How big is the universe!! Is it ever expanding like the sound or it has an end to it. It's been the question since the beginning of mankind. Any one got good explanations or theories to it !? Would love to have some healthy conversation.

I can feel you bro. Sometimes this kind of crazy thoughts appears on my mind too.

We had some good discussion on this topic not a while ago. Here is the link to the thread,

http://sajha.com/sajha/html/index.cfm?threadid=111601&noofposts=17

Space is ever expanding with much faster speed than light. Speed of light is the fastest within the space only..

Hwaking666
"Space is ever expanding with faster speed than light"
Universe is expanding faster than speed of light. The whole universe lies within three dimensional space. Space itself does not have boundaries as its three dimensional extension where matter and energy interact. Observable universe has boundaries within this space but matter and energy are travelling or expanding every second on all three dimension at speed of light which results expansion faster than speed of light. Eg. here
Observable universe within a space given time - ( ** .. : *,..* )
Observable universe in all three dimension+ 1 sec time
- ( * * . . . : * , . . * )
Both ends of universe has mass/energy moving at speed of light which at the end results overall expansion rate higher than speed of light if that makes sense.
Again, on each dimensions, energy and matter travel on the speed of light when expanding and overall result looks like its faster than light because in space-time dimension sphere, energy is moving/ expanding at speed of light in all directions.
Speed of light is fastest everywhere in the universe unless external forces applied. A photon propelled from star will travel at speed of light in a space (if no external force acts on it). With zero resting mass, Photon will propagate creating electric and magnetic fields (electro-magnetic radiation) and utilizing those forces to travel through space which is fastest speed of matter/energy known to mankind.

Why is universe expanding?
One reason is Entropy/ second law of thermodynamics. The tendency of matter/energy to disperse from disorderness, unequilibirium ( unstability) to more orderness, equilibirium ( stability). A example would be a water inside a ballon, the water always have tendency to disperse but the membrane holds it in ordered form, when external force is applied, it will disperse freely within space which was its tendency. Some other exmaples are like dispersion smoke in the air, ink in the water etc. All the matter/energy was inside a membrane ( fixed boundry of universe,) which now is dispersed ( the reason being cosmic inflation), expanding, heading towards entropy which is basic property of matter/energy. The gravitational force, the force which was only holding universe together was over-run by external force ( may be dark energy, big bang explosion, cosmic inflation or unknown), the bubble with matter/ energy brusted towards higher entropy leading to expansion we see today.

There are things beyond science and its called Metaphysics. I hope you don't mind me talking about metaphysics here. Space in infinite. However, you will not understand infinity until and unless you experience infinity. True knowledge only comes through direct experience. Our forefathers already asked this question thousands of years ago and came up with the word Atma and Brahman. Atma and Brahman are same. Atma is the subtle consciousness within and we call the same Atma as Brahman because of it nature of expansiveness. However, Atma doesn't depend on Space and time for its existence. Space and time exist because of Brahman. For example, diamond doesn't intent to shine, but shining automatically happens because of its existence. Similarly, numerous universes exist because of this Atma alone. Atma is pure consciousness. Atma is undivided, immobile reality. Atma is one without a second. The drama of universe takes place in Atma. Atma is the canvas, Atma is the painter, and Atma is the color. And who is watching this painting called the Universe? Technically speaking, there is no such thing as universe of duality and universe where varieties of objects exist. When we see dream, mind itself appears as various objects, mind itself appears as the perceiver of dreams, and it is mind alone where all the drama of dreams are happening. When we wake up in the morning we realize that whatever we saw last night was fake, was unreal. How did we know that the dream we saw last night is unreal? It is because we wake up to a different finer reality which is more fascinating and more real than the dream world. However, you cannot say that the dream world was unreal. It was real for the dreamer for the time-being. Dream is not a dream but we call it dream to distinguish between our waking reality and sleeping reality. Dream is in fact waking reality in relation to dream itself because we are awake to a different reality. We only call it a dream in relation to our waking world. Consciousness is a funny thing. The moment your awareness shifts, your whole reality changes. Ordinary human beings only live through three states of consciousness: waking consciousness, dream consciousness, and deep sleep consciousness. Beyond this three states is Transcendental consciousness where universal law of Atma is revealed to you in its own glorious state. It is Sat-Chit-Ananda. It is existence, it is consciousness, and it is pure bliss. In it no duality of objects exist. It is neither existence, nor non-existence. It is immeasurable because it is infinite. Where does it exist? This question of 'where' doesn't even apply to Atma, because it doesn't depend on space. Since when does it exist? The question of 'when" also doesn't apply to Atma because it is timeless. If you see variates of objects in this universe, you are still living in waking state of consciousness which is the result of ignorance of Atma. Atma alone was, Atma alone is, and Atma alone will be. This is whole, that is whole, from whole comes the whole, when you divide whole from the whole, whole remains!

