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Big Bang Abandoned In New Model of the Universe
- jdub 16y agoWas sorely tempted to write in a new headline: "Taiwanese physicist's theory threatens much-loved TV show, common understanding of the universe."
- Anon84 16y ago"Periodic" Cosmological models without a Big Bang are not new. They are easily extracted form the usual equations under certain conditions and it's one of the typical exercises you do in an intro do cosmology class. What seems to be new here is that this specific model seems to explain something that has yet to be well understood. This is a big win for this model but it can easily mean that it happens to capture part of real mechanism in that specific aspect while making unrealistic assumptions elsewhere (like the possibility of there not having been a Big Bang). It will be interesting to see how this model affects our current understanding of the universe. It might be a complete change, or just an incremental one. Odds are on the latter one but the former makes for much better blog posts... ;)
- dazzawazza 16y agoI like it when 'non standard' models get some attention. It shakes things up and maybe a eureka moment will happen.
- wlievens 16y agoUnfortunately many (most?) 'non-standard' theories are absolute crap, and it's hard for non-experts to separate signal from noise. For proof, see the perpetual energy source products that pop up every few months. (not talking about this article in particular)
- mjfisher 16y agoGood to know! If a periodic model is a potentially viable way of looking at things, could it be squared with thermodynamics? Specifically, the constant increase in total entropy.
- eru 16y agoThermodynamics just says that entropy can't decrease in a closed system. So entropy can stay constant, and in an open system everything can happen.
- flipbrad 16y agovery difficult for entropy to stay constant in a closed system. And surely universality (all-encompassing, there-is-nothing-else) means closed system? Or are we looking at open and closed in the wrong way; if the universe is periodic, could entropy decrease with order 'warping in' from a different point in time (future or past) if time happened to fold or loop over itself to feed into the back of it?
- eru 16y ago> And surely universality (all-encompassing, there-is-nothing-else) means closed system? Not necessarily. The question isn't really settled. It seems quite complicated when you get to those scales. E.g. just as an analogy, in general relativity even energy isn't really conserved. (See http://math.ucr.edu/home//baez/physics/Relativity/GR/energy_gr.html http://math.ucr.edu/home//baez/physics/Relativity/GR/energy_...) So I don't know whether we can say anything definite about entropy.
- Yzupnick 16y ago"making unrealistic assumptions elsewhere (like the possibility of there not having been a Big Bang)" I'm not sure I agree with this line. Copernicus made the "unrealistic assumption" that heavenly bodies and motions were not spherical, and Galileo made the "unrealistic assumption" that earth wasn't the center of the Earth. This type of thinking hampers scientific progress.
- JshWright 16y agoYeah, and George Smith made the "unrealistic assumption" that the moon was made of cheese, and John Doe made the "unrealistic assumption" that dogs communicate telepathically... While there are certainly a handful of "unrealistic assumptions" that have lead to scientific breakthroughs, giving credence to an idea simply because it is unrealistic is... well... unrealistic.
- evilduck 16y agoI don't know if I'd say they made unrealistic assumptions. Geocentrism failed to make accurate predictions and required a whole slew of tricks to reconcile the problems. Heliocentrism was "unrealistic" because the church disagreed with it, not because it disagreed with observations. It also took approximately 300 years for common opinion to shift from a Ptolemic universe to Heliocentrism. We're on a much shorter time scale for the Big Bang theory, and it's very well acknowledged the theory has problems.
- william42 16y agoGalileo's problem wasn't that he made an "unrealistic assumption", it was that he couldn't explain the lack of visible parallax. (It turns out the answer to that was that we didn't have good enough equipment.)
- arethuza 16y agoReminds me of a quote from James Hutton, the "father" of geology in relation to deep time: "we find no vestige of a beginning, no prospect of an end"
- brianmckenzie 16y agoWhy not just admit we don't know?
- brianmckenzie 16y agoWant to downvote more?
- Anon84 16y agoResearch always implies not knowing... If it's already known, there is no need to research it. However, it also implies wanting to know. The consequence of your comment seems to be that we should not research because we will never know and that goes against the entire body of knowledge collected by Humanity over the last 10,000 years.
- deleted 16y ago[deleted]
- brianmckenzie 16y agoThe entire body of knowledge collected by humanity over the last 10,000 years is one of war, famine, and neglect for others. We can do better.
