Your Biggest Cosmic Questions, Answered (Part 1)

By Corey S. Powell | May 1, 2013 3:36 pm

Fifteen years ago, a small cabal of researchers took some of the most firmly held notions about how the universe works and turned them on their head. Until then, everyone was sure that the expanding universe was born in an explosive Big Bang and had been slowing down ever since, dragged by the gravitational pull of untold billions of galaxies. But in fact the expansion is speeding up. Everyone was sure that matter was what dominated the overall behavior of the universe. But in fact it seems that “dark energy,” not matter, is running the show. Whoops.

Stephen's Quintet

In Stephan’s Quintet, the ruddy galaxies are 8 times as far away as the bluish one at upper left. Astronomer deduce distances by measuring how light is affected by the expansion of the universe. (Credit: NASA, ESA and the Hubble SM4 ERO Team)

The May cover story in DISCOVER magazine (Confronting the Dark by Zeeya Merali) chronicles that game-changing discovery, and lays out the latest thinking about what dark energy is and how it affects the fate of the universe. As soon as the article was published, DISCOVER’s inbox began to fill with letters from curious readers wanting to know more. Here I will address sweeping, big-picture questions about cosmology. I’ll consider more specific queries about dark energy and dark matter in a following post.

Before I dive in, an important pieces of context. The answers I give here are not my own. They are distilled from the dedicated efforts of astronomers and physicists around the world, working with the greatest telescopes and instruments ever built. There is a lot we still do not know about how the universe began and how it will end. Some widely held ideas will, very likely, again be overturned. But the past century of research has yielded an amazingly detailed understanding about the overall structure and workings of the universe. OK then, on to the questions!

I have seen maps of the universe, but I never saw where it started. Is there some way we could plot the direction of all the galaxies to reverse engineer the starting point?  –Roger D.

This question, and several other similar ones we received, gets at one of the most confounding yet fundamental ideas in modern cosmology. The Big Bang was not an explosion in space—it was an explosion of space. Put another way, the Big Bang took place everywhere at once because space itself emerged at the same time as matter and energy. There was no outside space that the universe expanded into (at least not in the familiar three-dimensional sense), and there is no one location we can point to that is the place where the Big Bang began.

Wherever you are sitting now, you can think of that as the center of the Big Bang. It is as accurate as picking any other location. Sorry, but that’s the real answer.

From our perspective, galaxies appear to be flying away in all directions. Observers elsewhere in the universe would see the exact same thing. There’s nothing special about our spot, because every location in a uniformly expanding universe appears to be at the center of the expansion. Plotting the direction of galaxies cannot reverse engineer the starting point; again, it will only lead right back to where you are.

You might wonder, how can galaxies all be flying through space in such neat formation? The answer again requires discarding the notion of “space” as a fixed, immutable thing. In the overall expansion of the universe, galaxies are not flying at tremendous speeds through space; space itself is expanding, increasing the total scale of the universe.

What is the shape of the universe? Is it a hollow sphere? The balloon analogy seems to suggest it is, but it can’t be that simple. –Howard L.

The balloon analogy is a visual tool that that cosmologists often use to help explain the expansion of the universe. Imagine you are sitting on the surface of an enormous balloon that is marked with dots. If the balloon is inflated, the dots appear to move away from your location in all directions. The same is true for any other observer at any other location on the balloon. Furthermore, the speed at which the dots move away is proportional to their distance. Imagine the balloon doubles in size after a minute. Dots that were an inch away are now two inches away; dots that were two inches away are now four inches away (ie, they have moved twice as far); and so on.

Cosmic timeline

Another way to look at the shape of the universe: a plot of the changing radius of the visible part of universe over time. By far the most extreme expansion happened in the first fraction of a second–and this diagram is very much not to scale. (Credit: NASA/WMAP Science Team)

The problem with the balloon analogy is that it is just an analogy. On a local scale the surface of the balloon is essentially a two-dimensional membrane, but the universe is a three-dimensional space. The balloon has a geometric center in three dimensions, whereas the universe does not. “The interior of the balloon is analogous to the 4th dimension,” explains Brian Schmidt, who shared the Nobel prize for the discovery of the accelerating universe. In that sense, he argues, you really can think of the universe as a higher-dimensional sphere. I don’t know about you, but I that pretty hard to visualize.

Cosmologists do talk about the overall “shape” of space in the universe. This is a way of describing what would happen to a beam of light traveling an extremely long distance through space: Would it curve or move in a straight line? (The shape of the universe is influenced by its overall density.) A widely accepted cosmological model called “inflation,” developed in the 1980s, predicted that the universe should be almost perfectly flat. At the time, there was no way to tell, but now we know that the prediction was correct: By studying microwave radiation emitted shortly after the Big Bang, NASA’s WMAP satellite has found that the universe is flat to within a 0.4% margin of error.

How about that. The world is flat after all.

What existed 10 minutes before the Big Bang? What caused the Big Bang to occur? How many other Big Bang universes are there? – Joseph T.