Another example that is synonymous to Universe,
A hot pot with H2O ,( *.*.)
The membranes of pot acted as force ( Gravitational force) holding H2O inside the pot.
Temperature is hot, lots of movement of particles inside in random directions because of the energy inside. Either because of internal kinetic energy of particles or external force of some kind, the pot explodes dispersing matter inside it into open space.

The mystery here still is, where the H2O/ Matter got in the pot/universe in first place. Can space/ Vaccum create matter/energy, if yes too, the universe is always grow in Mass/ energy created by space. Space is infinite, so would be mass and energy it creates. On contrary, Mass/energy can neither be created nor be destroyed ( by humans or is it universally by nature).

Unless the limits of the universe have been chartered or proved, I think it's safe to infer that the universe is infinite.

PS in my opinion.

The problem with universe is that no one knows what really happened.
Everything is based on mathematics calculation and theory which is not always correct.
To Explain how fast universe is expanding, we need to find out how it started. The widely accepted theory of start of universe is the Einsteins theory of relativity, which calculates the start of universe ad Big Bang aka singularity. But the problem with general relativity is that it explains what happened right after the Big Bang but fails to explain what happened at or before the Big Bang. So all laws of physics breaks at singularity.
It is believed, there is Big Bang and Big Crunch in the life cycle of universe. General relativity suggests that at some point, universe starts to shrink and ultimately become so dense that it collapse on itself. And becomes singularity again followed by big bang. So on current theory universe doesn't always expand.

There is new theory published few weeks back that totally rejects the concept of singularity and big bang. But predicts that the universe is there infinitely. There is no start and end.

And the concept of expanding universe is mathematically wrong. Its like saying 1= 2 = 3 ... = infinite. How can new space be created?

