edge would look like a bubble from the inside.

Haglund
2003-Nov-15, 08:47 AM
Originally posted by Planetwatcher@Nov 13 2003, 07:50 PM

Why would it not be in the life zone of the star?
I wouldn&#39;t think of the edge of a solar system as being within the life zone, although I won&#39;t say it&#39;s impossible.

Ok, if the planet is on the edge of its own solar system that would most likely be right.


But I was also thinking about the recent story of Voyager 1 encountering the helopause of our solar system.
Wouldn&#39;t it stand to reason that all stars have some kind of helopause? Which for the most part would define the edge of that star&#39;s solar system. And likely us as well if not for the Orrt Cloud.

Anyway, I wouldn&#39;t imagine a life zone planet could harbor life if it were in it&#39;s system helopause. Even if supported by artificial life support, it would seem to me that a helopause would cause some kind of disturbances in the planets natural order and or movement patterns. But I am presuming with no real evidence to back my presumptions. Just thinking with the keyboard.

No, of course not. Not life as we know it anyway... I&#39;m not sure that GOURDHEAD said that it would be at the edge of the solar system but only at the edge of its galaxy, and the galaxy being on the edge of its supercluster.

Josh
2003-Nov-15, 08:58 AM
Bill32 sent me this email...


What about "farthest reaches"? That is, when the big bang occurred, the
universe expanded from that "point" outward. And, the universe is still
expanding. For hypothetical purposes, if I had a sci-fi star ship that could
get me to the "farthest reaches" of our known universe, i.e. get me to the "big
bang shock wave" or "wave front" - WHAT WOULD I OBSERVE? COULD I LOOK BACK ON
THE WAVE FRONT AND OBSERVE THE UNIVERSE, AND THEN LOOK FORWARD AND SEE
ABSOLUTELY NOTHING (because the universe has not expanded past this "front")?
If I had this hyper-speed ability, could I drive my star ship into the space in
front of the "big bang wave front"? Or, is this space not yet created, because
the "wave front" did not reach this area?

The answer, as far as we know the nature of the universe to date, is that you would look back and see the universe and look forward and still see the universe. The &#39;big bang&#39; was not an explosion with a point source that spread like we understand normal explosions of bombs etc. It was an explosion of space. not and explosion into space. This is also true given that the universe is likened to a computer game screen where things can go out of one side of the screen and in the other side. Like one of the so called "edges" (of which there are none) of the universe is linked to the other edges. If you travelled far enough in one direction you&#39;ve eventually come back to your starting point. Making any sense?

There are a number of other threads that this has been spoken about in. If you do a search for the phrase "big bang" in the search bar then you&#39;ll very likely hit upon the threads I&#39;m talking about. They&#39;re really quite interesting.

Matthew
2003-Nov-15, 09:10 AM
Could it be 42? :P

Planetwatcher
2003-Nov-15, 03:21 PM
No I don&#39;t suppose life as we know it could exist on a planet within a star&#39;s helopause. But then I wonder if even a planet could exist in such a location.

Who knows what kind of effects the tidal forces of a helopause may have on a planet&#39;s structure? Perhaps not unlike a moon inside the Roche limit of a planet.
Which is still speculated to have created the planetary rings of our gas giants.

As for a big bang wave front, If there was still a wave front created by the big bang, it would stand to reason that it would not be possible to put any kind of space ship in front of it, because there would be nothing in front of it.

Finally, I personally believe there are definitive boundries to our physical universe as we know it. However, those boundries are so far away that we either can&#39;t see them, the light images haven&#39;t yet reached us, or we don&#39;t know what to look for.

IMH Tinaa has hit the hammer square on the nail.

Maybe the edge would look like a bubble from the inside.
And if that were the case, the edge would likely be reflective in nature, perhaps even reflecting our own images back to us. And if it is doing just that it&#39;s entirely possible that we are in fact viewing multiple reflections of just a few images, much like having two mirrors facing each other, but from different angles, and different distances.

It may even be that there is only one, or perhaps very few galaxies in our universe, and all the rest we see are reflections of a much smaller universe then what we believe it to be.

However, don&#39;t call me a crackpot yet, because I didn&#39;t say &#39;this is for sure the way it is,&#39; but rather, &#39;this is a possibility of what may be, and happens to be what I personally believe&#39;. It surely warrents consideration.