The simplest and most honest answer to this question is, “nobody knows.”

Oh, but plenty of people are wiling to theorize. There are many ideas out there in the scientific literature. In the 1920s and 1930s a number of scientists, including Albert Einstein, considered the possibility of an eternal, cyclic universe that expands, contracts, and rebounds over and over. Those original models failed because they violated the second law of thermodynamics; essentially, the universe would keep running down instead of resetting. But the idea of endless rebirth is so appealing that it keeps coming back.

One form is the ekpyrotic cosmology co-developed by Paul Steinhardt at Princeton University. In this model, the Big Bang was sparked by the collision of two “branes”—three dimensional worlds moving through higher-dimensional space. Picture two crinkled pieces of paper banging into each other and you have the right idea, within the limits of visualization. When the branes hit, our universe was born and the two branes moved apart. After a trillion years or so they will collide again, triggering a new Big Bang and a new universe, and then again and again. According to Steinhardt’s calculations, the cycle could keep going essentially forever without violating thermodynamics.

Another type of eternal cosmological model emerges from the theory of inflation—the same one that predicted that the universe is flat. Cosmologists Andre Linde and Alan Guth, two of the creators of inflation theory, realized that this model could allow not just a single Big Bang but endless Big Bangs, each giving rise to new universes. In this model of eternal inflation, our universe is just one of a multitude—a multiverse—which could be infinite in extent and duration. Each universe is born from a quantum fluctuation in an energy field, which rapidly buds off and expands into a new universe. The inflation field can be thought of as the trigger that made the Big Bang go bang. Guth once called this “the ultimate free lunch.”

And things get weirder. Each universe could have its own laws of physics, meaning that some would be almost exactly like ours and some would be completely different. String theory (which attempts to build a single set of rules to explain all particles and forces) predicts there could be 10500 different types of universes. For now this is pure speculation, however.

The underlying theory of inflation, on the other hand, accurately matches many of the observed properties of the universe, and it has received impressive empirical support. Inflation predicts a specific pattern in the cosmic microwave background, the radiation left over from the Big Bang. The WMAP and Planck satellites have observed just such a pattern. That does not prove that inflation is correct, but it sure does make the theory look more credible.

If the Big Bang initially expanded the universe faster light, doesn’t that violate Einstein’s belief that nothing can exceed the speed of light? –Rick B.

If inflationary model of cosmology is correct, the universe expanded faster than light—much, much faster than light—in the first 10-30 second of existence. At first blush that sure seems like a violation of Einstein’s special theory of relativity, which states that nothing can go faster than light. More specifically, though, special relativity states that no object with mass can match (or exceed) the speed of light. In the early universe, objects were not moving through space faster than light; space itself was moving faster than light, which does not violate Einstein at all.

Sounds like cheating, doesn’t it? But this concept is completely true both to the letter and the spirit of Einstein’s theory. Special relativity explains the behavior of light and moving objects, and accounts for why the laws of physics look the same to all observers. The hyper-expansion of space would not affect the local laws of physics, and any objects receding faster than light would be fundamentally unobservable and hence irrelevant.

Once again, the key is dispensing with the idea of objects moving through space and getting used to the idea that space itself can stretch. That is also essential to understanding the current thinking about dark energy and the accelerating expansion of the universe.

The author refers to the redshift related stretching of light as arising from the Doppler Effect, but this is not true. It is from space stretching which is distinctly different from the elongation of wavelength from the Doppler Effect. –Tom M.

The writer is correct. As distant galaxies move away from Earth, their light gets stretched and reddened. The resulting “redshift” is how Edwin Hubble (drawing on data from unsung astronomer Vesto Slipher) deduced the apparent expansion of the universe in 1929. Many scientists—including Hubble himself—have attributed that reddening to the Doppler effect, even though that explanation is not technically accurate.

The Doppler effect causes waves to pile up if they are moving toward you and to stretch out if they are moving away. The classic example is the siren of a fire engine, which shifts to a higher note as the engine approaches you and suddenly shifts to a lower note as it passes by and begins to recede. Astronomers observe Doppler shifts all the time, measuring how various objects are moving toward or away from their telescopes. This is one of the primary ways that scientists have identified planets around other stars.

But as I keep saying (and please bear with me), the expansion of the universe is due to an expansion of space itself, not to the motion of galaxies through space. As light waves move through expanding space, they themselves get expanded and shifted to the red. (The balloon analogy is useful again: Think what would happen if you drew a wave on the balloon and then blew it up.) The result is essentially equivalent to a Doppler shift, but the root cause is very different. For this reason, the redshifts of distant galaxies are properly known as cosmological redshifts. A tip of the hat to Tom M. for catching a subtle but important error.

Follow me on Twitter: @coreyspowell

  • http://www.facebook.com/tony.morgan.169067 Tony Morgan

    If I draw a wave on a balloon, then blow it up, the wave not only increases in wavelength, but also in amplitude. For sound waves, that would mean it becomes lower pitched and louder. Are you saying light from distance stars are redder… and brighter?