- KoZeN 16y agoWe can do better. We already have, unfortunately ignorance will always shield you from the wealth of knowledge that exists beyond your contempt for human nature.
- nollidge 16y agoThe body of knowledge certainly _includes_ war, famine, and neglect, but it's idiotic to say that's the entirety of it.
- bvi 16y agoSo you're the kind of guy who admits he doesn't know, and then doesn't do anything about it. That's fine. But there are people who readily admit they don't know, but will do research to find a solution. You're not in that category - that's okay - but at least realize that most entrepreneurs/hackers are in the latter camp.
- TomasSedovic 16y agoI was wondering what the theory had to say about the cosmic microwave background. The answer: "we don't know yet". Still, it's great that someone tries to find new perspectives to look at. I wish them good luck in their findings.
- motters 16y agoIt sounds as if the universe is a giant pulsating amoeba.
- Maro 16y ago"Shu's idea is that time and space are not independent entities but can be converted back and forth between each other. In his formulation of the geometry of spacetime, the speed of light is simply the conversion factor between the two." This is already true in Special Relativity. This MIT TR article is so shallow it shouldn't be linked to.
- saint-loup 16y agoNo Arxiv paper should be talked about on any non-academic website.
- cromulent 16y agoFor what reason? Generally HN people are against censorship.
- Maro 16y agoIt's not censorship, it's just a social seperation of professional concerns. Non-physicists have no chance in hell to understand arxiv papers, in fact most physicists don't have a chance in hell to understand arxiv papers, even the ones from their own field. (I'm saying this as a physicist.) In this case, the MIT TR writes about a bleeding edge, unpublished paper written by a non big-name physicist that will most likely be discarded and never be talked about in 6 months. The author is from a "Institute of Statistics" and the paper was written in Word with double-space formatting. That means the author is probably not a physicist, and non-physicists have a very low chance of being able to grasp the problems with current models and propose better ones, not to mention accounting for all the astro observations coming out every day. Looking at the actual paper as somebody with a cosmology background, what he's saying is: 1. Let's take the classical Einstein equations 2. Let's see what happens if c, the speed of light, is not constant, but a function of time c(t) 3. Hm, but to not break the original equations let's also make G be a function of time G(t) such that c(t)^2/G(t) is fixed 4. Hm, but then in the derivations, where there are derivatives wrt. to time new dc/dt and dG/dt terms appear 5. and so on There is no new physics in this paper, it's just a routine derivation with a twist. The TR blogger is probably not a physicist and/or has not read it, he just pushed out some generic bullshit about space and time. There's no point in talking about this paper for non-professionals. First, professionals have to reach concensus whether this makes any sense and is compatible with observations (the former part is easier, the latter takes longer and more people). Once a result passes these tests, then it makes sense to tell people about it. If the TR wants to push out some sciency newsitem, they could for example talk about recent Higgs data from the Tevatron, which is bleeding-edge fresh but fairly uncontroversial, as it is a measurement and has gone through the Tevatron team: http://resonaances.blogspot.com/2010/07/higgs-still-at-large.html http://resonaances.blogspot.com/2010/07/higgs-still-at-large... - Reply to scott_s (for some reason I can't reply to the comment): I agree, total seperation is not good. It's not good if all the physicists involved are pure academics, because it allows for sub-optimal incentives to dominate. I believe the good model is fOR physicists with no academic incentives (positions, grants) to also take part in the discussion, eg. somebody working at Morgan Stanley or doing a startup. This model would be similar to programmers donating their time to open-source projects. (The academic counter-argument which easily wins out today is that if you're not working in the field, you don't understand the issues and don't have a say.)
- robryan 16y agoWithout to much of a technical knowledge in the area (plenty of interest just not to the paper reading level) I have been sceptical of dark matter as an undetectable equation balancer. Any good research into dark matter that I should read that puts forward a better case than balancing equations? Another problem we have, is that we have one point of observation into the unimaginably big universe. Given our limited view overfitting the data to support some model is likely.