AusJosh
2003-Nov-16, 04:16 AM
Of course, you could always accelerate to Warp 10 and theoretically occupy every point in space at the same time (i would naturally assume this would include the edge)....

But then again, youd need to exist inside a science fiction series first....now theres the hard part.



-Josh

StarQuestor
2003-Dec-27, 06:07 PM
So why NOT an EDGE?&#33;&#33;&#33;&#33;&#33; Nothing grates more against our intellectual skins than these concepts that can seemingly only be explained with brain exploding, mind numbing calculus or other forms of advanced math. From my own limited perspective it would seem that wether its space or matter expanding outward, that regardless of how counter intuitive it may be, regardless of how spherical our universe is where if you keep going in one direction, you have to eventually end up where you began, because I say for the universe to "expand", it has to expand INTO something&#33;&#33;&#33;&#33;&#33;&#33;&#33;&#33;&#33;&#33;&#33; Don&#39;t tell me that there is NOTHING it expands into&#33;&#33;&#33;&#33;&#33; I don&#39;t give a flaming, flying rats rear end about the circular nature of the universe&#33; I refuse to believe I live inside a megalithic video screen where we are permanantly locked inside a universe from which there is no escape when in the incredible countless trillion times a trillion years from now when there is no energy or matter left even to power a space ship that we can&#39;t somehow escape. If there is an edge, there has to be something OUTSIDE that edge...I don&#39;t think the universe is expanding inside of a concrete block. There must be some other muti or extra dimensional realm out there that all of this is expanding into. In other words, there has to be a place where an observer can look at it from the outside and watch it expanding. I realize this may be very naieve of me to think this way but you can dance around this metaphysical subject all you like with all the equations you can muster....if there is an edge, if it is expanding, then it by the very fact of its expansion must be expanding into something. Now its time for some serious open speculation on what the "something" is that the universe is expanding into. What exists outside the expanding universe? Come on people, lets not run from this subject simply because we have no way of finding out until we are dead&#33;

Sp1ke
2004-Jan-05, 10:53 AM
I think Josh&#39;s answer earlier shows why there doesn&#39;t have to be an edge. The universe&#39;s expansion is the expansion of space so there&#39;s nothing else. If "space" is what you call "everything", then this is what is expanding so there&#39;s nothing outside it so it hasn&#39;t got an edge.

Since the universe is expanding at the speed of light, there is no way to travel faster than it so it is impossible to get "outside" the universe.

It&#39;s not that the universe is expanding into a vacuum - even a vacuum is part of space.

The reason any discussion becomes counterintuitive or "brain-exploding" is that it&#39;s difficult to think about something that we can never perceive or participate in. If there isn&#39;t an edge, there is no way for a human to stand outside the universe and watch it expand. What does a four-dimensional cube look like? What about a 6-dimensional cube? 20-dimensional? There aren&#39;t any simple answers. Just saying there "has to be an edge" doesn&#39;t make it so. It&#39;s not that simple - but it&#39;s still worth persisting in trying to get your head round the concept.

What about thinking of it in two dimensions? If you imagine we&#39;re two-dimensional beings, living on a three-dimensional world. We can travel any distance on the surface without reaching an edge. If you travel far enough in one direction, you get back to where you started. If you then imagine the world is expanding at the speed of light, you can never travel fast enough to go round the world as it&#39;s growing as quick or quicker than you can move. What you can&#39;t do, as a two-dimensional being, is to leave the surface and travel in the extra dimension to get "above" the world to see it expanding.

Planetwatcher
2004-Jan-05, 04:30 PM
But everything has an end, and beginning.

Sp1ke
2004-Jan-05, 06:48 PM
A circle doesn&#39;t

StarQuestor
2004-Jan-05, 11:17 PM
An excellent reply to my tirad Sp1ke. The analogy to the two dimensional existance from a 3D point of view is very good. There are a couple holes but its still very good. From our 3D point of view, we can see the surface of a 2D surface...expanding or otherwise. If expanding, then it is obviously expanding into our 3D universe. So then, what universe or dimension is our universe expanding into.

damienpaul
2004-Jan-05, 11:20 PM
a sphere doesn&#39;t either

StarQuestor
2004-Jan-09, 03:36 AM
Gentlemen, your argument is as circular as your answers&#33;....Its a cop out. Come on, you can do better. Sphere, circle, marble or whatever only avoids the real question....what lies beyond? I imply the universe exists wether spherically or otherwise is to imply it exits inside something else. No other logic can exist in this matter...but I welcome any speculation. That is, after all, what all this is about...LOL.