Ujil,
You tend to analyze physical phenomena in perspective of philosophical, spiritual, using human emotions, and humanly observations ( meaning humans are part of whole physical interractions as if we play part in speed of light, gravitation force or in any other natural forces etc). The role of humans here is just to observe and conclude intellectually what might, or is happening. You do not have to burn yourself to see or feel like how sun is burning. We have emotions, senses, intellect, understanding which matter or physical substances do not have. We are just trying observe, collect date, conclude, study the present and predict both future and past. We have no role whatsoever in this universe for the things that are acting the way they are. You do not have be a photon to observe how photon acts. Its just plain simple observation, data collection and conclusion without disturbing the system. Matter fact, we are part and product of this universe and time ( Universe, galaxies, stars, sun, planets, earth, water, minerals, DNA, Bacteria, invertebrates, vertebrates, mammals, monkeys, humans a.k.a universal evolution)
Here we are talking about physical forces, physical interractions physical phenomenas.
The universe was always there before humans evolved, before biology evolved ( biological interractions) started, even chemistry evolved ( chemical interraction). Atma, brahmans are created by humans. A dead chicken is dead as a rock. It will decay, transforms into biofuel eventually becomes a fossil fuel which is petrol. If you dig deep inside, you are just a composition of C,H,O,N, etc with intellectual mind, product of evolution which took billions of years to get here. We can fly a plane, take a robot to Mars, transplant a heart,while our close hereditary relative, Monkeys are still climbing trees.
Spiritual ?religious thoughts are end result of our intellectual brain. We were nothing before we were born and will be nothing after the death. Only us as a animal are intellectual and want meaning of life. Meaning of life is to live and we are only living because we are not dead if that makes sense.
Now lets understand infinity. A length of scale/ruler is finite. You have a starting point and ending point. Speed of light is finite. A photon starts from point A and travels to point B in one sec. You measure distance divide by time, you get the speed. The distance of earth and sun is finite. You have point A to start and Point B to finish. Both can be marked in in real-time and space. But space does not have starting or ending point. Its just there. Like numbers if you say, a finite set of numbers ( 1-100000) then its finite. But there is not limit on when or where we can start or end numbers. Likewise, Observable universe has finite space it has occupied. The space that has not been occupied by matter or energy is still space whether there is photon/matter/energy present or not. When photon reaches there then it becomes part of observable universe's space.
Infinity basically means no boundaries. You can keep on going, stop somewhere and make a boundary, but if you want to travel further there is no boundary because the extension itself does not have boundary.
Would space have boundary?
No, it is extension of three dimension where matter/energy interracts. Lets start a journey from sun, photon gets to galaxies and more galaxies, finally reach to end point of universe, as it reaches the end of observable universe, space still exists beyond that point but now photon will travel through through space beyond observable universe before. So, there was a finite universe in finite space, the very moment photon travels through that boundary, the universe expanded through space. Space was always there before the photon reached there.

The size of the observable universe is determined by the number of years since the big bang. The time when the big bang occurred was 13.789 billion years ago. Therefore the size of the observable universe is nominally 13.798 billion light years since there is not enough time for anything further away that that (and further back in time than that) to have emitted light that we can now "observe". That is what is meant by term "the observable universe".
The 13.798 billion years is the current best estimated time to the Big Bang (measured to 0.3% accuracy) and 379,000 years is the number of years after the Big Bang when the universe would have cooled off enough to become transparent. The (mostly visible light) photons from the hot plasma that filled the universe at that time have been traveling since then and have now been red-shifted down into the microwave range. This is the Cosmic Microwave Background (CMB) radiation that has been very accurately measured by the WMAP and Planck satellite.
Btw, for those who were born prior to 90s we've seen this CMB in our television sets as dark and white dots, when we didn't get any signal. CMB data is one of the most important pieces of evidence used to verify and validate our current model of the universe. This model enables us, for example, to say that the Big Bang happened 13.798 billion years ago with an uncertainty of only +/- 0.037 billion years. Two engineers from Bell Labs accidentally detected this CMB while pointing their MW detectors in the sky and got the Nobel.
If we are using only photons, we will not be able to see any further back in time (to before 379,000 years after the Big Bang) since the universe was opaque to photons before that time.

However, if we are ever able to invent and use a neutrino telescopes to measure very low energy cosmic neutrinos (which is probably impossible), then we would be able to see back to just a few minutes or seconds after the Big Bang. Finally, it is also theoretically possible to see back to roughly 10^{-30} seconds after the Big Bang if we could measure the possible gravitational waves that could have been generated at the end of the inflationary period of the Big Bang at that time ( 10^{-30} seconds ).

Will the size of the observable universe increase (or decrease) with time?

Well, if there were no dark energy creating an accelerated expansion of the universe, we would have eventually, as time went on see more and more matter in our observable universe. For example at 50 billion years after the big bang we would have seen up to 50 billion light years away and all the galaxies within that distance could be visible to us.

However, we now know that the rate of the expansion is accelerating (Thanks to Edwin Hubble!). That means that we will see less and less matter in the observable universe as time goes forward. For example, at 50 billion years after the big bang, we would be able to see out to 50 billion light years, however, there will be fewer galaxies visible than we can see right now. This is because galaxies that are currently near the edge of our 13.8 billion light year observable universe will be accelerated away from us at faster than the speed of light due to the accelerated expansion and therefore will be beyond the observable universe horizon by then. In fact, at about 2 trillion years after the big bang, the only galaxies visible in our universe will be the locally gravitationally bound group of galaxies - at most a few dozen!