    • http://www.facebook.com/people/Jeffrey-A-Jones/1286772008 Jeffrey A Jones

      Have you listened to what passes as music nowadays? I think that ear splitting cacophony is proof of your contention.

  • yvessaintdid

    Inflation theory suggests that the universe WOULD be like the surface of an inflating balloon, but you say here that it isn’t. So what gives? Also, the accelerating expansion theory didn’t take into account that the further away the galaxy, the closer in time it was to the inflationary “bomp”.

    • http://profiles.google.com/ackiener Andrew Kiener

      As the article says, the balloon is an imperfect analogy. It doesn’t represent all the dimensions in which space is expanding, because there’s no way to visualize that.

      Not sure what your second point is getting at, but it’s unlikely that the people who developed the theory just forgot something that basic.

    • Iain Park

      Point 2. There is no way for us to predict where the center of the universe is. All we can see is 14 billion lights ago in any direction. Does that make us the center? NO!
      Jump in a big lake (with scuba gear) and go down to the limit. Now look around. is this the entire universe? NO! But it is all you can observe. Same problem with astronomy. There are observational limits witch have nothing to do with the absolute limits involved with the universe.

  • John M Beatrice

    If the universe is due to an expansion of space itself, what is on the other side of space? Nothing? How could all that weight be held up? I prefer to believe space is infinite and the galaxies and planets, etc are expanding within it. Makes more sense to me.

    • http://profiles.google.com/ackiener Andrew Kiener

      “held up” above what? If there’s nothing outside space, there’s nowhere for it to fall. Messes with the head, but we can’t ignore the data.

      • John M Beatrice

        That blows my mind completely, that there’s nothing outside of space. How can it expand into nothing? Put a balloon in a small box and try to inflate it – it won’t work. But if you inflate it outside the box, it will expand. Therefore the universe has to expand into something – what I call “dark energy”. And in my mind it can’t expand into “dark energy” unless the “dark energy” is infinite – always been there, no beginning, no end. As human beings we can’t understand infinite, but “dark energy” has to be (infinite) in order to support the mass and weight of the universe as it is expanding.

        • http://www.facebook.com/people/Jeffrey-A-Jones/1286772008 Jeffrey A Jones

          If one were intellectually honest, the Christian Bible has an answer for that. In essence, the physical universe is a figment of the Creator’s imagination, the spirit world is the only true existence. It contends the physical was a special, temporary creation for the purpose of developing beings to add to the Creator’s family and will be destroyed when the plan is completed. The old ‘design requires a designer’, and ‘a law requires a law giver’ scientific (and practical) principles.

          But of course that is fantasy. We all know the universe (or better 10^500 universes) sprang into existence spontaneously. a much more scientifically plausible explanation.

          • John M Beatrice

            Thanks for reminding me that 10^500 universes sprang into existence spontaneously. That actual helps me understand it much better and perhaps supports my theory that “dark energy” is the glue that holds it all together. I am not formally trained in science or cosmology or math and therefore do not know what 10^500 is other than it is a very big number, probably pretty close to infinite.

            As far as religion and God I don’t prescribe to any of that. Religion and the existence of God or gods was from the minds of early human beings trying to explain their existence and what happens after they die. Religion has been the root of all evil on earth. I hope there are some other universes among the 10^500 that have beings that have a better thought process.

          • waterfall_lover

            John, I appreciate the “spirit” of your comments in your 2nd paragraph. It is beyond the reason of the “Christian” mind to understand that we all sprang from the same singularity (the Big Bang source, to the best of our reasoning). Therefore, no RELIGION has domain over any other . . . for we are of one source = we are all One (origin).

          • http://www.facebook.com/jso.rsa.3 Jso Rsa

            So in other words John, you feel that your unprovable belief or “faith” in the nature of the universe including any supreme being(s) – in other words, YOUR religion and its particular dogma – is inherently superior to the unprovable beliefs of those with whom you have a difference of opinion. Got it.

          • John M Beatrice

            I am non-religious and I do not believe in a personal God. As far as my belief that space is infinite, yes I believe I am correct. Not superior, but correct.

          • Iain Park

            If one were at all honest they would not post religious myth as fact.

        • facefault

          “Put a balloon in a small box and try to inflate it – it won’t work. But if you inflate it outside the box, it will expand.”
          You’re thinking of a box as nothing. A box isn’t analogous to nothing, because the universe’s boundaries aren’t fixed.

          Think of inflating a balloon in a vacuum.

        • Iain Park

          common misconception, WE experience expansion into something. Expansion into nothing? Ha. It doesn’t exist outside of us, just like nothing exists outside of a black hole to any denizens inside it.

    • Iain Park

      How many turtles support this theory?