- goodside 16y agoThe present theory concerns the elimination of dark energy, not dark matter. The existence of dark matter has been demonstrated beyond any doubt through observations of a collision between two galaxy clusters. In a nutshell, the clusters were mostly made up of high-energy plasma, and when they collided almost all of the plasma remained at the point of collision due to electromagnetic interactions between the gases. However, the dark matter in the clusters, which was previously difficult to observe independently, passed through the point of the collision (that is, through each other) as though nothing had happened. The electromagnetic interactions trapped the visible baryonic matter in one spot while the dark matter drifted off into space, allowing us to observe it independently via the effects of gravitational lensing.
- jimbokun 16y agoYou know, you could drop your comment directly into a Star Trek the Next Generation script and it would fit right in. By the time I got to the end, I was reading it in Geordie LaForge's voice in my head.
- Maro 16y agoHere's a funky explanation with buckets of water and balls, with the astro photos to go along: http://www.youtube.com/watch?v=mRtGUCLjQ3w http://www.youtube.com/watch?v=mRtGUCLjQ3w
- dedward 16y agoWait - so in a nutshell, we actually have observations that can reasonably be assumed to be dark matter causing lensing?
- timhastings 16y agoDoes this means our Big Bang generation will be mocked like the Earth-is-flat believers?
- username3 16y agohttp://en.wikipedia.org/wiki/Myth_of_the_Flat_Earth http://en.wikipedia.org/wiki/Myth_of_the_Flat_Earth The myth of the Flat Earth is the modern misconception that the prevailing cosmological view during the Middle Ages saw the Earth as flat, instead of spherical.[1][2] During the early Middle Ages, virtually all scholars maintained the spherical viewpoint first expressed by the Ancient Greeks. By the 14th century, belief in a flat earth among the educated was essentially dead. Flat-Earth models were in fact held at earlier (pre-medieval) times, before the spherical model became commonly accepted in Hellenistic astronomy.[3]
- poundy 16y agoVery interesting. I was one of those people with the misconception. How did the ancient greeks think that we were glued onto the planet? Gravity was something Newton defined? Am I having another misconception?
- joshuacc 16y agoThe prevailing model of the universe at the time was a sphere with the Earth at the middle. In this model, the term "gravity" and "weight" meant something like "the natural level of this object". Rocks had "low" weight, thus falling to the ground and fire had "high" weight, thus rising to the sky. Being composed of "earth" and "water", we stuck to the surface of the Earth because that was our natural place. A lot of this model was carried over into Medieval science, but it changed over time to adapt to new discoveries, until it finally broke around the time of Galileo & Copernicus. C.S. Lewis wrote a very interesting little work on the Medieval worldview called The Discarded Image that goes into some of this. He was writing mostly as a literary historian, but covers the scientific understanding to the extent that it informed literature. http://en.wikipedia.org/wiki/The_Discarded_Image http://en.wikipedia.org/wiki/The_Discarded_Image
- carterac 16y agoVery interesting. Reminds me of Paul Steinhardt's Ekpyrotic model that proposes our universe is the result of two colliding three-dimensional worlds: http://wwwphy.princeton.edu/~steinh/npr/ http://wwwphy.princeton.edu/~steinh/npr/ For anyone who actually read the paper, if there is no big bang and no beginning, what does this model imply about the universe 14B years ago?
- mark_l_watson 16y agoI will have to think about this theory for a while since it contradicts something that I have accepted for a long time (big bang). I'll be visiting my Dad in a few weeks, and I will enjoy getting his take on this (he is a physicist and a member of the national academy of science). I do like that it fits better with conservation of energy, and I was never comfortable with using dark matter to explain away inconsistencies between the big bang model and some observations. It will be interesting to see how much traction tis new theory gets in the next ten years or so.
- nollidge 16y agoBe sure to mention it's completely preliminary, non-peer-reviewed, and posted on arxiv.
- ajdecon 16y agoEspecially in high-energy physics and in (I think) cosmology, the community is small enough that the arXiv is basically the primary means of communication. Peer review is everyone looking at the article and talking about what they mean. Published journal articles become more of a way to "keep score" to help outsiders make hiring decisions.
- mark_l_watson 16y agoYes, my Dad and I already talked about that. He also said that indeed there are a lot of 'no-bang' models.
- ww520 16y agoYou meant Dark Energy. Dark Matter is a different matter all together. It causes pull rather than push.
