# What is the evidence for the big bang. **URL:** \ **Category:** Great Debates\ **Created:** [January 15, 2012, 12:31am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551 "2012-01-15T00:31:13Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Jon55](https://avatars.discourse-cdn.com/v4/letter/j/2bfe46/32.png) [@Jon55](https://boards.straightdope.com/u/Jon55)\ **Post date:** [January 15, 2012, 12:31am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/1 "2012-01-15T00:31:13Z")
In the year 1025 I fell asleep. I awoke in the year 2011. How and why this happened I do not know much like the orgin of the “cosmic egg” I do not expect to ever know and neither is important for this particular argument. I awoke in the grass beside some hard grey flat surface I assumed it to be some kind of lava flow (odd that it had a yellow stripe in the middle). To my astonished eyes a horseless carriage came flying by at a speed comparable to a cannonball. It had no obvious means of locamotion so I assumed that something had blew up behind it causing it to fly by me. That would be expansion. Then that night as I walked along the lava flow I could see a bright glow in the air ahead of me (city lights). So now I could see that I was right about the explosion after all. That would be a CMB. Ok thats a rather crappy anaology (it sounded better in my head) but the question is a serious one what is the difference between the assumptions I made and the assumptions in BBT? And did I miss any of the evidence to support BBT? ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [January 15, 2012, 12:51am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/2 "2012-01-15T00:51:23Z")
The most important difference is that the Big Bang theory has a great many different points of evidence that support it, not just two or three; and that evidence has been gathered by decades of systematic study, not just looking around and taking first impressions. For example, the evidence for expansion isn’t equivalent to seeing a car drive by; it’s more the equivalent of seeing hundreds, thousands of cars & other debris tumbling though the air away from a giant fireball and assuming that the fireball has something to do with the cars flying through the air. As for signs you missed; one that comes to my mind offhand is elemental abundances. There are elements that are found in nature that cannot be produced by stars; the internal processes of stars destroy them. They do however match the projected results of the Big Bang, when the whole universe was hotter and compressed. The universe is simply more consistent with a Big Bang than with anything else that scientists have thought of. It _could_ be wrong; but if it is, then the replacement theory will have to be something that produces evidence that looks an awful lot like a Big Bang to modern science. ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [January 15, 2012, 1:01am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/3 "2012-01-15T01:01:48Z")
Dr. Wikipedia to the rescue > **[Big Bang | Observational evidence](https://en.wikipedia.org/wiki/Big_Bang#Observational_evidence)** > > The earliest and most direct observational evidence of the validity of the theory are the expansion of the universe according to Hubble's law (as indicated by the redshifts of galaxies), discovery and measurement of the cosmic microwave background and the relative abundances of light elements produced by Big Bang nucleosynthesis (BBN). More recent evidence includes observations of galaxy formation and evolution, and the distribution of large-scale cosmic structures, These are sometimes called Pre... ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [January 15, 2012, 1:06am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/4 "2012-01-15T01:06:26Z")
> [@Jon55](#): > > Ok thats a rather crappy anaology (it sounded better in my head) but the question is a serious one what is the difference between the assumptions I made and the assumptions in BBT? You made assumptions that you made no attempt to test and verify. Nor did you make any predictions from your assumptions that proved to be true. The Big Bang has been tested and has predicted things that turned out to be correct. IOW, yours was a wild ass guess. The BBT is a hypothesis that has been subject to the scientific method. ---