    • Fred Tross

      And if it were not so where does the border of a universe end and that of a neighboring universe commence. I think it is pointless talking about multiverses unless such questions can be answered.Let’s face it, it is much easier to believe that space is infinite than to think of there being a wall beyond which the umteenth universe cannot expand…and by what law would such expansion be forbidden anyway.

      • John M Beatrice

        It is not that it is easier, it is more logical to believe that space was an infinite vacuum before the Big Bang occurred. Remember, infinite means no beginning, no end, it was always there. No human brain on this earth will ever be able to explain this phenomenon. They can only explain what is residing in this vacuum.

    • Emkay

      Yes, space is infinitely large and I say the people who posit that the universe is flat are nuts!…everything I can see is round and has gravity that works to hold objects in place, though not perfectly…There is a center of the earth, moon, sun etc..etc.. its only logical the universe is also round and has, or had, a center.. it is hard to comprehend the largeness of infinity, as well as the inverse, or infinite smallness.. we keep dividing atoms into particles and neutrino, and quarks etc etc.. but we will never be able to divide a particle and get nothing, will we…just as we will never know where the end of the universe is… oh, the dark matter/energy stuff is nuts too….

      • John M Beatrice

        Finally, someone who agrees with me. They said the earth was flat once, but we know how that turned out. Reconsider the dark matter/energy stuff, however. If space is infinite, which we know it is, then it could very well be made up of dark matter/energy which consists of all the ingredients and sub particles to produce the Big Bang which resulted in 10^500 universes being born. What blows my mind is the perfect mathematical order of the universe and life itself. There’s only one conclusion I can make, and that is that the “formula” for life is also infinite. It was always there, had no beginning, will have no end. Each universe may have 1 or more planets that meet the requirements to produce life as we know it. Our universe had at least 1 that we know of – Earth.

  • Steve Schuller

    If space itself is expanding, are all physical objects expanding as well? Including you and me?

    • Valjean1

      The stretching of space, we are told, is only at large scales and not small, like us. Yet, we are also told, it stretches the frequencies of light, which is very small scale. Some things seem to be s “stretch”.

      • http://www.facebook.com/steve.zara Steve Zara

        The stretching of space is at all scales, but it doesn’t pull us apart because our bodies are held together by physical forces which are vastly stronger than the force that results from the stretch. You are a little taller than you would be if space were not expanding, but you aren’t ripped apart.

        • Valjean1

          Posing the question elsewhere that if space is stretching how come the distance between us and our neighbor galaxy is getting less rather than more the answer I was given was that the stretching is at large scales only and space is not stretching at smaller scales, such as between galaxies or within atoms.

          • Iain Park

            There is also motion, and the nearest galaxy is coming towards us. don’t forget gravity is also a player and it is always on and always attractive. Or in other words, Earth sucks.

        • Emkay

          getting ripped is fun…

    • http://www.facebook.com/people/Jeffrey-A-Jones/1286772008 Jeffrey A Jones

      According to my bathroom scales, I think you have hit on the next world changing scientific discovery!

    • Emkay

      my expansion started around age 43…

  • Valjean1

    If it’s stretching space that is moving all away from each other they would all retain the existing relationship to each other. Yet it’s said some entities move towards or away from each other…which says there is movement that is not related to the stretching alone. Are there two motions going on at the same time…one with the flow of the stretch and the other moving within that stretch? Like one moving with a wave and the other contrary to the direction of the wave?

    • Iain Park

      Expansion of space is the all things move away, Gravity is always on so some things move closer together etc.

      • Valjean1

        So, some things move closer to one another because gravity between them is stronger than the expansion, other things move away from each other because expansion is the stronger and even more other things move away from each other at different rates due to different gravity strength reflecting different distances. And all this at every scale from tiny to cosmos wide.

  • Valjean1

    Einstein likened acceleration to gravity, even though one squashes and the other stretches. Might it be that the stretch is accelerating ever faster, if it is, but that gravity, while not reducing the rate of stretching, is reducing the rate of the acceleration of the stretching? And the acceleration is still from the initial creation of motion, aka: energy?

    • http://profiles.google.com/ackiener Andrew Kiener

      If I understand inflationary theory correctly, the whole point of it is that gravity is NOT reducing the rate of acceleration. If it were, the acceleration would eventually go to zero, then contraction would start.

      • Valjean1

        It would not reduce the rate of acceleration but the INCREASE in the rate of acceleration. It’s two different things…rate of acceleration and increase in rate of acceleration. Accelerating from 0 to 60 in 10 seconds and accelerating from 0 to 60 in progressively fewer seconds…Maybe?

        • Iain Park

          Nope. The question is “Will the rate of inflation overwhelm the capability of gravity to bring it back?”

