Amiga.org
Coffee House => Coffee House Boards => CH / Science and Technology => Topic started by: redrumloa on July 02, 2004, 03:29:00 PM
-
So does the universe go on forever, or is it a finite size? If it really ends somewhere, what is on the other end of the end? Don't say nothing, how can there be nothing? nothing is something! :-?
-
The Big Bang was like 20*10^9 years ago right? That would mean that matter has been expanding for 20 billion years, which implies there is a borderzone of absolute nothingness and where matter is present.
-
If you go to the end of the Universe, and then went across the line, then you'd be the new end of the universe. Period.
-
Greetings,
I think the universe is 'round' not 'Flat'. We may go back to where we started. The shortcuts are 'Wormholes' that cuts into the inner core of the universe.
The center could be a 'dark matter'.
Cheers,
Gizz
-
Hum,
i do like soft centres...
But i think that our Universe is curved like a Pringle, shaped like a horn, and named after a Star Trek character.
Check out the
'Picard topology' (http://mysite.wanadoo-members.co.uk/blobrana/news/darknews.htm) here.
And the minimun size of the universe is about 156 billion light years wide they figure...
See! (http://www.sciforums.com/showthread.php?t=36628&page=2&pp=20)
you there...! :-)
[BTW the age is about 14 Billion years, er, as if you didn`t know...]
-
Well, some have the theory that the existance of the universe is one string of explosion followed by implosions
with that idea, we're still in the explosion.
As far as I know, the universe is expanding at lightspeed
and has a border of plasma.
but maybe, behind that border, there are more universes? No one can know
So, the question is: is our universe alone? Is there a limit of universes? Has 'space' where these universes are a border? :lol: :crazy:
-
@Blob,
Isn't there a theory that the universe hasn't necessarily expanded at a constant speed since the big bang?
-
@PMC
Er, yea...
Space (or to give it a more technical name, 'The Universe') is big. Really Big, and there seemed to have been a `quick-slow-quick-quickening` rate of expansion according to the latest theories...
(http://www.bbc.co.uk/cult/hitchhikers/images/173/deepthought.jpg)
And because the space-time is expanding into a `void`...(er, for a better word)...then the expansion pace can be faster than light speed...it is thought that the initial expansion rate of the universe was exponential ; and it grew to like 1050 times the size of our observable universe in a second (er, or two)...
This of COURSE still restricts the things in our space-time to be constrained by light speed (er, as observed by the `fine constant` constant)
Well according to the The Guide (http://www.bbc.co.uk/cult/hitchhikers/guide/index.shtml)
-
@Blob,
Please excuse my ignorance on this!
But how could the initial rate of expansion of our infant universe be faster than the speed of light, when the physical properties of the universe itself prevent anything travelling beyond that speed?
To me it's like seeing water being poured into an enormous basin from a running tap in a stready stream, yet the water at the edges of the basin is racing outwards like a tidal wave... How could this be possible?
Or am I being a complete dunce?
-
@PMC
Space can expand faster than light. The edge of the universe which should be 14 billion ly away is around 27 billion ly away.
Consider the expansion of the universe as a sequence of phase transitions, like that which occur to water. As water cools and looses energy, it turns from vapour to water to ice. As the universe expanded and cooled, certain fundamental forces and effects 'froze out'; before these instants the universe's contents were too chaotic and high energy to make these forces felt individually. The expansion of space faster than the speed of light may have been possible during one of the earlier phases, but froze out and stopped after a certain point. It may be that the velocity of light actually changed to allow this effect to happen.
-
Hum,
i think he's aware that
Speed = distance/time
and acceleration = ( final speed - initial speed ) / time
http://www.syptech.com/applications/eq1.gif
Which all becomes meaningless when the universe is expanding into a `region` that has no `time`.
but for something in our universe (space-time) things are ,er, differant...
-
O
---------HEADLINE----------
The Universe stops expanding this week--keew siht gnidnapxe spots esrevinU ehT
-
whabang wrote:
If you go to the end of the Universe, and then went across the line, then you'd be the new end of the universe. Period.
You're assuming that our bang is the only bang that happened, what if there were millions of big bangs, all over the universe, and none of the universes has expanded far enough to come into contact with our "bangsphere?"
If this is the case, I wonder what happens when universes start expanding into each other?
-
T_Bone wrote:
If this is the case, I wonder what happens when universes start expanding into each other?
By definition, they can't. A universe is a universe; once a big bang happens there's no longer the conditions within that universe for it ever to happen again.
