Science ABC: The Horizon Problem

Tue, Aug 19, 2008

Post filled in: Science ABC, Space

Today’s topic is a bit more complex, but requires only elementary notions to understand. It’s a problems that scientists have had many problems with, to say the least. The truth is despite the fact that there are some solutions that would partially (or even totally) explain the issue, there is no satisfactory explanation to this Big Bang related topic.

Basically, our universe appears to be uniform; look in one part of the universe, you’ll find microwave background radiation filling it, at mostly the same temperature. Look in the opposite direction, you’ll find the same thing. Nothing, so far; but we’ll get to that. You have to keep in mind that nothing travels faster than the speed of light, and this is not about just matter, it’s about physical properties and information too. So here comes the big thing.

The two edges of the Universe are 28 billion light years apart, and the universe is just 14 billion years old, so according to our understanding there is no way that heat radiation could have traveled between these horizons to even out the temperature difference. So the hot and cold spots that resulted after the Big Bang couldn’t have been evened out; but they have. This has given scientists huge head aches, and solutions are just wishful thinking.

The solution that seems to somewhat satisfy scientists is called inflation. Inflationary theory relies on the idea that just after the Big Bang, the universe expanded by a factor of 10^50 in 10^-33 seconds. So this just solves a mistery to give another one.


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Andrei is no scientist, but from an early age, he has been fascinated by science; that's why he went to college, and signed up for Geophysics. Feeling that there's a huge gap between science and average people, he rallied TP, started ZME Science, and gave it a green twist too.

Andrei has published 1495 posts on ZME Science .

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  • dags

    ootini!!!

  • http://sjerdmanczyk.wordpress.com steven

    Woooaaahhhhoooo!!!

  • http://www.samuraipanda.com Benjamin

    First off, the universe isn’t “28 billion light years” in size, we can observe a sphere around us with a diameter of about 28 billion light years. If I moved 1 billion light years away, I’d have be able to observe a bubble of the universe about 28 billion light years in diameter. Assuming the that the universe is 14 billion years old, than the 28 billion light year diameter makes sense (14 billion in one direction, 14 billion in another equals 28 billion).

    That said, the uniformity of the cosmic background radiation is a byproduct of the expanding universe along with a finite amount of energy in it. As the universe, the space around us, expands, the energy (and matter) remains constant, just getting further apart from each other, hence a uniform distribution of the cosmic background radiation.

    As for the accelerated expansion, that is the current hypothesis based on the available evidence. Remember, that what it says is that for a short duration, the universe (not the energy in it) expanded at an incredible rate, which would result in an somewhat even distribution of the cosmic background radiation. Interestingly enough, slight irregularities in the CBR might be how matter began to form.

    Ben

    Ben

  • Chris

    If we look at a galaxy 13.2 billion light years away (current record I think), we’re seeing it as it was 13.2 billion years ago. It sees a bubble of the universe ~28 BLy wide as well (we’re right on the edge of their universe!). When we take into account current inflation theory (the fact that, since those photons left that galaxy, we moved apart) the current accepted value for the width of the universe is ~ 156 BLy across!!! There are, more than likely, many times the “observable” galaxies in the universe that we will never see, since we cannot look beyond that 14 Bly horizon.

    There are hundreds of billions of stars (suns) in hundreds of billions of galaxies just in our own bubble.

    SARCASM ALERT: Yeah, we’re special, and this was all made just for us, not.

  • jn

    hey is there a site where i could read a bunch of people who dont really understand the details of what they’re talking about wax scientific about the universe?

    oh.

  • SL

    Let’s start by solving the first puzzle; spelling mystery properly. Mistery isn’t a word.

  • jj

    “hey is there a site where i could read a bunch of people who dont really understand the details of what they’re talking about wax scientific about the universe?”