    • http://www.facebook.com/people/Colin-William-Den-Ronden/1375054437 Colin William Den Ronden

      Don’t think of accelleration as change in speed, as that happens only in some circumstances. Gravity is accelleration but without change in speed (unless you are falling from a plane etc.). If you are in orbit the accelleration is towards the centre. If you ride upwards in an elevator the initial accelleration adds to the gravitational, increasing your weight momentarily. Accelleration is a force that acts on you, when you change speed your inertia allows you to feel that force. Over small ranges your atomic forces pull the atoms back together even though space is expanding. Just imagine resting, rather than sticking, a small piece of paper on the balloon. The paper still holds together as a small piece while the balloon expands.

      • Iain Park

        Colin you are dead wrong. Acceleration is vector change. The earth travels around the sun at a known speed. One year per orbit. So all that solar gravitational energy is doing what? Keeping us in orbit. We would speed off in whatever direction without it,but gravity accelerates us in a different direction every single moment of every single instance of every single day. We are constantly accelerating in a circle.

        Try it with your car, do laps without adding gas.
        Or in other words a body in motion will travel in a straight line without an outside force accelerating it.

        • Emkay

          “every single moment of every single instance”….
          please define ‘moment & ‘instance..

      • Valjean1

        The paper stays the same size while the balloon expands yet, the peaks and valleys of light energy frequencies increases, the red shift, with the expanding space? Expanding space expands things at large and tiny scales but not intermediate scales?

    • Iain Park

      meaningless post dude.

      • Valjean1

        Many of today’s accepted “facts” were considered meaningless when suggested…including Einstein’s posits.

      • Emkay

        ditto….

  • Joe W

    It would also seem that some of the inherent difficulty with conceptualizing this is that we are inherently wedded to three dimensional space as we perceive it. Given higher dimensional conceptualization, consider our perceived world as a 2 dimensional plane, a three dimensional object (e.g. cube) that interacts with that plane could be perceived as a singular point, to a line, or even more complex shape (e.g. diamond, square, rectangle) .
    Further that object could interact with other 2 dimensional spaces
    simultaneously. It is possible that space as we perceive it, is merely the three dimensional manifestation of higher dimensional interaction, to include the expansion of our perceived space without violating other laws of higher dimesional physics.

    • Iain Park

      Many dimensions have been speculated and mathematically proven. However we are 4 dimensional beings, we also perceive time. But to try to wrap your brain around the fifth dimension … mind you they had some good songs back in the day.

      • Emkay

        the dawning of the age of ‘Aquarius’…

    • Emkay

      dimesional physics would not allow it, Joe…

  • http://www.facebook.com/Kneeclovesu Denise Gonzalez

    This article would be called a Research article.

    • waterfall_lover

      I wondered if any female would eventually post a comment in this discussion.
      Why do you use the term “Research” for this synopsis of our present understanding (as currently accepted by the widest group)? Perhaps a more appropriate term is that this is the “collaborative best theory” of all that is as is now understood.

      • Emkay

        easy for you to say…..

  • http://www.facebook.com/people/Jeffrey-A-Jones/1286772008 Jeffrey A Jones

    The passage quoted below is pretty well a synopsis that answers all those questions, including why ‘intellectuals’ reject it’s message. Of course it must be rejected as myth, no way is there a higher intelligence than human theoretical scientists, but it sure stands the test of time and is much more intellectually appealing to an ignorant proletariat like me than 10^500 different parallel universes! The latter seems a little desperate don’t you think?

    “In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things were made through Him, and without Him nothing was made that was made. In Him was life, and the life was the light of men. And the light shines in the darkness, and the darkness did not comprehend it.”

    • Ian W

      You’re making the common mistake of theists in assuming that scripture has any authority. It does not. Scripture was created by human beings. So your argument isn’t that some god is wiser and smarter than modern humans, but that scientifically illiterate tribes-people were smarter and wiser than modern scientists. That’s a ridiculously naive claim to stake.

      • http://www.facebook.com/people/Mark-Steven-Zuelke/1447566498 Mark Steven Zuelke

        And you make the common (and mortal) mistake of denying God.
        The beginning of wisdom is to fear the Lord.

        • Iain Park

          Faith over science is what has the Saudi Wahabbists killing people all over the world in the name of Islam. Care to join them?

          • Emkay

            add up all the people killed in every war ever fought by any people(s) since recorded history, multiply by ten and you will have the number of people that have been killed in the name of “God”…..

        • waterfall_lover

          If a higher power (God or “the Lord”) is all-loving, then it is illogical that one need fear this higher power. Respect is a better concept – - just as a child has respect and admiration for a parent.
          It is also illogical that a higher power would in any way feel threatened by its creation.

        • Fred Tross

          Mark , it should come as no surprise that intellectual scientists would rather swallow fish hooks than lean towards God or a Supreme Being as an explanation for what is unknown and what will probably remain unknown throughout the ions. Most commonly, creeds contain the passage : “Creator of all things, seen and unseen” The human race is just too proud to admit that some things will always and forever remain beyond their comprehension.

