I was watching one of those TLC-type shows that discusses the origins and phenomena of space. One of the things that has always intrigued me is the idea of the Singularity. That everything in the Universe was concentrated at one, singular point, hanging out somewhere in what I guess would be called at the edge of pre-space, since “space” technically isn’t supposed to exist.
One of the statements made in the show that caused this OP (I’ve thought of it before, but I always forgot to post) was that the “Singularity” was the size of an atom. What atom? Helium? Meitnerium (AN-109)? Whatever they are using as their baseline, this is as believable to me as the idea that a 900 year old Noah built a boat and put every animal in the world on that boat with an opposite sex partner. I’m just not buying it.
Is this just cosmological hyperbole, or do folks actually believe this? I know there is a ton of unused space in the construct of an atom, specifically between the nucleus and the electrons in orbit around the nucleus. But enough area to smoosh everything in the universe into that area? C’mon now.
This “theory” makes things nice and neat for the Big Bang Theory, (one singularity, then Kaplooey! Instant universe! Instant everything!)
However, I’m starting to have some problems with the Big Bang Theory as well.
If the Big Bang actually happened, shouldn’t we be able to wind everything back to see where that singularity was located (theoretically, I mean?). The one point where EVERYTHING expanded from?
If the Big Bang actually occurred from a singular point, wouldn’t each and every galaxy be moving away from us and every other galaxy? Or does that only hold true if our vantage point is from the singularity itself? From what I understand now, there are galaxies that are both red shifted and blue shifted from our vantage point, indicating some are headed away from us, and some toward us.
What is the prevailing theory on HOW the singularity could be created? I know at one time it was thought that the universe went under a Bang/Crunch cycle every so often, with the forces of gravity ultimately pulling everything back to the place it began. However, this seems implausible at best. Gravity is indeed a powerful force, but if each galaxy exists with a black hole at its center, and that black hole isn’t gobbling up the galaxy around it, but rather giving the galaxy a center point on which to rotate, why would it be assumed that everything (including black holes) would be sucked back toward the singularity? (As I understand it, the Milky Way, for example, has a black hole that the galaxy rotates around. Light/matter seem to be at the event horizon, but few if any, fall into the black hole anymore. It’s almost as if an equilibrium were reached (or the black hole was “full”)).
Doesn’t the idea of a Singularity indicate the presence of Space? I mean, the Singularity has to be SOMEWHERE. So if it indeed existed, it was floating/hanging/sitting somewhere… which means that space is infinite, but not necessarily expanding, which is what I’ve read happens after the Big Bang. Space becomes created in the void between items spewing out from the singularity. I believe that the space is not created when a Big Bang occurs, but rather the space is already there. The Big Bang just fills it.
If the idea of space not being created but existing infinitely outside of the Singularity is possible (question 4), wouldn’t it also be possible that there could be multiple “singularities” hanging in space, waiting for their own trigger to blow? Or is it thought that each singularity would create its own universe (thereby creating multiple universes?)
I am wondering if any cosmologists, physicists, or anyone else can shed some light onto these questions. And if there is no explanation that we know now, is the answer “God” reasonable? Perhaps some things are just not explainable, which points us down that path eventually, even if the stories of the OT and NT are also hard to swallow.
Just to address this single point, the big bang means that space itself is expanding which tends to move every galaxy away from every other (and to move more distant ones away more quickly than closer ones), leading to their light being red shifted. However, the galaxies themselves are also moving about relative to one another within space, quite quickly, and in more or less random directions. In some cases (I guess mostly for some relatively close galaxies) this leads to a situation in which the random movement of a galaxy towards us within space is faster than the rate at which the space between us and that galaxy is expanding. In such a case, the red shift due to the expansion of space will be smaller than the blue shift due to that individual galaxy’s random motion towards us, and we will see a net blue shift.
Sure, that’s easy. It was exactly at the point where you’re sitting right now. And at the point where I’m sitting. And every other point, too. Every point is the point where the Big Bang occurred, since the Big Bang encompassed the entire Universe.