- deleted 16y ago[deleted]
- ajdecon 16y agoThis is a very interesting theory. I'll admit that I find it aesthetically appealing to eliminate the cosmological constant ("dark energy"), and eliminating the big bang and big crunch doesn't bother me very much. The fit to the supernova redshift data is also impressive, though I haven't taken the time to unpack the optimization used so I'm not sure if there's overfitting going on there. The arXiv article itself also makes very interesting reading. My BS in Physics didn't get as far as the Einstein field equations so I can't follow the derivation, but the introduction and discussion are fairly easy to follow. Allowing the speed of light to vary over time has been a popular choice in a number of cosmological theories recently, but afaik the space/time/energy conversion allowed in this model is new. It's hard for me to follow exactly where the author gets the particular functional form she uses for the speed of light wrt time, but if there are any cosmologists in the room I'd love to know whether it looks "reasonable". If I had to look for problems, my gut says that the space/time/energy conversion the author suggests would predict some kind of astronomically observable result apart from an accelerating expansion. Looking for that prediction and checking it against observations would be a good step. I also noticed that in the arXiv paper, she assumes a universe with three spatial dimensions. I'm wondering if this is the case, how it will interact with string theories which assume 10+ dimensions.
- itistoday 16y agoI may get downvoted for this, but the Big Bang Theory is a great example of "scientific faith", the prevailing existence of faith amongst people claiming to be scientifically rigorous. People who make the absurd claim that it is meaningless to speak of what happened "before the Big Bang" because there was no "before." I've spoken with, and heard many professors speak of the Big Bang Theory as accepted fact, when in fact it is not, and not only that, but it has very serious, fundamental problems: - It flies in the face of logical reasoning. Something cannot come out of nothing. - The point above actually has a physical law. It's called the First Law of Thermodynamics, and the Big Bang Theory is in stark violation of it. That's not to say it's completely invalid. There could have been a Big Bang, in fact it's very likely there was, but that doesn't mean it was the "start" of anything, other than rapid expansion, or, converting into mystical terms, a reincarnation. The Universe will always be here. It has always been here. It cannot go away. It is indestructible and everlasting. The mystics understand this, and so does anyone who understands basics physics.
- yafujifide 16y agoPhysicist here. Although I am not really a "cosmologist," I have studied cosmology, and have spent a lot of time pondering the the big bang because I think it is interesting, and because so many people like you misunderstand it. The universe did not come from nothing. Consider the following two claims: * The universe has a finite age. * The universe has always existed. Both of these claims are true. It might seem that if something has always existed, it must have existed for infinitely long. No so. At every time in history, the universe has existed, even though the age is finite. Your intuition might disagree. But recognize your intuition has been developed under very peculiar circumstances on the surface of the Earth. You should be skeptical of your own intuition when studying things outside of your usual experience. In this case, human intuition says two things: * There was always something before. * There was always something 5 minutes before. In ordinary human life, both claims are true. That's what your intuition says. But for the universe as a whole, only the first claim is true, and the second claim is false. Even though it is true that there was always something "before" (for any time you give me, I can divide that time in two and give you an earlier time), it is nevertheless not true that there was always something 5 minutes before (pick 4 minutes after the big bang, and 5 minutes earlier than that is simply undefined [1]). Big Bang theory is a self-consistent, meaningful mathematical theory. It does not fly in the face of logical reasoning. Rather, it is a spectacular case-in-point of the power of logical reasoning to describe and explain the universe. Your second point is that the Big Bang disobeys the first law of thermodynamics, which is the conservation of energy. False. You are assuming there was a period of time when there was no energy, and then suddenly energy came into being. That's not what happened. The energy has always been around, for all time, and thus the first law is not violated. [1] It so happens that "negative time", or even time t=0, is equally as meaningless as Elephant Time or Verb Time. They are all undefined.
- stcredzero 16y agoI wonder what we could do with the prediction that singularities are not possible? Ob: Does the theory explain inflation? Could it be used to formulate an FTL drive.
- jmathes 16y ago"Shu's idea is that time and space are not independent entities but can be converted back and forth between each other." This is not a new idea. This was in my high school physics textbook in 1998, and it was an old textbook.
- ry0ohki 16y agoI've never accepted the big bang as an explanation for the beginning of the universe. It's an explanation of how the universe ended up in it's current state, but still doesn't explain how all that matter came to be in the first place. This new theory I can at least kind of wrap my head around, there is no beginning and no end... i don't know why but it makes more sense to me.