          • Frank Schoeman

            ‘the ions”? a deliberate reduction to the atomic level, or a typo? C’mon the original was ÆONs, no iota in sight

          • Fred Tross

            typo! fixed. Thanks Frank

      • John M Beatrice

        Agree with you 100%

    • http://www.facebook.com/people/Colin-William-Den-Ronden/1375054437 Colin William Den Ronden

      The word Verb is derived from Word. Verb is a word of doing, action, which thus incorporates Time. So He set the universe into action in other words. The Omega and Alpha, the beginning and the end.

      • Iain Park

        LOL> The Bible says so, so it must be true. Prove it dude.

    • yvessaintdid

      There is no greater intelligence in the universe than that of our best theoretical physicists! JK.

    • Frank Schoeman

      So, you quote: [John 1:1] something written by hearsay a generation or so after the WORD’s crucifixion. Yea, the WORD is Jesus.

      From my KING JAMES:(Genesis; Chapter 1: “In the beginning God created the heaven and the earth. And the earth was without form and void; and darkness was upon the face of the deep.”

      1)An extant earth without “form” and “void”? It, “earth”, is written as ‘something’, but can ‘something’ be “without form” and (“void”=EMPTY). Sounds like “the vacuum” to me?
      2)If “darkness was upon the face of the deep.” What, given “heaven” and an earth “without form and void”, explains “the deep”. Anybody who claims belief in ‘the God of Abraham’ while acknowledging that “the Bible” is NOT the literal truth, has my respect to that pesron’s right to BELIEVE. Just DO NOT try to to convince me that “the Bible” is the “literal Word of God.

  • Knight E. Knight

    On the balloon analogy, I find it helpful to think of the inside of the balloon as the past, and the outside as the future, and the surface of the balloon as the present.

    • matt

      I like that. So assuming the balloon analogy is valid, the “center” of the universe is not a physical place in 3 dimensions but rather would be t=0, i.e., the center of the balloon. The balloon’s surface (representing the basic 3 dimensions of the universe) has no natural center becomes it’s warped around another dimension known as time.

      But wait… what it the universe is more like a single hemisphere of the balloon?? Then wouldn’t that hemisphere have a natural center on the surface, even though every dot is moving away from every other dot as the hemisphere expands outward? This hemispheric universe would still have a t=0 center, but it would also have a 3-dimensional physical center. The problem is still that an observer on any given dot would have no a way of figuring out which dot was the center since the edges of the hemisphere are not observable and thus the shape of the entire universe is not measurable.

      • Emkay

        damn right!….lol..

  • Ian W

    I think you’re missing Roger D’s point. He’s not talking about the surface of a balloon, but about the air in the ballon. If he saw you inflating a balloon which was, say, an eight-inch sphere, and he asked you where the center of the inflated sphere was, would you point to the skin and say “Anywhere on here”? I hope not!
    If the balloon is not a good analogy, then astronomers need to quit using it, but if it is a good analogy, then the air in the balloon has a center. In the same way, if the universe expanded to where it is today from a singularity or something like that, then the location of that singularity was the center, and there ought to be a physical place in this universe which corresponds to where it was when it started its expansion. Otherwise, it makes no sense at all to say that the universe is expanding equally in all directions.
    The only way that everywhere can be the center of the universe is if the universe is infinite, and we’re being told that it isn’t. So if the universe is some 90 billion light years across (or whatever the figure is) then 45 billion light years in is the center.
    If we lay people are asking bad quesitons, then the fault isn’t with us, it’s with the cosmologists for failing to do a better job of explaining adequately what the universe is really like, so we know enough to ask better questions!

    • UnhappyVoter

      I think that rather than use the balloon analogy, a better one is “loaf of bread” analogy. In that example, two raisins within an unbaked loaf of bread dough will move away from each other as the bread bakes, not because they are “moving”, but because the dough itself is expanding. In this same way, items in the macro scale of the universe appear to be moving apart because space itself is expanding. I believe that this analogy provides a better visualization of the expansion than the two dimensional surface of a balloon.

      • yvessaintdid

        Movement resulting from the expansion of space is still movement. It isn’t just apparent movement.

        • Frank Schoeman

          Quibble, quibble.

    • Iain Park

      But we can only see a small portion of the balloon. 14 billion lights in any direction. All indications are that somebody on the edge of our detection range would have the same observation. So don’t think of it as a balloon but as a multi-balloon where all points of observation are the center.

  • matt

    So I always thought of the state of the universe at the big bang as being super dense. But going with the balloon analogy, and if it was the fabric of space itself that was expanding–not the atoms within it–would a theoretical inside observer in that initial universe be able to detect a difference between it and the state of the universe today? Would they feel any more dense than “normal”? Do universe-level differences even affect things on the inside of it? Just curious, since I don’t know, and haven’t read through the comments yet.

    • Valjean1

      It seems to me…There is more space than matter inside an atom we are told. If space is stretching ( as opposed to expanding, there’s a difference ) then it is stretching within the atom. Space is space, throughout the universe. If it stretched differently in different places it would be very lumpy universe messing with calculations assuming regularity…it would seem.