**Author:** ![Euphonious\_Polemic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/euphonious_polemic/32/3002_2.png) [@Euphonious\_Polemic](https://boards.straightdope.com/u/Euphonious_Polemic)\ **Post date:** [January 15, 2012, 1:14am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/5 "2012-01-15T01:14:21Z")
> [@Der\_Trihs](#): > > As for signs you missed; one that comes to my mind offhand is elemental abundances. There are elements that are found in nature that cannot be produced by stars; the internal processes of stars destroy them. They do however match the projected results of the Big Bang, when the whole universe was hotter and compressed. IANAPhysicist, but I think you have some fundamentals screwed up here. Internal processes of stars do not destroy any elements. Nucleosynthesis inside stars produces heavier elements from lighter ones. Very small stars may only produce helium from hydrogen. Very large stars, larger than our sun, produce heavier elements such as carbon, oxygen, sulphur and copper and iron. Elements heavier than iron are produced by supernovas of these massive stars. The big bang did not produce these heavy elements. ---
**Author:** ![Jon55](https://avatars.discourse-cdn.com/v4/letter/j/2bfe46/32.png) [@Jon55](https://boards.straightdope.com/u/Jon55)\ **Post date:** [January 15, 2012, 1:18am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/6 "2012-01-15T01:18:21Z")
> [@Der\_Trihs](#): > > The most important difference is that the Big Bang theory has a great many different points of evidence that support it, not just two or three; and that evidence has been gathered by decades of systematic study, not just looking around and taking first impressions. For example, the evidence for expansion isn’t equivalent to seeing a car drive by; it’s more the equivalent of seeing hundreds, thousands of cars & other debris tumbling though the air away from a giant fireball and assuming that the fireball has something to do with the cars flying through the air. True my analogy is woefully inadequate but would you agree that the only real evidence for expansion is that everything seems to be flying apart at the moment so the assumption is that it was always that way. This smells of false logic to me. > [@Der\_Trihs](#): > > As for signs you missed; one that comes to my mind offhand is elemental abundances. There are elements that are found in nature that cannot be produced by stars; the internal processes of stars destroy them. They do however match the projected results of the Big Bang, when the whole universe was hotter and compressed.. Ah yes that is the third major “proof” of the big bang Der Trihs. I do think there are only three though but it is early maybe I will be corrected on that. But I do not think of predictions that are later observed are actually proof. Consider this famous case: “Later, similar calculations on supposed perturbations of the orbits of Uranus and Neptune suggested the presence of yet another planet beyond the orbit of Neptune. Eventually, in 1930, a new planet Pluto was discovered, but we now know that the calculations in this case were also in error because of an incorrect assumption about the mass of the new planet. It is now believed that the supposed deviations in the orbits of Neptune and Uranus were errors in measurement because the actual properties of Pluto would not have accounted for the supposed perturbations. Thus, the discovery of Pluto was a kind of accident.” [http://csep10.phys.utk.edu/astr161/lect/history/perturbations.html](http://csep10.phys.utk.edu/astr161/lect/history/perturbations.html) > [@Der\_Trihs](#): > > The universe is simply more consistent with a Big Bang than with anything else that scientists have thought of. It _could_ be wrong; but if it is, then the replacement theory will have to be something that produces evidence that looks an awful lot like a Big Bang to modern science. Well I do understand that for progress to be made assumptions have to be made. I just think in this particular theory the assumptions are large and numerous. ---
**Author:** ![Jon55](https://avatars.discourse-cdn.com/v4/letter/j/2bfe46/32.png) [@Jon55](https://boards.straightdope.com/u/Jon55)\ **Post date:** [January 15, 2012, 1:24am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/7 "2012-01-15T01:24:40Z")
> [@Wesley\_Clark](#): > > Dr. Wikipedia to the rescue > > [Big Bang - Wikipedia](http://en.wikipedia.org/wiki/Big_Bang#Observational_evidence) From the website above: “After some controversy, the age of Universe as estimated from the Hubble expansion and the CMB is now in good agreement with (i.e., slightly larger than) the ages of the oldest stars, both as measured by applying the theory of stellar evolution to globular clusters and through radiometric dating of individual Population II stars.” I take this to mean if our predictions dosent match the evidence we just jiggle the numbers a little bit. ---
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [January 15, 2012, 1:27am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/8 "2012-01-15T01:27:23Z")
[Start with this thread.](http://boards.straightdope.com/sdmb/showthread.php?t=638150) ---
