h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

There are actually some fairly good reasons to believe that the Big Bang theory is incorrect.

Point 1: It violates the first law of thermodynamics.

Imagine a balloon with tiny little galaxies drawn on it in ink. Now imagine that the balloon is being inflated. Although none of the ink galaxies move on the surface of the balloon, they all end up farther apart from each other than they were, because the surface of the balloon has expanded. This is an easy-to-understand model of what the Big Bang theory states: the three dimensions of our universe are expanding outward (in some higher dimension) while space itself is closed (like the surface of a sphere).

Now, consider this: for objects with mass to be able to move farther apart, they have to gain energy (gravitational potential energy, to be exact). Now, if all the galaxies are "moving away" from each other (and at faster and faster rates), this means that the gravitational potential energy of the galaxies is steadily increasing. The expansion of the universe requires that huge amounts of energy be created out of nothing, which violates scientific dogma.

Point 2: It cannot be explained without ad hoc theories (made up just to explain one piece of evidence and have no other reason to be true).

Some scientists think that if the universe had enough mass, the universe would eventually cease expanding and collapse inwards in a "Big Crunch". However, this would require that gravity acted "outside" of normal space-time (like a galaxy on the surface of the balloon pulling at a galaxy on the other side "through" the empty space in the middle). Although this idea is possible, there is no evidence to support it, and there should be observable signs that this is so (but we haven't seen them).

Also, if the mass of the universe were great enough to cause the universe to collapse (greater than the mysterious force that creates energy and is causing the expansion), then the universe should never have been able to explode at all! The attractive forces inside the original singularity would have been too great. Even if there isn't enough mass to stop the expansion, we still can't explain why the universe seems to have expaned as quickly as it has. Some scientists have tried to solve these two problems with a "antigravity force" that existed only for a brief moment of time at the beginning and then ceased to exist. There's no evidence for that, either -- another ad hoc theory.

Point 3: There are very few pieces of evidence supporting the Big Bang (or making it necessary).

There are really only two bits of information that would lead scientists to think that the Big Bang ever occurred. One is the redshift of distant galaxies, which leads us to believe that they are moving away from us in all directions. There are actually other explanations of this observation, and we can't prove or disprove any of them. The other is the Cosmic Background Radiation. The CBR is a relatively strong argument in favor of the Big Bang (compared to the others, at least), but we really don't know what it means. None of the evidence usually given in favor of the Big Bang can rule out other possible theories (there are a bunch of them, some of which are quite interesting and perhaps even possible).

In short, we really don't know how the universe began, and we can't even begin to make the necessary measurements to figure out how it started. We can observe many things, but we don't know enough to determine what they mean.

I suspect that the Big Bang theory won't last another hundred years. Then again, I've been wrong before...

[bows respectfully]

--Caledonian

Hmmm??
Some observations from a non-sientist.

"Point 1: It violates the first law of thermodynamics."
Why? Two reasons I ask.
a. How do you know that the total "potential" energy before the Big Bang didn't greatly outweigh the energy needed to create the universe, this would comply with the first law . Surely some kind of unstable field could have been caused to colapse by random fluctuations releasing huge amounts of energy (doesn't a vacuum have an energy potential?). There's no reason to think that there was litarally nothing in existance before this universe came into being. Just nothing that we know anything about. Anyway, the "huge amounts of energy" are only huge from our viewpoint. They may be almost insignificant.
b. Was the first law of thermodynamics valid before the Big Bang. As far as I knew. The physical laws were laid down at the same "time" as all the matter and energy was created/released. So it might not apply.

Where did "all the galaxies are "moving away" from each other (and at faster and faster rates)" come from. I thought the rate of expansion was slowing.

To gain gravitational potential energy all you have to do is transform another kind of energy into it. The expanding universe has kinetic energy which is being converted into gravitational potential energy. The question is, will the universe have enough energy to spread thin enough for the gravitational forces to become too weak to interact. Or will the kinetic energy run out and gravity start pulling things together. If you throw a ball up in the air (not much kinetic energy) it will come back down. If you could launch it fast enough (loads of kinetic energy), it wouldn't. There is no "mysterious force that creates energy and is causing the expansion" in the same way that there is no mysterious force that makes the ball go up and up. It was caused by the initial explosion (the throw).

"Point 2: It cannot be explained without ad hoc theories (made up just to explain one piece of evidence and have no other reason to be true)."
I still haven't heard Gravity explained without ad hoc theories and I'm not about to stop believing in that.
I also don't think that any "antigravity force" is needed for any explanations. Then again, I don't think that the "gravitational constant" always was (or will always be) constant. Just that it won't change much in my lifetime.