Besides which, the laws of physics are finely tuned and we would be able to detect the presence of other big bangs in our universe even if possible by mathematical analysis of fundamental properties.
-
Great...now my head hurts. I knew this thread would result in that....(or could it be the beer?...).
-
@Odin
Think of it as the beer bubbles expanding in the tummy. The further it expands the more ones head ache. :lol:
@blob
If the universe keeps on expanding. Detecting life ouuut ther will also be more remote.
In the end, the earth will be alone! Even if we detected life in, for example, Alpha Centari, by X years from now AC won't be around anymore cause it's furhter away now than X years ago? That's sad... :-(
Cheers,
Gizz
-
KennyR wrote:
T_Bone wrote:
If this is the case, I wonder what happens when universes start expanding into each other?
By definition, they can't. A universe is a universe; once a big bang happens there's no longer the conditions within that universe for it ever to happen again.
Besides which, the laws of physics are finely tuned and we would be able to detect the presence of other big bangs in our universe even if possible by mathematical analysis of fundamental properties.
...such as? :-)
We don't even know why the properties exist, how can we use them as tea leaves?
-
Such as: the velocity of light. This is proportional to the energy 'stored' in the vacuum of the universe in the form of transient energy. If energy was to condense again from the vacuum catastrophically enough to cause another big bang, the main result would be a drop in the speed of light. (Which would probably destroy physics as we know it, and certainly make all current life processes stop).
At all other times, the speed of light and the energy contained in the vacuum form an equilibrium which prevent the universe 'exploding' into expansion the way it did just after the big bang.
Every particle in the universe effects every other. You couldn't not notice if there was another big bang outside our sphere of possible observation, even if it was possible for there to be another one (and it ain't).
-
PMC wrote:
@Blob,
Please excuse my ignorance on this!
But how could the initial rate of expansion of our infant universe be faster than the speed of light, when the physical properties of the universe itself prevent anything travelling beyond that speed?
...
What makes you so sure that the physical properties of the universe itself prevent anything travelling beyond the speed of light?
Especially by the given background, that just last week it was in the news, that scientists succeeded in "beaming" (dematerialisation, transport, rematerialisation) single atoms over a short distance.
But aside from that I was always wondering if it really should be impossible to exceed light speed.
All I know about black holes implies that exceeding light speed must be physically possible:
If the gravitation of an black hole is really that big that even its own light can't escape from it, then it seems logical to me, that, if you're caught by the gravitation of this black hole, you will be accelerated in the direction of the centre of this gravity.
As this gravity is that strong, that even light can't escape from it, it is logical that you will be accelerated so much , that you exceed light speed before reaching the surface of this black "hole".
In my point of view (if I understood everything right) exceeding the lightspeed means that you leave the 4-dimensional space-time continuum and enter the next (fifth?) dimension.
-
Dandy wrote:
What makes you so sure that the physical properties of the universe itself prevent anything travelling beyond the speed of light? Especially by the given background, that just last week it was in the news, that scientists succeeded in "beaming" (dematerialisation, transport, rematerialisation) single atoms over a short distance. But aside from that I was always wondering if it really should be impossible to exceed light speed.
Yes, it is. For anything material, and on average, that is; it is quite easy to demonstrate that shadows can easily move faster than light. Other people have slowed light to a near standstill, and then used quite clever tricks to temporarily transmit information across the 'slow light zone' faster than the reigning speed of light in that medium.
There is a way for matter to go faster than light on average, but it involves a cheat: think of the Cerenkov-effect, better known as the blue glow surrounding any bassin-based nuclear fission reactor. Electrons moving faster than the speed of light in water cause a shockwave very similar to an airplane exceeding the speed of sound. The excess energy is radiated away in the form of the blue glow. This also means that if tachyons (hypothetical faster-than-light particles) were real, and they move through space, they would produce (very visible) Cerenkov-like shockwaves, slowing down and down and down until their speed was infinitesimally higher than c.
All I know about black holes implies that exceeding light speed must be physically possible: If the gravitation of an black hole is really that big that even its own light can't escape from it, then it seems logical to me, that, if you're caught by the gravitation of this black hole, you will be accelerated in the direction of the centre of this gravity. As this gravity is that strong, that even light can't escape from it, it is logical that you will be accelerated so much , that you exceed light speed before reaching the surface of this black "hole".