**Author:** ![Jon55](https://avatars.discourse-cdn.com/v4/letter/j/2bfe46/32.png) [@Jon55](https://boards.straightdope.com/u/Jon55)\ **Post date:** [January 15, 2012, 1:38am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/9 "2012-01-15T01:38:27Z")
> [@Euphonious\_Polemic](#): > > IANAPhysicist, but I think you have some fundamentals screwed up here. > > Internal processes of stars do not destroy any elements. Nucleosynthesis inside stars produces heavier elements from lighter ones. Very small stars may only produce helium from hydrogen. Very large stars, larger than our sun, produce heavier elements such as carbon, oxygen, sulphur and copper and iron. > > Elements heavier than iron are produced by supernovas of these massive stars. > > The big bang did not produce these heavy elements. "One of the major pieces of evidence for the Big Bang theory is consistent observations showing that, as one examines older and older objects, the abundance of most heavy elements becomes smaller and smaller, asymptoting to zero. By contrast, the abundance of helium goes to a non-zero limiting value. The measurements show consistently that the abundance of helium, even in very old objects, is still around 25% of the total mass of “normal” matter. And that corresponds nicely to the value which the BBT predicts for the production of He during primordial nucleosynthesis. For more details, see Olive 1995 or Izotov 1997. Also look at the plot below, comparing the prediction of the BBT to that of the Steady State model (data taken from Turck-Chieze 2004, plot provided by Ned Wright). " [http://www.talkorigins.org/faqs/astronomy/bigbang.html](http://www.talkorigins.org/faqs/astronomy/bigbang.html) (About a quarter down the page under the heading “c) Abundances of light elements”) Is this better and would it be just as valid to assume the elements were created in these ratios? ---
**Author:** ![Jon55](https://avatars.discourse-cdn.com/v4/letter/j/2bfe46/32.png) [@Jon55](https://boards.straightdope.com/u/Jon55)\ **Post date:** [January 15, 2012, 1:49am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/10 "2012-01-15T01:49:36Z")
> [@Marley23](#): > > [Start with this thread.](http://boards.straightdope.com/sdmb/showthread.php?t=638150) I read that thread and found the OP’s starting premise to be preposterous. Plus the subject matter ranges from Tim Tebow to the definition of theorize…whoops that was you wasnt it \ I was hoping to keep this thread a little more focused. Would you prefer me to post my arguments on that page? ---
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [January 15, 2012, 1:54am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/11 "2012-01-15T01:54:10Z")
> [@Jon55](#): > > Would you prefer me to post my arguments on that page? You may as well post in your own thread - I was just pointing out that a lot of this was already discussed just a few days ago. > [@The Big Bang's Trinity?](https://boards.straightdope.com/t/the-big-bangs-trinity/609198/2): > > We can see from Dopper shifts that some galaxies are moving away from us, and we can see that galaxies that are farther away are moving away faster. […] the first piece of support for that theory is the cosmic microwave background. The Doppler shifting of light is also a significant piece of evidence. > [@The Big Bang's Trinity?](https://boards.straightdope.com/t/the-big-bangs-trinity/609198/3): > > Erm, no, not according to my understanding. Cosmic inflation (aka big bang) was determined by empirical measurement, via red shifting among other things. > [@The Big Bang's Trinity?](https://boards.straightdope.com/t/the-big-bangs-trinity/609198/44): > > It is an observed fact–not a postulate or a hypothesis or an article of faith or anything like that–that when we measure the distance to far-away galaxies, and then look at the light they emit, we see that they have a red shift proportional to their distance. We know from experiments on Earth (and basic physics) that a red shift can be caused by something receding from the observer. > > That _is_ the evidence, to start with. Later on, they detected radio waves from space–in all directions, any direction you look–called the cosmic background radiation–which was _predicted_ to exist, before anyone actually detected it. It’s considered a very good sign for a hypothesis if it _predicts_ that evidence will be found, and then that evidence is, in fact, found. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [January 15, 2012, 1:58am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/12 "2012-01-15T01:58:30Z")