    - yea, heaven forbid any layperson be interested in science… Obviously, these folks didn’t suffer through monotonous physics lectures time and time again, so they don’t have the right to “wax” about it…

    Wait, I know, let’s jump on the author about pedantic details, and then just reiterate or ignore the general gist which he got right (and which may just be all that most people give a sh*t about anyway, imagine that) Then, let’s all go complain about how media and religion are destroying a general public adoption of scientific appreciation, and why can’t everyone find it as important and significant as you do?

    hmmm… what a frustrating predicament.
    a) want public appreciation and interest in science… = more grant money
    b) don’t want anyone else within 10 feet of it who hasn’t “joined the club” by suffering through multiple degrees.

    good luck.

  • Greatroarer

    Here is my theory, we are not the only ‘Big Bang’. Our universe is defined as all the matter and energy released by the big bang, but where and why did all that matter/energy collect to that event, and how is it the only matter/energy in all of existance? I think far beyond the boundaries of our universe there is a lot, perhaps infinite, instances of matter/energy collecting and ‘Big Banging’ again and again. Our matter is flying apart too fast to pull itself back in for another big bang, but perhaps it will interact with the matter from other exploding universes. And eventually over trillion and trillions of years that interaction will collect, and create other super masses, and beyond a certain critical mass explode and create a new universe.

    Another interesting theory I read was that we are not in an expanding universe, but actually our whole universe is within the event horizon of a super massive black hole. This would actually make a tidy explanation of our appearance of an infinitely expanding universe which would actually turn out to be a collapsing universe. Also may explain the uniform background radiation. It would be radiation from outside the event horizon being spread evenly to our point of view due to our huge velocity difference and relativistic difference. This theory might also adequately explain ‘curved space’, although I have never read any theories trying to do so.

    BTW I have a degree in Physics and Mathematics, so I actually had to
    write up the math and theory involved in astrophysics and relativity as part of my degree.

    None the less, it’s always great to think of and hear of what’s crazy out in the universe.

  • colduniverse

    You assume a hot big bang. Suppose the universe was actually warming from absolute zero?

  • StopBeingRetarded

    The Big Bang never happened.

    Anyone with a tiny bit of common sense knows that.

    The whole theory is an assumption based on an assumption based on another dumbass assumption that has long since been proved incorrect.

    Redshift is not caused by the Doppler Effect.

    As soon as mainstream ‘scientists’ pull their heads out of their rectums then we can continue evolving our knowledge or reality.

    Once you realize that the Big Bang is fiction you will also realize that Entropic Heat death of the universe is also fiction.

    From there its not a far step to realize that entropy is balanced by centropy.

    If you can make it that far then you will realize that clean renewable energy is and has been a reality.

  • http://as...as stopbeingretardedisretarded

    wtf, nothing StopBeingRetarded said followed any logical sense or provided any context for his claims. You need teaching 101, chief.

  • Campbell

    I love lamp

  • cak

    This is one of the worse descriptions I have heard for the horizon problem. Why don’t I write a better one you ask, because I can’t. I can write one just as bad, but I don’t, and neither should you.

    Can you see the difference between getting people interested in Science, and propagating bad and badly written information?

  • noyb

    @StopBeingRetarded

    What the Fuck is “Centropy”?

  • farcalled

    Centropy is, I’m sorry to say, entropy with a “C”

  • http://www.digittarius.com Paul Norman

    If the universe started as a singularity, where everything in it was the same, why wouldn’t it all be the same now after growing larger? Isn’t the current universe not just a larger version of its once tiny self?

    While some “clumpiness” may have occurred, as a result of the “bang”, that later enabled star formation, the average tempature throughout should remain uniform. The arguments seem to imply that the universe expanded first and then its tempature had to somehow catch up later, as illustrated by the “hot water poured into a cold bath” metphor often used. (But then most non-math explanations of physics are pitiful.)

    I don’t see the need for inflation. All it does is make continued research cost more.

  • Another guy

    I thought i was stumbling onto another happy little explanation of physics.

    FOR GOD/SCIENCE/MY SAKE, IF YOU ARE GOING TO WRITE SOMETHING, MAKE IT CORRECT, UNDERSTANDABLE AND VOID OF IDIOTS LIKE “Stopbeingretarded” OKAY.

    Forgive the caps.

  • mobs

    what Ben said.
    whats the headaches about?