For the most part, they are. It’s only extremely close by galaxies that are blueshifted, and that’s because at short length scales, the cosmological expansion is much slower than the incidental motions that galaxies have.
I’m not sure where you’re going with this one, but a Big Crunch singularity (everything falling back together) is exactly the same thing as a black hole’s singularity, just on a grander scale. A black hole doesn’t fill up; no matter how big it gets, anything that hits it will still get eaten. It’s just that, after a while, everything that’s practically speaking going to fall in already has.
Where it was was everywhere.
Moot, since so far as we can tell, space did, in fact, come into existence with the Big Bang.
Ah, the old “god of the gaps”. Problem with that is, it means you have to change your religion every time a gap gets filled in. Religion should be stabler than that.
It was actually much smaller, and if it was a true singularity, it didn’t have any size at all.
The thing is, everything that has a certain size is held up against collapse by some force acting against the force of gravity, which is universal and always attractive (unlike, say, the electromagnetic force, where negative and positive charges, and attraction and repulsion between them, may balance out). So if gravity becomes strong enough to overcome the other forces – i.e. if you cram enough mass in a small enough space – there’s nothing there anymore to stop a total collapse. Thus, the whole thing contracts to a point.
Two points: the early universe wasn’t see-through, so even if we looked back as far as we could (by looking far out into space), we could only see back as far as about 300,000 years after the Big Bang IIRC (that’s without using something exotic like neutrino telescopes or gravitational wave detectors).
The second, more important point: there is no place where the singularity was – everything that today exists was concentrated within the singularity (though not in its present form exactly), remember? So the singularity was everywhere, and space today expands from every point. If you’re having trouble visualizing that (and everyone does), think about a balloon on which you have painted some dots being blown up: the surface of the balloon is a 2D version of our universe, and every dot – i.e. every galaxy – recedes from every other in a distance dependent fashion. If you let the air out of the balloon again, it contracts, eventually (at least in this idealized analogy, if not in real life obviously) down to a point. Now, asking ‘where is the singularity in space?’ essentially amounts to asking ‘where on the surface of the balloon is this point?’, and you can see why the question doesn’t exactly make sense.
Ideally, yes, all galaxies should recede from us (or any other galaxy). However, there’s some additional dynamics to galactic movement that may override that tendency – think, for instance, of two galaxies orbiting each other. For half the rotational period, each one of the pair would, if they rotate sufficiently fast, move towards us, rather than away, and thus be blueshifted (that’s an artificial example of course, but it should explain the general gist).
The big crunch is dependent on the universe being what is called closed – roughly, its gravity is sufficient to eventually reverse the expansion and re-collapse. In that scenario, everything would indeed eventually end up in a singularity again. However, current observational evidence disfavours this possibility – far from slowing down, the universe’s expansion seems actually to be speeding up!
As for ‘how the singularity got there’, there’s no widely accepted theory really, just lots of speculation, from the almost conservative ‘quantum creation’ a la Vilenkin, in which the universe ‘tunnels’ into existence (though if memory serves, there is no actual singularity in this proposal), to the recent speculation of Roger Penrose, in which, after all matter has either decayed or been sucked into black holes and re-emitted as radiation, the photon gas that remains has in a sense ‘lost all sense of scale’, and, though originating in an incredibly dilute, cold state, becomes indistinguishable from a very dense, hot state – a new Big Bang.
It should be noted that far from being theories on how the singularity got there, most early cosmology models mainly concern themselves with how to get rid of the singularity, singularities generally being thought to be unphysical (what, exactly, is infinite density or infinite temperature supposed to mean?), and hence, signal pathological behaviour (i.e. an incompleteness) of the theory, which a better one has to be devised to patch over. So for instance in an approach to integrate general relativity with quantum theory called loop quantum gravity, the initial singularity is replaced by a ‘bounce’, a region of extremely high energy in which gravity seems to become actually repulsive.