Sp1ke
2004-Jan-09, 10:03 AM
Well... it all depends on what you mean by "beyond" the universe. :)

If the universe is the realm of our space and time, there is no space and time (as we define it) outside our universe. This might be where the expanding sphere analogy breaks down. Bear with me and I&#39;ll see if I can get my head round it.

If you&#39;re two-dimensional and on an expanding three-dimensional sphere, the sphere is expanding into the third dimension. So the three-D universe could be expanding into a fourth spatial dimension (forgetting about time as a fourth dimension for now). So that determines the direction of expansion. But it doesn&#39;t address what&#39;s actually outside the universe.

I guess you could say that in a hyper-universe of four spatial dimensions and one time dimension, what&#39;s outside our 3-D universe could be other universes, empty space, a sea of energy. Basically anything. But completely unobservable by us since we can never reach the edge of our universe.

Josh
2004-Jan-10, 05:19 AM
This was emailed to me by Professor Paul Davies in order to shed some light onto the question about whether there is an edge to the universe. Paul Davies is a physicist and cosmologist at The Australian Centre for Astrobiology, Macquarie University, Sydney. His latest book is How to Build a Time Machine. The above essay is based on his book The Edge of Infinity. Everyone here at Universe Today would like to thank Professor Davies for his time and answer&#33;
__________________________________________________ ____

Where is the centre of the universe?

Because other galaxies are rushing away from us, it might seems as if Earth must lie close to the centre of the universe. This is completely wrong. The pattern of expansion Hubble discovered has the special form that every cluster of galaxies moves away from every other cluster. Whichever cluster you were situated on, the pattern of motion around you would look the same. An analogy might help. Suppose by some magic our planet were to expand noticeably every day. The distance between cities would then steadily increase. Manchester would move away from London, New York would move away from Chicago and Beijing would move away from Hong Kong. Pick any two cities, and the distance between them would increase. Viewed from any particular city, all the others would seem to be retreating. But in fact no city is special. None lies at the centre of the pattern. Notice also that if the Earth expanded uniformly (rather than fast here and slow there), then a city twice as far away would retreat twice as fast: Manchester would move away from London roughly twice as fast as Birmingham. This is precisely the pattern that Hubble observed: galaxies twice as far away retreat at twice the speed. Hence we can conclude that the universe is expanding at the same rate everywhere, and no galaxy lies at the centre of the expansion.

But mustn’t there be a centre somewhere, even if we can’t spot it?

Well… It’s perfectly logical to have a truly infinite expanding universe, the same everywhere on average. Then there would be no centre and no edge at all. However, this would be indistinguishable from a universe that is merely stupendously big, with us located well away from the edge.

If it is just very big but finite, couldn’t we build a super-duper telescope and see the edge?

There is a snag with this strategy. A telescope is also a time-scope. An astronomer looking at a galaxy, say, five billion light years away sees the galaxy as it was five billion years ago, not as it is now. That’s because light travels at a finite speed (one light year per year). Physicists are convinced that the speed of light is a cosmic speed limit – nothing can go faster. So no matter how fancy our instruments, there is a limit to how far we can peer into space. This limit is set by the age of the universe. If it’s 13.7 billion years old, we can’t detect anything more than 13.7 billion light years away. So we are left wondering whether the patch of universe we see is typical of the whole – and it just goes on for ever and ever in every direction looking much the same – or whether, sooner or later, it would come to an end – or an edge – and change into something else. And if so, what? That is the basis of the recent popular “multiverse” idea: that there is an edge out there somewhere, but probably a very very long way away. From what I have written, it’s clear we will not discover the multiverse by peering yet deeper into space. Evidence for it rests on other arguments.

Why do newspapers often talk about astronomers seeing to the edge of the universe?