"Point 3: There are very few pieces of evidence supporting the Big Bang (or making it necessary)."
I've read of several pieces of evidance supporting the Big Bang but no whole proofs and without a whole proof none of the evidence could ever stand up on it's own, 'cos then it'd be a proof. But surely it is necessary, as the universe is expanding and must have come from somewhere. I'm not against all the matter existing "from the beginning" and exploding outwards due to some strange random mix of matter causing a massive explosion. It's ugly though and doesn't tell us where all the stuff came from before that.

I don't know the answers either but I'm still looking.

[doffs cap respectfully]

Dr Goof Lithium

1a) The point I'm making is that, because the galaxies are moving farther away from each other, their potential energy is constantly increasing. However, the galaxies have negligible kinetic energy (compared to the expansion), and their inherent kinetic energy isn't what's causing them to move farther apart! Energy is just appearing out of nowhere in the form of gravitational potential energy... and scientists just ignore this point completely.

Oh, and Hubble's Law is where the "galaxies are moving at faster and faster rates" comes from. It states that the redshift (and presume rate of recession from Earth) of distant galaxies is proportional to the distance of the galaxies from Earth. Additionally, the expansionary model of the universe implies that the farther away a galaxy gets, the faster it will recede. There's actually supposed to be a boundary past which we can never see any farther, because the galaxies are "moving" away faster than the speed of light. This implies that the gravitational potential energy of those galaxies is infinite...

1b) I don't know if the First Law of Thermodynamics was valid before the universe began (if it did begin). However, I should think that it's valid NOW -- and the galaxies are CURRENTLY gaining energy from nowhere.

The expanding universe does not have kinetic energy. That's the weird part. Because it's space that's expanding, the galaxies aren't actually moving through space relative to us -- they're just getting farther away.

2) An ad hoc theory is one proposed for the purpose of making sense of one inexplicable observation and one observation only. For example, it has also been suggested that the redshift might be the result of light vibrating more and more slowly as time passes. No one has ever seen this happen, and we have no particular reason to think that it might happen -- but it explains the redshift. Ad hoc theories are generally not regarded with a great deal of respect in science (and with good reason).

3) First, we don't even know that the universe is expanding for sure. That's my entire point!

Secondly, there are many theories that we can test and check; most of the time, the first theories that scientists come up with turn out to be false or incomplete later. (Which makes sense.) However, the flaws in these theories ususally are demonstated only through observations of effects that the theory can't explain. At our current stage of technological development, we are unable to make any observations of the universe at large that would allow us to check our theories, so we have to take suggested explanations with a grain of salt. We don't know if there's a redshift because the universe is expanding, or because light's vibration really does slow down, or for some weird reason we haven't even thought of yet. We just don't know -- and we probably can't find out.

Thirdly, we still don't know where the universe came from even if the Big Bang theory IS correct. Where did the singularity come from? Why did it exist? Why did it suddenly change?

We need to keep looking for answers -- and be ready to discard those that may not be correct.

[bows respectfully]

--Caledonian

I thought Hubbles law stated that galaxys that are further away will be moving faster than those nearer to us. Not that the rate of seperation was getting faster the further away they were.

If space was expanding and not the galaxys moving appart surely there would be no "red shift".

"The expanding universe does not have kinetic energy." - has all the kenetic energy from the initial explosion been converted to other forms already? What would be wrong with the expansion of the universe being caused by the space having the kinetic energy.

[doffs cap respectfully]

Dr Goof Lithium

*wanders past*

I've sworn not to get involved in any more arguments about physics until I know enough physics to actually argue meaningfully...

So I'll be on my way.

*wanders out again*

26199

Imagine an expanding balloon as it is inflated. A given section of the balloon will expand by a certain amount; although this amount is proportional to the size of the section of the balloon we're talking about, it will get larger in an absolute sense as the section gets bigger.

In other words: 1% of 1,000,000 is a lot bigger than 1% of 100, even though it's 1% of each. If a galaxies is 200 billion lightyears away, it will be "moving away" at twice the rate of an object that is 100 billion lightyears away... and as it moves farther, it gets faster.

The expanding universe theory says that the farther away an object is from any one place, the faster it will recede... the faster the galaxies seem to move, the faster they go.

No, there would be a redshift anyway. Imagine the space between the wavelengths of the light getting larger by a tiny amount as time goes on... the light would seem to be reddened if it traveled for a long period of time.