The concept of ‘no space’ is difficult to get a grip on, and impossible to visualize, our visual imagination being necessarily spatial. But it’s what the theory tells us, and mathematically, there are no problems at all, for instance, with an expanding space that is not surrounded by any space to ‘expand into’. In the balloon analogy, you have to imagine that really, the surface of the balloon is all there is – which is, of course, again impossible to do, since what one then imagines is a balloon surrounded by blackness or something similar; the absence of representation is something very different from the representation of absence.
So the singularity was not floating anywhere; there was no ‘where’ to float in. It just was (or, well, wasn’t, depending on theory).
Well, there is no ‘outside space’ for other singularities to ‘hang’ in. However, models with some similarity have nevertheless been proposed. One more easily graspable is Lee Smolin’s ‘Cosmological Natural Selection’, in which each black hole essentially contains its own baby universe (the selection comes in when you consider that a) in each black hole, the laws of nature (fundamental constants etc.) may be slightly different, and b) in the totality of all those universes, those in which conditions are favourable towards black hole production – those that have the most ‘offspring’, so to speak – greatly outnumber the others).
Of course, everyone has to decide that for themselves, but to me, that answer only pushes back the mystery – starting with ‘why the universe?’, and answering with ‘because god’, only produces the question ‘why god?’; and if that question is unanswerable/has a ‘mysterious’ answer, then the same may be said of the ‘why the universe?’ question, and there was never any point in bringing god into it.
I’d be lying if I said I understood this. Because it contradicts the idea of a singularity the size of an atom. It also contradicts the idea that space is expanding, since as you say, “the Big Bang” encompassed the entire Universe." If what you say is true, then space is finite. Huge, but finite.
Are you saying that galaxies closer to us that are blue shifted just “appear” to head toward us because of their relative movement to us in their current orbit? Almost like Mars’ retrograde orbit in relation to earth, causing it to look like it moves backward in its orbit for a time before looping and moving forward once again?
I realize a black doesn’t fill up. That was a joke, but it also reflects the idea I was trying to describe, i.e. the black hole isn’t drawing anything else into itself. And thanks for confirming what I was trying to point out, which is that by the definitions as I understand them, black holes are smaller scale singularities. Can you also explain why a black hole stops drawing things toward it? I’m not clear on this, especially on BH’s that are at the center of galaxies. As a black hole “eats”, doesn’t it increase in size, therefore increasing its range to draw material in from?
Same problem as in question 1
Again, this is the same problem. I guess if I believe that space existed before the big bang, we will always contradict on these points. Since I have no proof that space could exist without the big bang, I don’t exactly have a leg to stand on. It’s just a theory of mine, not in line with current thinking.
In the words of the noted philospher Homer J. Simpson, “It’s funny because it’s true!”
Though I suppose a physicist could quibble slightly with that definition. They might rephrase it as “‘Singularity’ is physicist speak for ‘We can prove in excrutiating mathematical detail that we don’t really know’.”
(Because there are a lot of really boring things we don’t really know, too, of course)
I’m afraid that I fail to grasp the reasoning that is leading to this conclusion, and therefore can’t critique it.
Not just appearances; some galaxies really are moving towards us. Really, it’s no more exotic than a car moving towards you, or a person, or a housefly, all of which are possible despite the fact that the Universe is expanding. Galaxies just aren’t all that big, on a cosmological scale.
The thing to understand about black holes is that they follow the same laws of gravity as everything else. Why aren’t we eaten by the Sun? Because we’re in orbit around it. If you replaced the Sun with a one-solar-mass black hole, we’d still be in orbit around it. The only difference comes from the fact that gravity gets stronger the closer you get to a mass, and there’s a limit to how close you can get to the Sun. You can’t have an orbit around the Sun closer than a few hundred thousand kilometers, because you’d end up running into the surface. With a black hole of the same mass, though, you could have a hundred thousand kilometer orbit, or a one thousand kilometer orbit, or a ten kilometer orbit, and it’s when you get really close like that that things start to get weird from gravity being so strong.
The Big Bang is popularly depicted as a tiny point that explodes into the universe. Forget that image. It’s wrong.