  • Jemmz

    Okay . . . getting away from all the “dumb-ass” theories and incredibly poorly written “articles,” I have something equally incredibly dumb to ask.

    I am your average lay-person, highly interested in science, but without enough brains to get my mind wrapped around all the math surrounding science. As such, once things started getting too complicated for my feeble mind to comprehend, I would tune out.

    That said, here is my own dumb-ass question:

    If matter/energy/what-have-you can be neither created nor destroyed, how did the Big Bang occur? My understanding is that there was nothing. Then there was a Big Bang (or so this theory claims, to my understanding, of course). Then there was something.

    What gives?

  • http://www.samuraipanda.com Ben

    The source of the big bang is unknown. Hypothesises are abound, from a continual expanding and contracting universe that constantly rebuilds itself (unlikely given the current observations) to “God did it”. The problem is that we can’t observe what occurred before our space-time existed when the Big Bang occurred because all our rules break down. The best we’ve been able to do is get within seconds of the Big Bang. Science will probably push that down further, but once you get to the singularity that the Big Bang originated from, all the bets are off and our observations fail. So the correct answer is “we don’t know and we may never know”.

    And no, your question is not “dumb-ass”, just a question that keep cosmologists awake at night.

    Ben

  • Kilroy

    for noyb http://en.wikipedia.org/wiki/Centropy
    thats right kids, the universe was created by a warez group.

    back on topic. Jemmz, that is true but you also have to take into account that matter and energy are the same thing. a nuclear explosion is the conversion of a small amount of “matter” into energy. and thats one way to look at the big bang, something really small and really dense, like a nuke, exploded. Some of it becames energy, some of it stayed matter, matter and energy interchange all the time, a star is a matter energy converter, it can take light elements and turn them into energy or it can cram them together and form matter, which then shoots out into space and sometimes clumps with other matter to form planets.

  • chessspy

    OK, guys,
    If the (p)universe expanded from a tiny dot of hot stuff, what space did it expand into?
    Was there an empty space already existing? if so how big is/was it?
    These theories about the early univers are all well and good, but let’s not forget that if it isn’t possible to disprove an idea, then it isn’t possible to prove it either.
    I like science, because it is always changing in order to fit the new facts as they arise, so don’t go getting all fired up because someone makes a few spooling mistooks.

  • http://www.samuraipanda.com Ben

    It’s not that the universe expanded “into” an existing space, the universe expanded as space. The material inside the universe remained constant, but the space around it expanded. What it expanded into is an unknown. It might have expanded into a higher set of dimensions, or it may have just expanded into nothing. Trying to understand it is a difficult concept because our “common sense” breaks down when it comes to “something into nothing”.

    An excellent article can be found at:
    http://www.astro.princeton.edu/~aes/AST105/Readings/misconceptionsBigBang.pdf

    Ben

  • chessspy

    Hi, Ben,
    If ‘common sense’ isn’t any help in understanding these concepts, and we have to invoke theoretical higher dimensions etc. for these ideas to work, how is that different to any other ‘snake oil’ salesman of the type that try to convince gullable people to invest in pyramid schemes and the like?
    Did an endless space or at least some sort of size dimension exist ‘before’ the universe expanded, (unless of course you want time itself to start with the big bang)?
    It is clear that all these ideas are not disprovable and if you can’t falisfy a theory, then you can’t prove it either.
    Anyone is entitled to hold as personally true whatever they like, just don’t try to peddle such ideas as ‘science’.