This is just sloppy talk. “The edge of the universe” can sometimes refer to the limit of visibility using current instruments – so not a physical edge in any sense. Or it can refer to factor I have just mentioned – the limit imposed by the finite speed of light. This isn’t an abrupt cut off. What happens is this. The farther into space astronomers look, the redder the galaxies become. At about 13 billion light years the universe is too young for proper galaxies with stars. This is the so-called cosmic Dark Age. Before that is just glowing gas, spread evenly through space, and seen by us as hugely red-shifted to a temperature of only 2.7 degrees above absolute zero. This “wall of light” lies about 380,000 light years from the “edge” defined as the limit due to the finite speed of light. This “light” edge is known technically as our particle horizon. It no more represents a true edge of the universe than a horizon on Earth represents an edge to the planet. Rather, the horizon is merely a fundamental limit of visibility. The particle horizon increases in radius with time, by one light year per year.

The above discussion is predicated on the assumption that the big bang was a true origin of time, so that nothing can reach us from the epoch before it (because, by definition, there was no “before”). That is the case with the normal, orthodox cosmological model. However, more recent models, based on eternal inflation and predicting a multiverse, treat the big bang as a local, not a global origin. In these more elaborate models, our particle horizon is no longer a true causal boundary, but it remains an observational boundary, since the big bang completely reconfigured spacetime, and reprocessed matter and energy so thoroughly that it would not be possible to look back through it to a preceding cosmic epoch. Largely this is because inflation, by its very nature, erases all information about prior epochs. So the distinction between the orthodox big bang and the more elaborate inflation/multiverse models is essentially a conceptual rather than an observational one.

Paul Davies

VanderL
2004-Jan-10, 06:52 PM
inflation, by its very nature, erases all information about prior epochs. So the distinction between the orthodox big bang and the more elaborate inflation/multiverse models is essentially a conceptual rather than an observational one.

I could be wrong about this, but doesn&#39;t this sound like admitting that the models cannot be verified?
We can&#39;t observe anything to disprove it, so it must be correct?

anewton
2004-Jan-10, 09:09 PM
Here&#39;s one for you. Many years ago National Geograghic put out an issue comparing our space advances to the ones made at the subatomic level. The jest was: every step out learned = every step in learned. The subatomic quantum physicists have come up with this "string theory" now. Could this be the shape of our universe? I&#39;ve always felt like StarQuestor on this matter. By definition alone, the univerise has no edge. Come up with a different name if you insist it is finite. Even a vaccuum is "something". Every time the scientists think they&#39;ve found the smallest thing possible, just wait a week. And what if this so called "edge" is really a door to another dimension? Maybe traveling past the speed of light takes you there, too. What shape would you give our universe then?[QUOTE]All the answers are out there, we just have to find the right questions. A B Gaston

VanderL
2004-Jan-10, 11:54 PM
I think what is happening in "advanced" science, is that people take the equations too seriously and start thinking: if the equations are ok, then it must be real. I guess Einstein started all this in a way, by doing thought experiments and proving them with math. In principle there is nothing wrong using math, but the emphasis should be on [/U]using[U] math, not the other way around. We&#39;re supposed to believe in dark matter/dark energy and a 13.7 billion year old Universe because the math tells us to. Whatever happened to common sense? We need data&#33; (not the Startrek character).
Cheers.

Josh
2004-Jan-11, 02:18 AM
VanderL, you know, I&#39;m sure, that verification (ie proof) for anything is impossible. The only verification that we can have is that something isn&#39;t right (ie falsification). And then ... hypothese have to be amended - completely (as you&#39;d like) or in part. So long as they work and survive the falsification process (hopefully without fudging ;))

VanderL
2004-Jan-11, 11:14 AM
True Josh, you basically can&#39;t prove a theory to be correct, only falsify. If a theory is devised in such a way that it cannot be falsified (like "inflation by it&#39;s very nature erases all information about prior epochs"), how can we ever know it is true? In this way, such a theory can&#39;t ever be wrong and is basically useless.
Analogous to the statement that the Sun is powered by fusion reactions. This can be more or less tested by measuring the amount of neutrino&#39;s. If we don&#39;t find enough of them (the right ones, as is the case) we should start looking for alternatives. Also you will reach a point where the theory needs so many, or such basic "adjustments", that the theory can be considered to have failed.
The problem is where do you stop investing in one model and start looking for alternatives. In my opinion for a lot of theories, we have already past the point of "credibility".
Cheers.