It’s true that the *observable *universe was compressed into a tiny point at the moment of the Big Bang. But the observable universe is only the small part of the universe that we can see. The *entire *universe is probably much, much larger than the observable universe, perhaps even infinite.
So, instead of thinking of the Big Bang as an *increase *in size, think of it as a *decrease *in density. The universe at the moment of creation was very hot and very dense. The stuff that would form the observable universe was compressed into a tiny point. But the rest of the universe was of unknown size (maybe even infinite).
At the moment of creation, all of space everywhere was hot and dense. Over time space expanded and things got cooler and more spread out. But there was no explosion from a single point.
As for how everything could have fit into such a small place, remember that there weren’t any protons or neutrons at the time. Only the fundamental particles- quarks and leptons- were in existence. As far as anyone can prove, these act like points, not 3D objects. We can’t observe anything that small directly, so we just have to remember to describe the characteristics of a system like a quark instead of actually trying to define what it ‘is’. So it’s very possible that before quarks met up to form protons and neutrons, and before they got together with their good pals, the electrons, they very well may have been able to sit on top of one another in space. That is, they may have been dimensionless, all the way down to the Plank scale. So it would be less like “How can all those boxes fit in a room that small?” and more like “How can all those thoughts fit in a room that small?”
Just this layman’s attempt to parse the weirdness that is particle physics.
Just to add: one thing to realize about the big bang, and science in general, is that theories are tested by making predictions.
The cosmic microwave background was a key prediction of the big bang and was the point at which physicists started to accept it.
Religious sites like to depict it as a bunch of guys deciding they hate god and therefore trying to cook up an alternative story. It wasn’t like that. Indeed I think the term “big bang” was originally used to mock the theory, but it stuck.
The philosophical point about what caused the singularity, is an interesting one, but it’s outside the scope of the big bang theory. I’d add though that invoking god is rightly vulnerable to occam’s razor, since this entity doesn’t get us any closer to understanding the “first cause”, and there’s no evidence for it.
Chronos: I think the disconnect I have with my first question and your answer is that you are suggesting that the universe could be backed up to a single point, and that point is everywhere. I am sure this make sense to you and other cosmology folks, but for someone like me, it goes back to my skepticism that the singularity was one atom-sized object that held everything we can and can’t see in the universe. Assuming for a moment that is true, I don’t understand how everything can be rewinded to a number of different “spots”. That singularity had to be somewhere, and that somewhere was an atom-sized location. I can see what you are saying (I think). Since the universe was contained in the singularity, all locations within the universe are contained in that singularity. Is that what you are going for?
I didn’t mean to cross the religious/scientific barrier here. I actually just threw that in to ask if the unanswerables are tossed into God’s realm. Perhaps our brains are not capable of comprehending some of the larger issues at hand. But I don’t want this thread to veer off into a religious debate. My fault.
Others have done a good job of answering these (see: Chronos), but here are some more answers…
We will be able to do much better than we are doing now with the Hubble Deep Field and the Cosmic Microwave Background Radiation images we have.
There will probably be a physical limit of our ability to observe the instance of when existence started happening though. That’s just a reasonable expectation though, not an established fact. We’ll see.
The important thing here is that human brains are a subset of universal reality, so, whatever we are able to comprehend will only equal the reality of existence that we are aware of, and that we cannot step outside the bounds of reality to examine existence from another vantage point.
Galaxies that are close enough are bound to their gravitational forces. Galaxies that are far enough are pushed away from each other. Milky Way will be colliding with the Andromeda Galaxy in the next 2-4 billion years because we’re close enough in our local group of galaxies. Similar collisions are being observed throughout the observable universe.
You’re confusing a lot of different observable facts here.
There’s no prevailing or any type of theories about Big Bank singularities ( I think that’s what you meant with your first reference). The cause of the Big Bang is still outside the bounds of our comprehension unless String Theory is proven correct, which seems to be impossible to do at the present time.
