Is it likely that in a different universe, Newton's Laws would still be valid?
Much has been said about how remarkably fine-tuned the many laws of physics and constants to have provided for such an universe we're familiar with today. But astrophysicists also think and speak of "multi-verses", where other universes can and have existed with a different set of laws of physics and constants. Nonetheless, how likely is it that Newton's Laws would prevail in most or many of them, even as other things such as particle (both fermions and bosons) masses and properties should be different? Could it be that Newton's Laws, like weeds, just crop up nearly everywhere? A much harder question: What would be some of the necessary conditions for Newton's Laws to "thrive"?
This is just a free-for-all question, I'd like some opinions on this speculative subject. There are no right or wrong answers.
A more pointed question would be, "Are Newton's Laws independent of other laws and constants? For example, could Newton's Laws prevail with or without String Theory?"
Graham P, I can just re-imagine that epic scene in "2001: A Space Odyssey", where moon astronauts uncover the sentinel, standing before a breadbox-sized one.
Noether's Theorem points the way to understanding why we can have Newton's laws, whcih is that existence of symmetry provides for things like conservation of momentum. However, such symmetry can arise in any number of ways that aren't related to "sub rosa" processes, such as quark dynamics.
Vasek, you are, of course, right in pointing out that Newton's Laws are only true "in the approximate sense", which suggests that such "approximately true laws" are a consequence of the "real laws" of this universe. What I am arguing here is that even if this universe had a different set of "real laws", it could be that there will still be a Newton V.02 coming to the same conclusions as Newton V.01 did.
As an analogy, Bernoulli's hydrodynamic equation could still be useful, even if nuclear and molecular forces of the fluid medium should be different. It has a generality that could be fairly independent of those atomic processes.
Lots of wild and woolly speculative stuff here, eh?
I think Brian's assertion that an universe "NOT supporting [Newton's Laws] might mean that [it] wouldnt last long" is closest to the mark. I think it would take a fairly bizarre universe to not even have approximate linearity in time and space to permit Newton's Laws, and so it could be that the chances of it either be of any interest or have any persistence are slim.
Vasek's lengthy reply to this presumes that Newton's Laws aren't "correct" because we know now that they are only approximations "of the real thing". But that is missing the point of this question, which is that we could still find Newton's Laws in other universes as "mere approximations of the real thing", which can vary and yet still yield the same approximating Newton's Laws.
- Anonymous9 years agoFavourite answer
in the multiverse theory, there are infitinte universes. so there are infinite chances that during the big bang, something was different, and thus the universe would or would not support newtons laws. NOT supporting them might mean that the universe wouldnt last long though.
read asimovs "the gods themselves" look past the drama, and characters and you see how one of those universes could be. then take that to the extreme.
edit: i think the "12 possible" are not universes, but dimensions. (remember reading something about that, and the mathmatecal echos that could be dimensions possible, or could just be echos)
- ☮ VašekLv 59 years ago
Well, if I am to nitpick, they don't work in our universe, do they?
1: "Every body remains in a state of constant velocity unless acted upon by an external unbalanced force."
There are some concerns with this law on the microscopic scale. Primarily because we might not know what a force is, how exactly velocity is defined and what is its actual value, and, for that matter, what a body is after all. Let's think of a neutron beam shining through a narrow slit. According to Newton, they are a train of rigid bodies going at a constant velocity. They don't bump into anything and if we neglect gravity, there is simply no external force that could visibly alter their velocity. Yet they don't continue at their original velocities beyond the slit, displaying an interference pattern at all possible angles instead.
2: "A body of mass m subject to a net force F undergoes an acceleration a that has the same direction as the force and a magnitude that is directly proportional to the force and inversely proportional to the mass, i.e., F = ma."
This can hardly be considered a law if one does not provide any other means of calculating the force: the second law then becomes the definition of what a force actually is, with (1) as an immediate corollary. However, if we accept the fact that force vector may be taken from some other part of dynamics, e.g. the Newton's law of gravitation, Coulomb's law or the formula F = - grad U, then Newton's second law is compromised in our universe by special relativity, because—even though the fact that the corresponding formula might have the same form—m can no longer be an intrinsic property of the object and a is not the derivative of velocity with respect to time.
3: "The mutual forces of action and reaction between two bodies are equal, opposite and collinear."
This law is known not to work, again due to special relativity, because it expects the action and reaction to happen simultaneously, and simultaneity is relative. It is rescued in the field theory, where all interactions are local and thus simultaneity can be spoken about. However, there was no such condition in the original statement, rendering in imprecise.
As a conclusion, there are corrections to all these basic laws in our universe, thus an example of universe where they aren't valid is obvious.
For the opposite, let us just take our universe in the state it was known to Newton and his peers, and let's assume that the great experimental prodigies of the late 18th and 19th century just confirmed that state of knowledge because, hypothetically, it was final. Everything seemed to work, so let's assume that it did. Let's assume there were no "clouds", so that Lord Kelvin could festively close the discovery of natural laws in 1900. We would get a world without special relativity and quantum mechanics (maybe, if we go deep enough, without particles), but if it's mathematically consistent, it could very well exist.Source(s): Wording taken from: http://en.wikipedia.org/wiki/Newton%27s_laws_of_mo...