Josh
2004-Jan-11, 11:58 AM
No, that is a falsifiable statement. If you can test for evidence of prior epochs ... which should be possible then you can see if the theory holds. Just because the nature of things is for data to be removed in favour of something else doesn&#39;t mean that the statement is wrong. Falsification holds if the whole theory can be tested ... not one little part of it. It has to be tested in relation to the rest of the theory.

VanderL
2004-Jan-11, 01:22 PM
You mean that inflation is falsifiable? I thought we couldn&#39;t look (measure) anything past the particle horizon, so how would we show that inflation didn&#39;t happen?

Littlemews
2004-Jan-11, 08:03 PM
You mean that inflation is falsifiable?
many ( I guess its not may of them ><) scientist distinguish two facets of inflation, one as a theory of initial conditions for the hot big bang and the other as a model for the origin of structure in the Universe, but lately, they found out both of the theory are indeed falsifiable.

Josh
2004-Jan-12, 12:08 AM
...by testing other things in the theory that rely on or are pertenant to this part of the theory.

Matthew
2004-Jan-12, 03:30 AM
True Josh, you basically can&#39;t prove a theory to be correct, only falsify. If a theory is devised in such a way that it cannot be falsified (like "inflation by it&#39;s very nature erases all information about prior epochs"), how can we ever know it is true? In this way, such a theory can&#39;t ever be wrong and is basically useless.

If a statement cannot be falsified then there is a chance that the statement could be correct. Of course there is a chance that it is wrong. And it may only be un-falsifiable now, not in the future.

Josh
2004-Jan-12, 03:55 AM
The point is, Matthew, that if it isn&#39;t falsifiable then it isn&#39;t science. Plain and simple.

VanderL
2004-Jan-12, 10:17 PM
This problem of a supposition being untestable is a big problem in science today. We assume the sun is powered by nuclear fusion, we assume that redshift can be explained as the result of an expanding Universe, we assume that gravity is the only important force in the Universe, we assume that singularities/black holes really exist and we assume that there is dark matter needed to explain the observed motion of galaxies. We have to make sure that whenever a model is discussed the underlying assumptions are also clearly stated. We tend to forget what the assumptions are, and by repeating a story enough times we accept it as truth. Assume nothing.
Cheers.

scott712
2004-Jan-13, 03:47 AM
Living on The Edge
The Absence of More Space to Travel Into.

I think, more than not merely finding an end to the occurance of more stars, we might someday arrive at what appears to be a solid wall in Space. Closer examination, however, will reveal that this apparent wall is nothing more and nothing less than the end of Space itself. It will seem to be a solid barrier, made of a material, but in reality it will simply be the absence of any place further to go.

Bridh Hancock
2004-Jan-13, 06:00 AM
&#39;Edge&#39;, for me, implies a boundary; a boundary distal to a centre. On the edge of our Universe are the galaxies; all the galaxies. Very near the centre of our Universe, we have the boundary of perceivability, behind which all is a red blur; the RedBlur of the BigBang. To look back in space & time is exciting. That is our Universe&#33;? Wow&#33;&#33; To look forward, beyond this galaxy, is to look into or beyond the Edge. Bouncing back from the Edge we have detected nothing, not even with a dent in or on it. Nutrinos (nutrinoes) have been said to be coming back from there & then, having gained momentum in the great whack-back. Perhaps that idea has been knocked-back.

The BigBang was neither big, nor was there a bang. With the erruption into our time & space, surely some the super-particles moved into the centre and became the first BlackHole. As the rest of the Universe, as it spread and cooled, aggregated, exploded, irradiated, and imploded, is what we see and wonder at today. I join you in this.

Please do not obscure this document with stipple. May any artiness be outside the text box. Thank you.

Bridh Hancock

Faulkner
2004-Jan-13, 06:15 AM
Nothing is getting answered here at all&#33;

However much I respect Sir Paul Davies & thoroughly enjoy/am enlightened by his countless books & articles, I must confess I considered his statement to be very rhetorical, just repeating what we&#39;ve all read before. (I wish he had&#39;ve delved deeper for us&#33;&#33;&#33;)

The fact of the matter is, we are told CONTINUALLY that a "Big Bang" event occurred in our distant past, which was a "vacuum fluctuation" FROM nothing, INTO nothing, and that this "explosion" (or perhaps "eruption" is a better word) is EXPANDING more and more into nothing.