    • Iain Park

      As space expands, it drags the atoms with it! So your one inch ruler still measures the same inch over the same surface. What does change is the strong and weak forces that exist within atoms on Plank distances.

      • Emkay

        it certainly does not…and is strong and weak sort of like yes and no?…most planks were around 10 to 14 feet…

    • Emkay

      comments will not help you, and Einstein is gone….

  • The Logic Party

    Considering the balloon analogy, and the citation in the article that the universe is flat to 0.04%: Is it possible that the portion of the universe we can see appears flat because it’s tiny compared to the entire universe? I know the balloon explanation is an analogy, but is this possible? Can anyone answer definitively? Also, of the known stars and galaxies, are they accelerating away from each other ‘along’ the known universe plane?

    • Iain Park

      We have no conception of the ‘entire universe’ because our observations are limited to the local neighbourhood of ‘fourteen light years’ or so. We cannot see anything beyond that because of the Hubble limit (look it up it’s interesting). Gravity can give us hints of things beyond our observable limit, BUT it will all be pure speculation. The universe may be infinite, and it may not. It may have the same laws of physics all across, or it may not.

      There is just no way for us to know at this time.

      • yvessaintdid

        I think you forgot to type “billion” after the “fourteen”. JS.

      • John M Beatrice

        They’ll never be able to actually prove it because they will never be able to Hubble or graft an infinite entity. It may be speculation to a cosmologist, but an infinite space is the only logical conclusion.

    • Emkay

      true, almost, of course, most definitely, and not without permission, infinite largeness has to be accompanied by infinite smallness…

  • Jim

    If space is expanding, then, what is it expanding into? If space expands into “non-space,” then, what is non-space like?

    • Iain Park

      Space doesn’t expand into anything, that is just our 3 dimensional thinking. It just gets bigger. As an analogy think of a bunch of perfect cubes all pressed together. Sides don’t have to match up. Now double all cube sides instantly. Space gets bigger but 1 mile is still one mile To those inside. What is outside? Nobody knows we are inside a singularity, we think.

      • Jim

        Lain, would “singularity” be a fantasy world where existence can be without “non-existence;” and, space can exist without “non-space”? If so, then, we can’t even know that space is expanding…

        • Emkay

          if pigs had hip pockets, they could carry knives and not have to be afraid of snakes….lol..

    • John M Beatrice

      Space is not expanding. What is expanding is our universe. Space is infinite so no matter how much our universe expands, there will always be enough space to contain it.

      • Jeff hampton

        As mentioned in my earlier post you, along with the scientists, have no clue. We are incapable as humans to understand how or when the universe was created or if it always existed. LIKE TRYING TO TEACH A BEETLE PHYSICS!!!!!!

  • John

    Is their any consensus over whether the Universe is infinite or finite?

    Does the Big Bang theory assume the Universe is finite?

    Are there any predictions as to when the Universe will run out of Hydrogen and all stars will go dark?

    Is there a formula that shows how far a beam of light will travel given the power that generated it? Or does it go on forever?

    Do photons from light ever cease to exist?

    What is the relationship between dark matter or energy and atoms?

    • Iain Park

      All we can directly observe is about 14 Billion light years of photons coming in our direction (time as distance). These photons (because of expansion of space) have traveled about 42 billion of today’s light years (as a distance). Because photons (light) travels at the speed of light, time (duration) does not exist for them (Einsteins theory of relativity) so they do not decay. So your little, tiny, watch battery photon showing you the time will last just as long as another generated by a supernova! It just might not have the same amount of energy.
      Dark matter is still unknown, so no relationship exists that you or I could understand. Same with dark energy. They are called dark because we as yet have no way of observing them /it.
      Atoms are pretty well understood that is why we have all this wonderful chemistry going on. Not that we can’t have more or better.

      • yvessaintdid

        Light ceases to exist when it’s absorbed by something in the material universe, such as a photographic film.

        • Frank Schoeman

          For photo-film: A very small portion of that light is reflected, the rest is converted to the chemical ‘energy’ needed to make the ‘photo’ image, and ‘heat’. The ‘heat’ is on a smaller scale than the lack of change in ambient temperature, say 70 F when a stick of butter melts when a convex lens (aka “Burning Glass -en.wikipedia.org/wiki/Burning_glass‎)
          concentrates available sunlight on a small area of the butter.
          BTW the melting spot grows because the ‘melting’ of the butter at the focal point itself releases ‘latent’ heat. Enough of high-school science, Look it up!

    • Fred Tross

      The Law of Conservation of Energy holds that energy can neither be created nor destroyed. It follows then that has always existed in some form or another but forever a constant in the system (say the Universe). If photons cease to exist, then their energy must be accounted for in other forms (say dark energy) and conversely the process may well occur in reverse in which case light energy would be spawned from dark energy. If there is an imbalance of the two then the residual exists in energy forms eg. heat, radiant or other unknown forms which are relevant to the conversion of light to dark or light to dark as the case may be.