> [@Euphonious\_Polemic](#): > > IANAPhysicist, but I think you have some fundamentals screwed up here. > > Internal processes of stars do not destroy any elements. Actually they do. Beryllium for example [is destroyed in stars](http://en.wikipedia.org/wiki/Beryllium#Isotopes_and_nucleosynthesis), and the available beryllium is produced by cosmic rays. All the heat, pressure and radiation inside stars breaks up some elements even as it produces others. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [January 15, 2012, 2:06am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/13 "2012-01-15T02:06:10Z")
> [@Jon55](#): > > True my analogy is woefully inadequate but would you agree that the only real evidence for expansion is that everything seems to be flying apart at the moment so the assumption is that it was always that way. This smells of false logic to me. Expansion is not the same thing as the Big Bang. That is one explanation for the perceived expansion, the other (the steady state theory) is that space gets created everywhere. That hypothesis makes predictions also, which were not confirmed, whereas those of the Big Bang theory (as modified) were. Anyone is welcome to come up with an alternative theory, but it had better fit the observations and make some predictions which vary from the Big Bang theory. Now, let’s talk about the case in the OP. The blowing up theory will predict that this is a one time event, and that you wouldn’t see other projectiles. It also assumes that if the projectile was impelled by a single event, it should be slowing down due to friction. Seeing other cars moving at the same speed at regular intervals, and measuring their speed and seeing that they sometimes even accelerate falsifies your initial hypothesis. ---
**Author:** ![Jon55](https://avatars.discourse-cdn.com/v4/letter/j/2bfe46/32.png) [@Jon55](https://boards.straightdope.com/u/Jon55)\ **Post date:** [January 15, 2012, 2:19am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/14 "2012-01-15T02:19:24Z")
Marley Thank you. I agree that there is hard evidence (redshift) to support the idea that everything is moving away from us however when it was discovered that everything is moving away at a far faster rate than BBT could account for dark energy was just made up out of thin air. AFAIK the only evidence of dark energy is the speed at which things are flying apart. As for Meatros point "Erm, no, not according to my understanding. Cosmic inflation (aka big bang) was determined by empirical measurement, via red shifting among other things. " I dont think there is any such evidence perhaps you could provide a link. I spent a few minutes searching for a repuatble source that would say yea or nay and did not find one. I will search some more later in the meantime there is this. “Although inflation has many attractive features, it is not yet a proven theory because many of the details still do not work out right in realistic calculations without making assumptions that are poorly justified. Probably most cosmologists today believe inflation to be correct at least in its outlines, but further investigation will be required to establish whether this is indeed so.” [http://csep10.phys.utk.edu/astr162/lect/cosmology/inflation.html](http://csep10.phys.utk.edu/astr162/lect/cosmology/inflation.html) MEBuckner Yes the CMB is a uniform “glow” that was predicted. The observation does not tell us anything about where the “glow” came from. ---
**Author:** ![Candyman74](https://avatars.discourse-cdn.com/v4/letter/c/ad7895/32.png) [@Candyman74](https://boards.straightdope.com/u/Candyman74)\ **Post date:** [January 15, 2012, 2:20am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/15 "2012-01-15T02:20:09Z")
Ugh. These “I don’t understand this scientific theory, but I know it’s wrong” threads are starting to depress me. I really must stop reading them. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [January 15, 2012, 2:22am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/16 "2012-01-15T02:22:00Z")
> [@Voyager](#): > > Now, let’s talk about the case in the OP. The blowing up theory will predict that this is a one time event, and that you wouldn’t see other projectiles. It also assumes that if the projectile was impelled by a single event, it should be slowing down due to friction. Seeing other cars moving at the same speed at regular intervals, and measuring their speed and seeing that they sometimes even accelerate falsifies your initial hypothesis. The cars also lack a uniform overall direction. The Big Bang not only explains why faraway galaxies are moving relative to us; it explains why all the ones too far away to be affected by our gravity are going _away_ from us. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [January 15, 2012, 2:24am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/17 "2012-01-15T02:24:07Z")