Doesn&#39;t make sense.

For one thing, it goes against Newton&#39;s law that "for every action there is an equal and opposite reaction". That is, as the universe pushes outwards, there MUST be something pushing back&#33;

Mr Davies&#39; likening of the universe to the surface of the Earth (which we&#39;ve all heard before) goes against the latest astronomical findings that the universe is FLAT (not "open" (saddle-shaped) nor "closed" (spherical)). In other words, parallel lines don&#39;t converge/diverge, and the angles of a triangle add up to 180 degrees.

Doesn&#39;t this recent discovery tear apart the old old picture of a universe that somehow "spherically" twists back upon itself, like a "Mobius strip"?

Doesn&#39;t it mean that perhaps the universe is in fact expanding outwards from a point-like singularity? And that, if we were to by-pass the "cosmic speed limit" by utilizing a hypothetically-feasible Alcubierrean "warp drive", we could reach an EDGE???

Also, how does the latest "findings" that the universe is a decahedronal "hall-of-mirrors" illusion in our skies relate to this???

I&#39;m confused. Seems like a lot of others here are too. I think we need a much more detailed explanation from the experts&#33;&#33;&#33; (Even the NASA "cosmology" pages, tho&#39; up-to-date with latest Hubble findings, doesn&#39;t confront these fundamental issues. We are told that the universe is FLAT, but also that it is SPHERICAL, also...etc etc...). Contradictions, contradictions&#33;

Josh
2004-Jan-13, 06:57 AM
Faulkner ... you write out your questions and I&#39;ll try and get Professor Davies to answer something a little deeper for you.

As to my humble understanding of things ... The very notion of a human trying to visualise these things is, frankly, impossible. The universe is expanding into nothing. Can you visualise nothing? No? you can visualise empty space (perhaps space is a bad word here) but not nothing. Out brains can&#39;t fathom such things. Does that mean it&#39;s not the way things are? No.

The notion that the Big Bang came from nothing isn&#39;t accurate either. The theory as far as i&#39;m aware of it is that the big bang is a direct result of a big collapse... that the universe is just one big causality loop. Therefore the universe didn&#39;t come from nothing.

As for Newton&#39;s law ... if what I said at the beginningn of this - that the universe is indeed expanding into nothing except itself - then no law is being violated.

And as to the reaching the edge in the ultra fast space ship .. still no, because there is no edge.... like the Asteroids video game analogy i made in another thread .. if you get to the "edge" you only get to the other side of the universe.

I have no idea about the rest .. but ask tell me specifically what you want me to ask Professor Davies and I&#39;m sure he&#39;ll make it clear.

Littlemews
2004-Jan-14, 02:57 AM
I have a question :
What does a curved space-time continuum do?

GOURDHEAD
2004-Jan-14, 01:07 PM
A curved space-time continuum constrains how things move in the universe. Newton assumed Euclidean space where parallel lines are always equidistant and objects in motion travelled in a straight line unless a force was applied to change their direction of travel. If the intrinsic nature of space-time is either spherical or saddle shaped, parallel lines are not everwhere equidistant and objects, free from force application, do not travel in straight lines. If space and time are each quantized, there is no continuum and objects travel, at or below the Planck distances, by disappearing in one "cell" and appearing in the adjacent "cell"...but I wouldn&#39;t bet much on it. :unsure:

anewton
2004-Jan-15, 08:33 AM
But what about when things are equidistance, and parallel; but instead of traveling ing staight lines they corkscrew around and then might even join in a circle. Something like if you put a "Slinky" ( the pliable spring-shaped toy) around your arm and raised your hand to your shoulder? Isn&#39;t that like a curved space-time continuum?

Sp1ke
2004-Jan-15, 10:48 AM
I wouldn&#39;t have thought a circular space-time continuum was impossible. That would mean if you travelled far enought in a straight line, you could end up back where you started.

Another interesting area is if space-time is simple at the macro level but curved and distorted at the quantum level. I don&#39;t fully understand it but one theory I&#39;ve heard is that in addition to the three space dimensions we are familiar with, there are around nine? other dimensions all curled up at a quantum/planck scale. That means all sorts of weird things can go on at that level but they&#39;re all smoothed out at the level we perceive things.