  • http://www.facebook.com/tim.toth.94 Tim Toth

    Question I have pondered – If the Big Bang resulted from a singularity of infinite density exploding/expanding, and nothing can escape a singularity, how could the enegy and elemental particles escape this giant singularity to create the Universe?

    • Iain Park

      Because we are inside the singularity.

    • yvessaintdid

      Perhaps the entire history of the Universe has taken place inside a black hole.

  • Emkay

    yeah, gee thanks Tom.M…that little tidbit just helped me solve my Rubiks Cube…

  • http://twitter.com/teen_femdom Bossy Girls Femdom

    If the universe has a shape will it have an edge? If I somehow “tunnel” through space and go 50 billion light years from Earth will I be at the edge or do I need one or more jumps? It is not possible to have an infinite number of stars. Infinity in mathematics is often an indication of impossibility. Infinite space is hard to visualize. Think about a sphere that has no surface because the surface is at infinity. My question

    How large is the Universe?

    What created the rules of physics that made the Universe possible to come to existence?

    • John M Beatrice

      It was never created, it was always there. There was no beginning and there will be no end. The only thing created was the universe in which we live from the physics that made it possible. But the rules of existence and the formula for life have always been there within the vacuum of space which is infinite. The vacuum of space had no beginning and will have no end. Our universe had a beginning and will have an end as will others within this infinite vacuum of space.

      • http://www.facebook.com/holdcraftm Michael Holdcraft

        John,
        What you describe is explained in the Bible, it’s GOD! Scientists search for Dark Matter, the stuff controlling our Universe – it’s God! He controls everything, He is what he is. He is the “I am” of everything, but that is too much of an over simplification for “scientific vain man” to accept.

        • John M Beatrice

          I know it is “God” but there is no “he” in “God”. (no “she” either) “God” is not personal. “God” is just a word made up by ancient man to explain our existence. It was later attached to religion which has been the root of all evil on this earth. Space is infinite meaning it has always been there without a beginning, therefore a god could not have created it. Our Universe was created, but it was created because it matched the formula of physics and mathematics to make it happen. Life appeared on Earth because the planet Earth matched the requirements to support the formula for life. It blows ones mind and it is a lot easier to believe in a religion, but unfortunately religion is just man made. I respect your belief, please respect mine.

  • eman Hachem

    just come to see every new on cinema at
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  • Bob

    The beginning of the Universe? Wake up! There never was a beginning, and there never will be an end. Humanity seems to need to bring everything together in a “beginning” and “end” scenario. why?

    • John M Beatrice

      Because the human mind cannot comprehend it. Every thing we know has a beginning and an end.

  • Jeff hampton

    What I find truly upsetting about this article is scientist knew over 10+ years ago that the Big Bang theory was incorrect but waited a long time to notify the none scientific community in an attempt to correct their mistakes (Dark Matter).
    The theories today are developed by highly intelligent scientists in a completely different realm of thinking that I am capable of. However, as far as I am from their intellect they are even further away from understanding even 1% of how the universe works.

    My theory!!!!!

  • http://www.facebook.com/holdcraftm Michael Holdcraft

    This is a great article because it actually tells us how much we really don’t know about our existence and our Universe! How much we don’t know about everything. We can only measure a small portion of what we can see and the great majority of what exists is unseen (i.e. Dark Matter??? – just a label). I’m glad we have scientists who are willing to admit this fact. Theories are just that, and all of them are based on just a little of the information that exists. Each time we discover what we consider “new information” the theories change or we create a new competing one.

  • Keith Salvas

    Light travels through space at the speed of light relative to your frame of reference. The Doppler red-shift is due to motion through space itself. Sound moves through water at 3700 ft/sec. If I’m on a train with a long tube of water I will measure the speed of sound at 3700 ft/sc without regard to the speed of the train. That’s my frame of reference. If I could step off the train I would measure the speed of sound plus the speed of the train. However, I can’t step off space to measure the speed of light at faster than the speed of light. There are 2 dimensions to the expansion of the universe: The one we can see as evidenced by the Doppler shift, and the one we can’t see because our existence, right down to our perception of it, expands with it.

  • tini

    Well i think the balloon analogy is misleading, at least it was in my case. It makes one think that the universe is curved. Well if anyone could tell me what is the actual shape of universe it would be realy appreciated. I cant believe it’s flat cuz it has been giving so much surprises that flat seems too intuitive and simple

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Out There

Notes from the far edge of space, astronomy, and physics.

About Corey S. Powell

Corey S. Powell is DISCOVER's Editor at Large and former Editor in Chief. Previously he has sat on the board of editors of Scientific American, taught science journalism at NYU, and been fired from NASA. Corey is the author of "20 Ways the World Could End," one of the first doomsday manuals, and "God in the Equation," an examination of the spiritual impulse in modern cosmology. He lives in Brooklyn, under nearly starless skies.

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