  • http://www.samuraipanda.com Ben

    Hi Chessspy,
    ‘Common sense’ is grounded very much in how we experience the world. It’s very different then hw the world actually is. For instance, “common sense” would tell you that a straight stick bends in a cup of water because we can see it happen, but by understanding how light refraction works, we can see our “common sense” is wrong. Part of the purpose of science is to verify common sense as true as opposed to blindly accepting what we assume to be true.
    The problem with the big bang is that all the rules as we understand them break down. But that doesn’t mean it can’t be disproved. For instance, the concepts of dimension (including time) vanish at the point of singularity. This makes it very difficult to understand what happened at the time of the big bang, or for that matter what might have occurred before the big bang. Current evidence points towards a point in the past in which all space and matter collapsed into a single point. That said, more evidence could come out that changes disprove everything and scientist would have to revise their current ideas. For instance, Einstein, in working on his equations for general relativity, could not grasp the concept of an expanding universe, despite what his equations were telling him. His “common sense” dictated that the universe was static. So he added a constant to his work to match what he understood of the universe. When Hubble produced evidence of an expanding universe, Einstein went back and realized he had been wrong, calling it he greatest blunder. He was willing to revise what he thought was truth based on changing evidence.
    But back to your original assertion, the difference between a ‘snake oil’ salesman and scientists trying to prove the big band theory is that a snake oil salesman will never back down from their product, where as a scientist will (though some are just stubborn :-).
    With the big bang, the theory is based on concrete math and experimental observations. New evidence will either fit into the theory or it won’t. If it’s the latter, then the theory has to be revisited. If the evidence is contradictory enough, the theory may be completely abandoned. So yes, big bang theory can be disproved, it just hasn’t yet. It’s not a matter of opinion, it’s a matter of evidence.
    Hope that helps.
    Ben

  • chessspy

    Hi, Ben,
    with respect, your idea of ‘common sense’ is incorect.
    When I see that a stick appears to be bent in water, my common sense would lead me to pull it out of the water to check that it was indeed bent. On seeing that it was still straight, I would plunge it back in the water to observe, or test, my first hypothesis, (that putting it in the water had caused it to bend) and then I might repeat the experiment until I had formulated a resonable answer. Perhaps I would go away puzzled but my common sense would evenually lead me to something like the correct conclusion.
    The math behind the big bang theory is just that, math to support a theory, there are several other theories,with acompaying math, (for the origin of the universe) which have a similar following, (of theorists and academics).

    How would you make an experiment to replicate the big bang?

    As you say, science at least revises it’s theories to make them a beter fit with the facts. Almost all of what was believed to be fact 300 years ago is now seen to be false, as will what we think of as fact 300 years in the future.
    I think the point I was trying to make was, that at this level of unprovable theory, there is little difference between science, religion and magic.

  • http://www.samuraipanda.com Ben

    Your “common sense” is based on your life experiences, through your senses. You know that the stick doesn’t bend because of what you’ve experienced over the years, not some inherent knowledge. Your experimentation would be based on the knowledge built on generations of social knowledge that is embedded into your mind as you grew older. Without that knowledge you would assume that the stick bent as it entered the water and unbent with you pulled it out. Just like primitive humans looking at the sky, without the pre-existing knowledge of math and the universe, you might assume that the sun revolved around the moon because that’s what your eyes told you.

    Science doesn’t need to replicate a theory to determine it’s correctness. I couldn’t replicate the big bang just like I couldn’t replicate the theories of evolution or general relativity. What I can do is look at the existing evidence to see if it fits into hypothesis, as well as make predictions that, if the hypothesis were true, would occur. Religion and magic rely on a blind acceptance of a mystery, whereas science looks to understand the mystery. That’s why science changes over time whereas magic and religion don’t (new politics aside). And who knows, in 300 years Einstein may be thought of as a loon with a bad haircut.

    Ben

  • http://www.samuraipanda.com Ben

    Your “common sense” is based on your life experiences, through your senses. You know that the stick doesn’t bend because of what you’ve experienced over the years, not some inherent knowledge. Your experimentation would be based on the knowledge built on generations of social knowledge that is imbedded into your mind as you grew older. Without that embedded knowledge you would assume that the stick bent as it entered the water and unbent with you pulled it out. Just like primitive man looking at the sky, without the pre-existing knowledge of math and the universe, you might assume that the sun revolved around the moon because that’s what your eyes told you.

    Science doesn’t need to replicate a theory to determine it’s correctness. I couldn’t replicate the big bang just like I couldn’t replicate the theories of evolution or general relativity. What I can do is look at the existing evidence to see if it fits into hypothesis, as well as make predictions that, if the hypothesis were true, would occur. Religion and magic rely on a blind acceptance of a mystery, whereas science looks to understand the mystery. That’s why science changes over time whereas magic and religion don’t (new politics aside). And who knows, in 300 years Einstein may be thought of as a loon with a bad haircut.