- Anonymous9 years ago
Well some theories state their are infinate possibilities and things can be so similar that it's only different down to a tiny little aspect. Some state that their are many universes and are somewhat similar, like technology, but people and other smaller aspects may differ. Some state their are only 12, where each are unique and different in their own way. Some sttate their are only two. One being the "possitive" and the other, the "negative". (E.g. good you and bad you.) I personally believe their are limited multiverses, but they don't differ too a point where it unreckognizable.
- Graham PLv 59 years ago
It is quite possible. Relativity or string theory need not be necessarily true. The universe need not be 11 or 12 dimensions. It could be 2D like on the game "life".
The velocity of light "speed limit" seems rather arbitrary. It is as if God said "Let there be light travelling at a set speed" and all of spacetime had to twist itself to fit in with the rule.
Smolin's evolutionary "baby universes" model suggests that speed limited relativity may a design feature to keep developing planetary or galactic civilisations separated.
Dr Kaku believes we may have alien robots "the size of a bread box" on the moon waiting for us to get civilized like on 2001 A space Odessy. Carl Sagan's viruses from his book "Diseases in Space" are a more likely vehicle for space exploring nano-machines.
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- 9 years ago
All physics Laws apply in one frame of reference, like ur sitting still now on ur chair infront of ur computer, when actually, ur revolving with earth around itself and around the sun anddd around the center of our galaxy (moving with the sun) and our galaxy moving in space as one body. As for Newton's Laws or any proven physics laws they d apply anywhere. The rates might differ, the numbers might differ , the constants might differ, but the Law remains, cos any constant is actually constant in our frame of reference but looking from third person point of view its a variable. Long story short, Laws are the same, rates and constants might differ because they were calculated related to OUR environment and circumstances, in other circumstances they will differ but still under the same Law.
PS: The speed of light is where physics Laws change , only that case , because it is the definite speed , the limit, which in classic physics doesnt apply, but thats the only case.
- KoshkaLv 49 years ago
I recall watching Hawking Universe, he talked about how a very few and very slight irregularities in distribution of newly created sub atomic particles, resulted in the universe we live in. He mentioned that had the explosion resulted in uniformly distributed particles, gravity would have just all kept them apart and the universe would not have become what it is now.
So, we could assume that in a 3d space 1d time such as our universe, the laws would be the same.
As an aside from your question, what I find baffling, is that we are still part of the initial explosion, since the universe is still evolving, and perhaps the end of the explosion could be the end of the universe.
What is also quite baffling is strange things like dark energy and how it affects the evolution of the universe. And even more baffling is the possibility that, again, since the universe is still evolving, we do not know what it might evolve into in billions of years from now. I mean, the fact that we exist as a biological spices and that other forms of life might very well exist on other planets, does not necessarily mean that we are all the "be all and end all" of the universe's evolution into "something else".
Back to the question, what would happen in a universe with one more spatial dimension than ours could be perceived as different because of that extra spatial direction.
Vasek the quantum guy! =)
Hey, you always blow my mind. But about your neutron beam and just for the sake of looking at it from a different perspective. Doesn't their going trough the slit itself cause them to spread out?
I am not saying that Newton's law applies in microscopic scale, but perhaps it is our perception of the same law that applies.
I am not as knowledgeable as you in QM but, isn't tiny stuff like also connected to 2d space?
What is the value of a cube in 2d?
What is the value of pi in 1d?
Our perceptions of the physical world and the measurements we use to describe it could all be linked together, no?
I was not going to add anything, but just for fun, think of an infinite static universe that would contain an infinite amount of uniformly distributed “conscious” dots with same mass. The very notion of gravity would be perceived and interpreted differently for these dots, for they would think of it as a force that keeps them at a certain distance from one another, they could conclude that gravity is a balancing force.
The notion of time would need a different interpretation, it would just be there to allow the entities to think and exchange “thoughts”, hard to say if they would have such thing as the notion for speed or displacement, except as imaginary. But then again, perhaps they could have “imaginary” concepts (imaginary, for them), which are part of our physical reality, that could allow these dot entities to derive our gravity, as we know it in our universe, and ascribe it another name, like "super imbalance" or something.
Perhaps they would see it as an "new and mysterious" potential property for gravity (that they percieve as balance) in their universe, they could come up with a mathematical proof for “skipping” over to another entity 1 or many dots away, although it would be impossible for them to achieve it, they might very well have a cold hard mathematical proof, that displacing one dot could, change the entire configuration of their universe.
So it is a matter of interpretation of whatever information and theoretical models that are provable with math, the entities in a different universe would have.
Conclusions, things may not be what they appear to be ;)
- mw451Lv 59 years ago
"2001"??? Huh? That has nothing to do with your question.
Newton's Laws are Universal, anywhere.
Newton's Law doesn't need to "thrive", it's proven.
"...astrophysicists also think and speak of "multi-verses", where other universes can and have existed with a different set of laws of physics and constants." -- oh You have? Who?
I'm no astrophysicist, but I know one who can de-bunk their bunk.
- Kevin7Lv 79 years ago
We do not really know, even if other universes really exist
- 9 years ago
I agree with Salmon, excellent answer ! : ) Your very smart & wise!
- MeLv 49 years ago
His laws are very general so they apply anywhere, no matter the universe.