Black holes are tricky buggers. For one thing, you shouldn't think of them in terms of ordinary objects, as this is the surest way of tying your brain in knots. Black holes do not attract light, they mearly bend space to such an enormous extent that what we think of as the normal straight travel path of a photon curves inward on itself, and becomes a circle. It still moves at c, but since its travel path is no longer pointing at us, we never see it either. The point where the curvature becomes (mathematically) infinite is known as the event horizon, and nothing bigger than an atom (and probably not even something this big) will ever get there. The rest is torn to pieces by huge gravitational tidal forces. I recall that for an outsider's point of view, it would even take an infinite time for that atom to actually reach the horizon.
There's tons more to be said about black holes (you can measure their density, which, believe it or not, becomes less the more massive they are, to the point where they'd float in water or even air), but suffice to say that you will never exceed c anywhere during this final and very lethal trip of going to a black hole.
-
Dandy wrote:
What makes you so sure that the physical properties of the universe itself prevent anything travelling beyond the speed of light?
Because it would break all known physical and mathematical laws to do so.
Especially by the given background, that just last week it was in the news, that scientists succeeded in "beaming" (dematerialisation, transport, rematerialisation) single atoms over a short distance.
No, they did not. They teleported the properties of atoms over a short distance, or teleported single photons. There is no point where a whole atom was ever 'teleported'.
If the gravitation of an black hole is really that big that even its own light can't escape from it, then it seems logical to me, that, if you're caught by the gravitation of this black hole, you will be accelerated in the direction of the centre of this gravity.
As this gravity is that strong, that even light can't escape from it, it is logical that you will be accelerated so much , that you exceed light speed before reaching the surface of this black "hole".
No, that's not right. Firstly, light speed is constant and can't be accelerated or decelerated - not by gravity, not by anything. It can't escape a black hole simply because there is a point where the incident light beam is curved towards the singularity so much, instead of getting back out it just spirals inwards and is gone. Never once during this process does it change speed.
And to accelerate mass to light speed would require all of the energy in the universe - including the energy contained in the mass you're trying to accelerate. As you can see this is quite impossible. Not even a black hole can ever do this.
In my point of view (if I understood everything right) exceeding the lightspeed means that you leave the 4-dimensional space-time continuum and enter the next (fifth?) dimension.
Actually you're already present in 11 dimensions according to String Theory. Many of these hidden ('compactified') dimensions are closer to you than your clothes.
-
KennyR wrote:
Because it would break all known physical and mathematical laws to do so.
I'm sure you know that this reason in itself is not a valid one, but I cannot resist adding a little clarification for those who might not know: laws of nature are not written in stone. They are short and concise summaries of many, many observed facts, often shortened even further by borrowing the symbolism of mathematics. They are foremost human constructs. Contrary to popular belief, things are allowed (sometimes even encouraged) to break physical laws, but the person reporting such a violation had better be very sure about what he is reporting, and back up his claim with solid evidence. Needless to say, experiments which hold out under intense scrutiny almost invariably yield Nobel prizes.
Okay, enough lecturing from me, onwards with the black hole discussion.
-
Cymric wrote:
I'm sure you know that this reason in itself is not a valid one, but I cannot resist adding a little clarification for those who might not know: laws of nature are not written in stone.
I disagree. They're absolute and changeless, the maths from which the fractal pattern of the universe is drawn. Only humanity's understanding of them can possibly be 'broken'.
-
blobrana wrote:
Hum,
i think he's aware that
Speed = distance/time
and acceleration = ( final speed - initial speed ) / time
Blob kindly explained this to me in layman's terms - if I haven't thanked you already for your explaination, then thanks for your help Blob!
Beyond the expanding boundaries of our universe, there is no "time" and therefore no speed... At least that's my interpretation of it!
I have no understanding of Physics beyond GCSE level, but it doesn't stop me from being very keenly interested.
-
KennyR wrote:
Cymric wrote:
I'm sure you know that this reason in itself is not a valid one, but I cannot resist adding a little clarification for those who might not know: laws of nature are not written in stone.
I disagree. They're absolute and changeless, the maths from which the fractal pattern of the universe is drawn. Only humanity's understanding of them can possibly be 'broken'.
Maybe it already is ;-)
Actually I was just recently thinking about something you said a while ago, that anything that's even the slightest bit possible will happen eventually, as an infintesmal times infinity is one.
As I was thinking about this, I extrapolated this to every imaginable story I've ever heard, The Wizard of Oz, Willie Wonka's chocolate factory, etc and came to the conclusion that although the chances that these stories will actually happen verbatim is really really slim, they HAVE to happen eventually. Everything you can imagine has to happen eventually. A universe with two bangs (or one happening in two places) HAS to happen eventually. If you can concieve it in your mind it has to happen.
Heinlein touched upon this in "The number of the beast"