I’ve mused occasionally on how I might explain modern technology to a fairly bright time traveler from the late Enlightenment (I’m pretty sure, for example, someone like Ben Franklin could readily grasp the internal combustion engine if broken down into five or six intermediate steps), but explaining cosmology to someone who’s never even seen gunpowder in action… yikes… ---
**Author:** ![Candyman74](https://avatars.discourse-cdn.com/v4/letter/c/ad7895/32.png) [@Candyman74](https://boards.straightdope.com/u/Candyman74)\ **Post date:** [January 15, 2012, 2:27am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/18 "2012-01-15T02:27:02Z")
> [@Jon55](#): > > when it was discovered that everything is moving away at a far faster rate than BBT could account for dark energy was just made up out of thin air. > AFAIK the only evidence of dark energy is the speed at which things are flying apart. Oh, FFS. Nobody invented dark energy. It’s a friggin’ placeholder name which became popular because it sounded cool. It is nothing more than a label, frequently used, to say “there’s an effect we don’t yet understand taking place”. We needed a word, so we didn’t have to telepathically communicate a concept to each other, so we used a whole bunch of them and the media pretty much settled on “dark energy”. ---
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [January 15, 2012, 2:32am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/19 "2012-01-15T02:32:20Z")
> [@Jon55](#): > > I agree that there is hard evidence (redshift) to support the idea that everything is moving away from us however when it was discovered that everything is moving away at a far faster rate than BBT could account for dark energy was just made up out of thin air. No, it wasn’t. This was discussed in the thread I linked to: > [@The Big Bang's Trinity?](https://boards.straightdope.com/t/the-big-bangs-trinity/609198/9): > > [Here](http://www.theregister.co.uk/2012/01/10/astronomers_largest_map_dark_matter/) are some “pictures” of dark matter. You can detect it by its effect on light coming from sources behind it, through gravitational lensing. > IIRC, it was hypothesized because the mass of visible galaxies was not large enough to account for the lensing observed. > > Inflation made predictions about the lumpiness of the cosmic background radiation - predictions which were confirmed. > Dark energy is required to explain the observed expansion of the universe, but I’m not sure it has been observed as such, unlike the other two. I’m not sure it has made it to theory status yet, but I could be wrong. > Now could the OP explain why he thinks these things are “beliefs” aside from not knowing much about cosmology? There are plenty of books and popular articles on this, including a full book on gravitational lensing. > [@](#): > > Yes the CMB is a uniform “glow” that was predicted. The observation does not tell us anything about where the “glow” came from. It’s a strong indication (although not the only one) that the universe began in a smaller and more uniform state. ---
**Author:** ![Jon55](https://avatars.discourse-cdn.com/v4/letter/j/2bfe46/32.png) [@Jon55](https://boards.straightdope.com/u/Jon55)\ **Post date:** [January 15, 2012, 2:36am UTC](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551/20 "2012-01-15T02:36:38Z")
> [@Voyager](#): > > Expansion is not the same thing as the Big Bang. That is one explanation for the perceived expansion, the other (the steady state theory) is that space gets created everywhere. That hypothesis makes predictions also, which were not confirmed, whereas those of the Big Bang theory (as modified) were. > Anyone is welcome to come up with an alternative theory, but it had better fit the observations and make some predictions which vary from the Big Bang theory.. Yep Fred Hoyle I believe. IIRC the theory works quite well with quantam physics and you dont have the inflation problem. Not sure why it was discarded (by most) perhaps it was Hubbles redshift? I know I am not the best with terminology please bear with me. > [@Voyager](#): > > Now, let’s talk about the case in the OP. The blowing up theory will predict that this is a one time event, and that you wouldn’t see other projectiles. It also assumes that if the projectile was impelled by a single event, it should be slowing down due to friction. Seeing other cars moving at the same speed at regular intervals, and measuring their speed and seeing that they sometimes even accelerate falsifies your initial hypothesis. Yes I knew my analogy was bad but I am seeing more and more how bad it really was…I hope it was at least humorous. [Next page](https://boards.straightdope.com/t/what-is-the-evidence-for-the-big-bang/609551.md?page=2)