THERE WAS NO KINETIC ENERGY FROM THE INITIAL EXPLOSION. That's what's so weird about the Big Bang theory -- nothing moves, but everything gets farther away. Besides, the expansion model requires things to be gaining energy at an ever-increasing rate, anyway, which can't be explained by a transference of kinetic energy.

[bows respectfully]

--Caledonian

Hmmm... I see. still not sure about some of the receding stuff and the assumption that the Hubble constant is really constant (has this been proved?). I'll do some thinking and see if I can get it straight in my mind.

I wish I'd paid more attention to physics at school..

[doffs cap respectfully]

Dr Goof Lithium

As far as our observations can determine, the Hubble constant is correct.

The inflationary model of the universe has among its consequences the effect that the farther away an object is from any observer, the larger the rate of increase of distance between the observer and the object.

We don't actually know if this happens, however; this is merely a logical consequence of the theory, and is not contradicted by the evidence.

I simply find it annoying when scientists gloss over the (major) flaws in the Big Bang theory, and then ridicule much smaller (relatively speaking) flaws in other theories.

We don't know as much as we think we do. Historically, that's been a pretty good rule of thumb; try reading a good, through history of science. It'll make you realize how often the "truth" has changed radically over the years... very disturbing stuff.

[bows respectfully]

--Caledonian

Don't worry, I know how often the "truth" has changed radically over the years but it's not just restricted to science. Philosophy, religion and history have all had their fair share of re-writing/correcting/updating/ignoring etc. We'll probably only know how it all started when we watch how it all ends.

[doffs cap respectfully]

Dr Goof Lithium

On one hand I'm sort of flattered that my meager entry has generated some discussion, but on the other hand I'm sort of intimidated because I am far from an expert! Anyway, hope you enjoyed reading the entry even if you didn't agree with it, and I'll see you around.

Hmm - this is the question of whether the 'Cosmological Constant' is non-zero, is it not? That is, whether empty space will expand or contract when left apart from mass.
And the Hubble Constant is the current rate of expansion? It's been a while - want to get things straight.

Well the first thing is that some variants of the Big Bang theory have a Cosmological Constant of zero - it's only more recently that people have started to wonder if Einstein's "greatest mistake" might have been right after all. Complaints about energy appearing (or dissapearing) thus wouldn't invalidate all big bang models - just some.

Second thing is that while things that are far away would accelerate away from each other faster, their gravitational potential energy would be vastly reduced. (1/r law). So, in effect, everything gains an amount of energy proporrtional to it's mass.
If you wanna fix this, the easy way is to simply have the speed of light constantly reducing. In fact, I seem to recall that if we do live in an inflationary universe, then it has to - but that's just memory. Or you could muck around with G, or decide that Higg's Bosons spontaneously decay (or are created) over time. The options are endless. But I prefer a varying speed of light, since it explains other stuff too.

Those are some interesting points, but (to my mind at least) they don't change the fundamental issue here.

The Big Bang theory was formed on the basic of two observations: the Hubble effect and the Olbers (Olber's?) Paradox. The only evidence that seems to affirm the Big Bang is the Cosmic Background Radiation, and even that has several explanations.

Frankly, there are several other scientific hypotheses about how the universe came into being, and they're all consistent with the data. (Some are more consistent, some are less.) The Big Bang is currently the best, but I'm skeptical of our ability to test the hypothesis well.

Why exactly is space "expanding" in the first place? That's the real question, and one we can't answer.

[bows respectfully]

--Caledonian

what's Olber's paradox?

It's based on the observation that the night sky is dark. If there were an infinite number of others stars/galaxies, then the cummulative effect of all that light would mean that we'd see a star wherever we looked. There must be a reason that we don't, and several hypotheses have been suggested to explain the paradox. One such explanation is that distanct galaxies are "moving" away from us "faster than light" due to the cosmic expansion and carrying their light with them. There are other explanations, though none of them really seems to explain what we see.

Oh well...

[bows respectfully]

--Caledonian

Oh yeah - I remember that now - had forgotten the name...

cheers

Is the speed of light constant just within this universe or is it assumed to be constant regardless of this universe?
If the speed of light is just constant within this universe then if space is expanding not just the distance between things then wouldn't the "red shift" caused by expanding space be nonsense as the speed (distance over time) would change as the expansion happens making the effect non-observable. If it is assumed to be constant regardless of this universe, making the "red shift" caused by the expansion of space valid, then we know more about the "pre-universe" than I thought.
Maybe I'm just confused again.

There are reasons for believing the speed of light has decreased - not constant at all anywhere - supposedly it explains why the universe is so homogenous on the broad scale. Hmm. A likely story...

I don't understand the rest of your post...