The one thing that seems to characterise the limits of perception is that "common sense" breaks down. Like at the quantum level, particles can exist in more than one place at once, cause and effect don&#39;t operate like normal; time might be a series of discrete points rather than a continuous flow.

Faulkner
2004-Jan-16, 12:04 AM
Josh, I&#39;d like to write out some questions for Prof Davies, but I don&#39;t know where to start&#33;? I&#39;ve got millions of questions that really twist me up inside&#33;&#33;&#33;


The universe is expanding into nothing.

This is a statement of faith, not fact. Just in the same way that calling yourself an "atheist" is just as much based on blind faith as calling yourself "christian". In place of "nothing" we should really be saying "unknown".

Imagine yourself in a spaceship, but you are OUTSIDE the universe, literally in "nothing". What do you see outside your portholes? Blind spots? It&#39;s not a silly idea, because by analogy the universe we inhabit IS our "spaceship"&#33;


the big bang is a direct result of a big collapse

This "cyclical" idea of an expanding/contracting universe (I believe) has been disproven by the fact that the Universe is flat (not closed). The official statement from NASA is that the universe is continuing to expand (in fact, accelerating).

But if the Universe is indeed "flat", does that mean geometrically flat? Well then, the old old analogy that likens the Universe to the surface of a sphere doesn&#39;t work anymore&#33; This implies a global, 360-degree curvature...so that although finite, there is no "edge" to the Universe.

So what is the truth?

Or is it a case of "we just don&#39;t know"??? (In which case, I&#39;d like to hear experts admit it&#33;&#33;&#33;)

Weaselbunny
2004-Jan-16, 01:57 PM
Originally posted by AusJosh@Nov 16 2003, 04:16 AM
Of course, you could always accelerate to Warp 10 and theoretically occupy every point in space at the same time (i would naturally assume this would include the edge)....

But then again, youd need to exist inside a science fiction series first....now theres the hard part.



-Josh
Also, if Voyager is to be believed, it would turn you into a freakish fishboy&#33;

StarQuestor
2005-Mar-20, 05:09 AM
Excellent response there by Josh with Paul Davies explanation. Its the first time I&#39;ve read anything like it that, for me at least, adequately explains some of the counterintiveness pervasive in cosmology. It really does seem that even our most astute analogies can break down at the edge of the universe and that we simply reach a point of the truly indescribable.

astromark
2005-Mar-20, 09:50 AM
This thread and the next are one in the same: No edge, No center. Infanite time and space. Faith in the fact as yet unproven. The thought that this might be finite does not registar. Its not logical. I do not exept nothing as an explanation of anything. We might have large areas of empty space. Its as near to nothing that I will exept. Am I alone?. . No.

wstevenbrown
2005-Mar-20, 11:18 AM
If there&#39;s a bright center to the Universe, this is the planet that it&#39;s farthest from.-- Luke Skywalker

John L
2005-Mar-24, 08:36 PM
Issac Asimov addressed this in the Foundation series, creating a settlement of scientists at the out edge of the galaxy so that there were only a handful of bright stars in the night sky and the dim glow of the galaxy if you lived outside the city. They settled here to avoid the chaos of the colapsing galactic empire in the hopes of founding the seed of the next empire.

Douglas Adams adressed something similar, too, with his planet Krikit, where the single star with its single planet were in the center of a dark cloud in space. To the inhabitants of this world the entire universe was their world and sun. When they finally flew out of the cloud in their first space ship and saw the galaxy, they declared war on it as it didn&#39;t fit into their universal view.

Mr Universe
2005-Jun-29, 12:36 PM
Of course you can reach the end of the universe&#33; You just need to run fast enough :blink:

Joff
2005-Jul-01, 09:44 AM
As a practical framework for the sci-fi novel, I would suggest that you use a solar system sitting directly "above" a spiral galaxy (ie. on the axis of rotation of that galaxy), about half the radius of the visible disk away from the centre with no other members of that galaxy&#39;s "local group" on the opposite side. This would give a view of a massive bright spiral in one direction and almost perfect darkness in the other.

The solar system would probably have to have been "ejected" from the parent galaxy (by some gravitational slingshot effect); maybe even built up outside the galaxy of the chance encounter of an ejected sun and an ejected planet. To lend a little credence to this possibility, there is a recently discovered star in the Milky Way with a velocity which will eventually take it out of the galaxy.