The Big Crunch theory has been discarded as a potentially viable cosmological theory. All observations point to a faster and faster expanding universe, to the point of a Deep Freeze… when all subatomic particles will lose all their energy and wither into an eternal energy death. Research “Cosmological Decades”.
You’re wrong about that. We’re 3-dimensional beings but, thankfully, our ability to comprehend logic has proven that space, as we know it, was created after the Big Bang and it did not exist before it.
At that level of speculation, it’s only the established scientific disciplines that can ever hope to give a plausible answer to such questions.
Theories of multiple universes are already considered as potentially legitimate for examination.
My take is that Universal Intelligence ™ is a quality that is inherent to our universe and that as hydrogen atoms can become helium atoms under extreme gravitational forces in the center of stars, so can entities that are based on universal laws, become aware of the processes that created them.
Whatever is a mystery for us now, will not be a mystery at some time in the future. As long as we don’t look for magical explanations, we will eventually know reality.
One of the problems I have with the popular media is the trivialization of the concept of a scientific “Theory.” To a scientist worthy of the name, a Theory encompasses all known data: every observation, measurement, and test of every hypothesis. The Theory must make “falsifiable” predictions (whether we have the capacity to test those predictions or not.)
To a media wonk, a “theory” is synoymous with “wild-assed guess.”
This leads many to object to some well-researched topic with a dismissive, “well, it’s only a theory!”
If an observation (measurement, test result, etc.) falls outside the purview of the Theory, the Theory must expand to include the new data point, or be re-worked, possibly scrapped, in favor of a more inclusive theory.
Especially to those working at the leading edge of the Physical Sciences (e.g. Cosmology, Quantum Mechanics,) we are confronted with the situation where, on a fundamental level, we really don’t know. What is the fundamental nature of matter? At one time, the “Raisin Bread” theory held sway, then the Nuclear Atom, until structure was detected in the nucleus, and so on until today, where the “Standard Model” posits a veritable zoo of subatomic particles. Yet unanswered questions remain: What causes some particles to have mass, and others not? What, exactly, is mass? How does it cause Gravity? Is it the same as Inertia?
At the other end of the scale, General Relativity has made tremendous strides toward explaining the foundation of the structure of the Universe. Both QM and GR have made many predictions, which have been tested and verified to exceedingly fine levels of accuracy. But, on a fundamental level, they can’t both be right, because some areas of overlap have conflicting predictions based on which theory is used.
This is where, I believe, media outlets such as The Learning Channel, Discover, and their ilk do the general public a disservice. While it is true that not everyone in their target demographic has the education to understand the more technical aspects of the subject, “dumbing it down” to the point they do leads many to completely wrong ideas about the topic. When they are referring to a singularity, for instance, which for all practical purposes is a mathematical “point,” with no dimensions, only “location,” they know the audience won’t “get it,” so they use the metaphor “the size of an atom.” But an atom has a size, and volume, which conflicts with the basic idea of a “singularity.”
I once read a newspaper account of a galaxy the Hubble had imaged, which quoted an astronomer as saying the galaxy “had a mass of over 300 billion stars the size of our Sun.” The reporter “helpfully” explained that “mass” is “like weight.” Weight is a force, mass is a property of matter. While one may be derived from the other [F=MA], they are NOT the same thing. How would you “weigh” a galaxy, anyway?
Many of the issues raised in the OP seem to be the result of thought processes engendered by a mass-media take on cosmology.
Take a standard galaxy, put it on one pan of a scale, put your test galaxy on the other pan and see whether it goes down. (You may need a supply of standard galaxies if your test galaxy is very large.)
I’m someone who writes popular articles about science and medicine and history and all sorts of things. That means I have to think about both basic concepts and fine points and try to gauge what set of these my audience will understand and which I have to explain.
I’ve learned not to get too bothered by the kinds of distinctions that set off people here. Yes, mass and weight are different concepts and its important to understand the difference. But for everyday experience mass = weight. It’s only an issue if you have to deal with non-earth gravity. Why bother to drag that in if it’s not needed? The expanding balloon is another example. It’s beloved by people who already understand the concept. But it works badly in practice with people who don’t have any understanding of the concept in the first place. (A 2-D version of the universe? Are you kidding me?) What they envision is a balloon with an interior, rather than a two-dimensional surface only, that grows within space just as balloons normally do when you blow them up with air or helium. The explainer may wind up proving the opposite of the originally intended point.