    Ben

  • chessspy

    Hi, Ben,
    Your trust in ‘science’ is touching, however, these very theroretical ideas are by no means quite as cut and dried as you seem to think.
    I repaeat, if an idea is not falsifiable, then it is merely a theory, often amongst many competing theories, and in the case of the ‘origins of the universe’ ones, there are many.
    I can only go back to my last unanswered question. If the universe started from a dot, what did it ‘expand into’? this idea presupposes and already existing ‘space’, and is therefore unsatisfactory.
    ‘Science’ is just people’s ideas, some good, some wrong.
    the scientists in whom you seem to put so much faith are just as bound by ‘common sense’ as we ‘lesser mortals’and on that note I hope you will let this diversion rest.

  • http://www.samuraipanda.com Ben

    It’s not a matter of trust, it’s a matter of looking at the evidence, coming up with a hypothsis, testing or using that hypothisis to make predictions, refining the hyposisis until it matches the available evidence until such point that you have an idea that gratuates to “theory”. The theory is, within the scientific community, for all intensive purposes a fact, as much as anything can be. Most laypeople have confused theory with ideas. The former are accepted explanations (big bang) for the facts that are around us (the universe appears to be expanding, the cosmic background radiation exists uniformly in all directions). An idea is more like “hey, this might explain things, lets see if it does”.

    And any theory can be falsified by showing contradictory evidence. If an astronomer points their telescope to one particular point in the sky and sees a giant turtle on which the universe rests, then the big bang theory can be tossed out. If we suddenly can show that the speed of light can be exceeded, then we can throw out Einstein’s theories. But just because we don’t witness something or can’t reproduce it doesn’t mean it didn’t happen. The court system deals with that every day when people are brought up on charges based solely on the evidence. Watch an episode of CSI (or any one of a dozen evidence shows) to see how evidence and prediction can be used to figure out a crime.

    As for prior to the big bang or what we expanded into, all I recommend listening to Astronomy Cast episode at:
    http://media.libsyn.com/media/astronomycast/AstroCast-070319.mp3
    or you can read the “misconceptions” link I posted earlier.

    Ben

  • chessspy

    Hi, ben,
    I reccomend you read this weeks new Scientist, Page 6,
    What’s happening to dark energy?
    I don’t need to see a Turtle in the sky to know that some ideas and theories are eventually proven wrong or fanciful.
    One wouldn’t normally expect to have to ‘falsify’ a theory, because a theory is just that, someones idea, which may be a resonably good fit to the facts as known at the time. (or not a very good fit as are all these unprovable ideas)
    however knowlege moves on and one needs to ‘keep up’ with the latest thinking, and a blind trust in ‘science’ is no way forward.
    I respectfully suggest you adopt a more questioning approach.

  • chessspy

    Hi, Ben,
    Thanks for that link,
    I listened to it with some amuement, it explains a lot about your trust in ‘pop’ theories.
    I have to say it is the most apalling drivel It has ever been my misfortune to hear.
    I think I have mistaken you for someone with an argument.

  • http://www.samuraipanda.com Ben

    And I’ve apparently mistaken you capable of having a civil discussion without falling back on personal attacks. I think I am done with this “discussion”.

    Ben

  • chessspy

    With respect, my ‘attack’ was not on you but the drivel in the link you posted, and the popular science you seem to accept as fact.

  • Jon Robinson

    These are very interesting discussions. It is somewhat incredible that in just a couple hundred years we have went from living in the dark to debating brane theories, singularities, and the like. These types of debates foster an endless arrary of thoughts, and questions. Thank God for the internet. I have the ability to be present for such fascinating discussions even though they occurred years ago. Thank you all for your passionate intrigue, and willingness to ask questions, and even to badger each other with your thoughts, and ideas. It is quite fun to read, and I’m glad that there are others that constantly question EVERYTHING. Surely God is pleased with our endless curiosity.

  • Ben

    I thank Vint Cerf and Bob Kahn for the Internet.

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