Some fun facts -> Andromeda galaxy and Milky way galaxy are in collision course. Rough timeline 3-4 billion years from now ! That will be quite a view !!!!
But hey, by then our Sun will have exhausted it's fuel (hydrogen atoms to carry on nuclear fusion and form He atoms and energy ) and stopped providing light. What's up with our Surya Bhagwan !!!!
So, we humans and our imaginary GODS and associated philosophy, religion, language is so insignificant compared to the Universe and its behaviour !!~!!

@8848m.... I don't see anything that I disagree with you.

@ Ujl, It was other way, I did not agree with you.

"There are things beyond science and its called Metaphysics. I hope you don't mind me talking about metaphysics here. Space in infinite. However, you will not understand infinity until and unless you experience infinity. True knowledge only comes through direct experience. Our forefathers already asked this question thousands of years ago and came up with the word Atma and Brahman. Atma and Brahman are same. Atma is the subtle consciousness within and we call the same Atma as Brahman because of it nature of expansiveness. However, Atma doesn't depend on Space and time for its existence. Space and time exist because of Brahman. For example, diamond doesn't intent to shine, but shining automatically happens because of its existence." and it goes on.

@iled009
Great post, Like Like.
That clarifies confusion on Big Bang and expansion. Big Bang is just a theory because nobody can travel back in time and see what exactly happened. But, With these substantial evidences and data supporting the theory, universe was at one point clustered together with mass and energy.

@8848m.... Your mere observation changes the pattern how matter behaves! In such a situation, how do you even study the reality of matter whose tendencies changes by your observation? I recommend you watch this video:

FYI : Did not watch the video.
That is 100 or even more years old experiment of wave-particle duality . No offense, science has moved on. Just do research, you will find answers.

Great great observations and discussions guys. Love them. Space and time has always baffled my mind. Recently I just read that what ever we been taking for granted or else how we thought universe was created called Big Bang might not be the start really. They are saying that universe started before Big Bang. Big bang was just a collision so there was space and universe before that. Although not related to science, like Vedas say time is not constant I totally believe in it coz time slows down in space and our atomic time in earth is completely different if we take time in space so I truly believe that speed of light is the fastest in only in this universe. I am sure there are photons that travel faster than speed of light. As much as I try to go deep in study about space I feel like I am stuck by the black hole. It's too complex and we have really small amount of answes right now.

@8848m......My main point here is: "Consciousness is primary." Without consciousness, the chair, the table, the building in front of you cannot even exist for a second. Do you see anything in deep sleep state? There is no way that you can prove that objects outside have independent existent without consciousness involved. It is consciousness that gives value to everything.

Your, mine and our consciousness has nothing to do with the existence of anything around (chair, table, building, a cute girl) or in the whole universe. "We're all star dust" - Carl Sagan.
Just like the Sun, core of stars is a nuclear furnace but unlike the Sun's core, these cores manufacture heavier elements C,O,N,Fe etc.and when these stars die and go supernova all these elements are spewed into the cosmos. Hence, C in the wood of chair, table, Fe in the steel of building; N in the amino acid of that cute girl all came from some stars that went supernova million and billions years ago somewhere in cosmos. Let's make it more interesting, N in the amino acid of her one hand might have come from different star of different galaxy than of her other hand !
C,H,O,N elements from star (that went supernova) reaches earth -> simple molecules (like RNA,DNA) forms undergoes self replication -> amino acids (protein) -> single cell organisms -> multicell organisms -> .........billions years of evolutionary history....-> humans. Theory of evolution, Origin of species, how some became extinct and how some evolved over time, is better explained by Charles Darwin. Happy B'day to him.