People like the OP don’t have any of the concepts. They don’t even have the concept that a scientific explanation is different from just sitting around thinking until sometimes feels good as an answer. The concept that earthly “common sense” doesn’t apply at all to the universe and that one needs to start thinking from scratch in a mathematical way is not even a possibility. If it violates earthly “common sense” it’s wrong, or you’re telling it wrong, or you’re deliberately trying to confuse.
As I’ve said before, while the physics gurus on this site are invaluable for good science, they almost immediately tend to lose the people who ask the OPs. They assume the concepts, they assume the math, and they assume that everybody else thinks with the same set of understandings about science that they do. Yet reading the OPs makes clear to me that none of this is remotely true. There’s no one good answer to this. However, I maintain that insisting on the difference between mass and weight to an audience that understands neither mass nor weight is the wrong answer. Or at least the wrong starting point.
OK, picture a hand-held fan, the kind with a bunch of sticks all radiating out from a pivot you can fold it on, with cloth or paper stretched between. Suppose you’re out on the end of the fan, and you see a stick you’re on, and then another one on each side, and more beyond that. You have a notion of the “location” of something as being which stick it’s on. I tell you that the fan has a pivot point, and you ask where it is, meaning what stick it’s on. I tell you that the pivot point is on all the sticks. This is basically what’s happening here, too.
Don’t be so hard on the poor reporter- Gordon Kane did the same thing in Supersymmetry, and that certainly wasn’t a PopSci book. Mass is a funny thing, because we experience it as weight but then science teachers beat that assumption out of you, but when you work with astronomy, you go back to thinking about mass as weight, and when you work with subatomic particles, mass effectively is weight.
I, personally, think this simplification gets a bum rap.
I am not so sure. See, the problem I have is that here, on the surface of the Earth, a person who has a mass of (“weighs”) 75 kilograms (165 pounds) exerts a force of 75kg * 9.81m/s[sup]2[/sup] = 735.75 Newtons on the ground. On the Moon, with 1/6 the gravity at sea level on the Earth, a 75 kilogram person exerts a force of 122.6 N (27.5 lb). In free-fall (or in orbit) a 75 kilogram person effectively “weighs” nothing, and exerts no force on his surroundings. On the surface of a world with ten times the gravith of Earth, a 75 kilogram person would exert a force of 7357.5 N, and would appear to “weigh” 1650 pounds, or more than 3/4 ton.
In other words, the mass of a 75 kilogram person is invariant in all these cases, but in order to refer to the “weight”, the gravitaional acceleration must be specified. In my comment about the “weight” of a galaxy, in its own gravitational field, it has no weight. In which gravitational reference frame must it be put for the weight of a galaxy to have any relevance? Granted, most of the time when mass is discussed it is in the context of “here on Earth, with a gravitational acceleration of 9.81m/s[sup]2[/sup] (32.2 feet/s[sup]2[/sup]).” But, why would a person intentionally use a less-precise term, when no additional information or clarity will result?
In the early stages of the space program, reporters were fond of telling their audience that the astronauts in orbit were “beyond the pull of Earth’s gravity.” As if you could get a few dozen miles from the surface and gravity no longer had any effect. To this day, I still find people who hold this view, and are incredulous when I try to explain that the astronauts are in free-fall.
The point I am trying to make is, why can’t populizers of technical material tell the public the truth, without perverting and distorting it so much that it no longer correlates with reality? One of my favorite authors, Isaac Azimov, was a master of this technique. He could take any topic and reduce it so that the common person, with no prior familiarity or math background, could understand the subject, and still be true to the science. While he is most widely known as a science-fiction author, he was a PhD professor of Biochemistry at Boston University, and wrote or edited over 500 books in his lifetime.