Universe and everything within it doesn't care whether humans have conscience ! There are fundamental laws governing the Universe. Laws of Physics, call it Laws of Nature if you please.
Our conscience has only evolved since approx. 200K years ago when Homo sapiens sapiens originated and started to evolve. Compare this timeline with the age of Universe. Human species developed much larger brain (of many other things) than other primates (closest cousins chimps and gorillas). Ability to use all the sense organs to interact with the environment, and larger brain gave added advantage over other species. All of this religion, philosophy - couple of thousand years old. Btw, philosophy and religion tried to answer most of the ancient human curiosity, but with the advent of science they sound stupid (at least to me). They are not progressive ! All of the advancement in science and technology couple of hundred years old. Most recent hi-tech stuff couple of decades old.

Some fun facts - With approx. 200K years of history, humans have ruled the earth with class and style. Thanks to brain and science. This is crazy ! Dinosaurs ruled the earth for over 250 million years, they didn't do shit over that time. They didn't use science, nor they had brains like ours. Perhaps they had only Conscience !

iLED....Universal law doesn't pop out from nothing. Flower has a purple color, because it's seed contains that information. Seed is called the unmanifest reality and flower is called the manifest reality. Have you ever seen anything coming out of nothing? Space is the cause of this universe. Now, my question to you is what is the cause of this space?

Ujil,
I believe you mean consciousness equal intelligence. Is the flower purple if you see it or not? Yes, it will be purple without your presence. Some animals are colorblind, they might see red colored flower as black, does that mean that flower is red or black. The pigments inside the flowers are still the same but different animals see its color differently depending upon the senses, eyes, brain etc. But the no matter which color animal sees them, the pigments never change. We cannot see infra-red light, or ultrasounds, does that mean they are not present? No, we are not the right equipment to detect them.
Seed had biological information/pattern in it for it to become what it became. Without minerals, water, right temperature, soil acidity or whatever, it could not have grown biologically into a flowering plant and flower. There is no unmanifest reality and manifest reality as where you came definition with. It was a biological process. Same with you and me, becoming a full grown human beings from single cells of sperm and ova from our parents.

Space is always there. When no matter/energy is present, then there is empty space.
Space is occupied/wrapped around when matter is present. When you look at the sky, Its all space. Imagine, there is no air and the matter you can see is cloud. Earth, a matter that occupied the space and then there is vacuum gap between earth and cloud, where there is nothing, just empty " space". Then you go couple miles high, you will hit the clouds, which is matter again. After you pass the cloud, there is nothing, just empty "space" and then you reach moon in 239K miles traveling that distance. Then journey begin through space, some parts occupied by matter and energy, other parts nothing just dark vacuum. Space was not or does not have to be created.

Another example, A car travelling on the surface on earth. Lets imagine, for some odd reason, the whole planetary system dissipated. the car has no surface to travel upon. No forces are there acting upon it. It is just hanging on "space". The car occupies that vacuum space on its presence, if it was not there then it would be empty "space". Who created that space, nobody, its just three dimensional extension where car exists. Stars ,galaxies or any heavenly objects you see in the universe are like the car. They exists in that open space.

There is no cause of space. Space was there or will be be there whether matter/energy is present at given time or not.

@ Ronaldo7
Are there more universes, probably not. The fundamental properties of matter/energy has to be universal. From the start of time for our universe ( Big Bang), till now is what we see. What was before big bang? Irrelevant because the starting point for this universe is big bang. Before big bang, there was big big bang, then before that there bigger big bang, and before that there was biggest big bang and it goes on. So, for things to start somewhere, starting point ( time) for this universe is Big Bang.

Black holes are stars that collapsed on their own mass. On earth, if we try to jump, we cannot reach higher than 6 feet. Stone on earth cannot jump but we can. Simply,Black hole is like big earth where even photons/ anything cannot jump. The mass/density is so high, that gravitation force takes over. The space is wrapped in such a way that matter/energy falls into the hole.
If you see some videos, or read some articles/books, you will understand in more detail.