What would a purely newtonian universe be like?

[Modax]

imagine an alternate universe where there is no relativity. The passage of time is the same everywhere, and at all (relative) velocities. E=MC2 is true, and all the universal constants (including c) are the same as our universe. Quantum mechanics is the same as our universe, and all the forces and particles are the same. A rocket could keep on accelerating indefinately until it runs out of fuel, eventually overtaking its own light, and its mass does not change. Time and space are eternal and unchanging, while matter and energy formed out of the void 14 billion years ago for reasons unknown.

Now, what would the implications of this be? Would life be possible? How would life be different?

I'm no physicist, but one thing I can think of is that it would be relatively easy to accelerate electrons or protons to arbritarily high speeds, enabling some form of FTL communications. (But would wireless communication with electrons work?) Interstellar travel on the macro scale is easier, but not that much easier, because there are obviously still no warp drives or hyperdrives. I eagerly await the ideas of the more physics savy people on this board.

[Samuel]

The position of Mercury would be different.

Earth wouldn't be bombarded by certain high energy particles because they decay too fast.

How is c the same everywhere and relativity not true? Relativity is based on the fact that c is a universal constant and no matter your velocity, c is the same.

[Modax]

In this universe, you will measure the speed of light differently depending on your relative velocity. But you can't accelerate photons past c (how do accelerate something with no mass? What do you push on?)

Now, I don't know if that even makes sense. What would the implications be if photons propogated at infinte speed, allowing you to see across the universe in "real time?" That would make gamma ray bursts a lot more dangerous.

[Modax]

Okay. I see what you're saying. Yes, if you accelerate towards a star, its light is moving towards you faster than c.

So c just describes the speed of the propagation of photons relative to a body at rest.

[Steel]

A purely newtonian universe would just collapse under gravitational forces. Without expansion of spacetime a "static universe" cant exist.

[Modax]

Interesting. I wonder why Newton and his contemporaries did not think of this implication of his theory.

Perhaps in this universe there is some sort of "dark energy" which negates the effects of gravity on the scale of billions of lightyears.

Also, how long would it take for gravity to consolidate the universe like that? Would it allow enough time for life to form?

[Samuel]

Interesting. I wonder why Newton and his contemporaries did not think of this implication of his theory.

Perhaps in this universe there is some sort of "dark energy" which negates the effects of gravity on the scale of billions of lightyears.

Also, how long would it take for gravity to consolidate the universe like that? Would it allow enough time for life to form?

They thought the galaxy was the entire universe and that it was young.

[Steel]

Interesting. I wonder why Newton and his contemporaries did not think of this implication of his theory.

Perhaps in this universe there is some sort of "dark energy" which negates the effects of gravity on the scale of billions of lightyears.

Also, how long would it take for gravity to consolidate the universe like that? Would it allow enough time for life to form?

Newton assumed that the universe was infinitely big and uniform density and then he made the assumption that all the gravitational forces would cancel out. It turns out that you can demonstrate that the force on a test mass in an infinite homogeneous universe is arbitrary (can take any direction and magniture you like) and such a configuration is therefore impossible, first spotted by Lord Kelvin.

As for collapsing the universe, it depends entirely on the intial conditions, in this GR free universe you have constructed it is concievable that the universe could consist of just 2 particles moving apart at many times the speed of light and therefore the universe will never collapse. You can extend that idea to a more likely type of universe (one with more matter) quite easily and so get any range of values for the collapse time between 0 and infinity. I mean i suppose you could think about local collapse, but local structures like clusters and galaxies can keep going happily for fairly arbitrary periods of time.

[CaptainZoidberg]

I think it would imply that the speed of light is relative.

Other than that, I think the world would be relatively similar to the one we inhabit today (unless it would impact bonding and orbitals and the like, in which case everything would be fucked up).

A purely Newtonian universe would just collapse under gravitational forces. Without expansion of spacetime a "static universe" cant exist

What if everything was orbiting some central body? Or what if the electric forces prevented gravity from dominating (remember that E = 1/2mv^2 in Newtonian dynamics, so there wouldn't be black holes from which nothing could escape)?

[Wyrm]

There would be no solid matter, no chemistry and no nuclear physics.

The Pauli exclusion principle drops out naturally from relativistic quantum field theory regarding particles with half-integer spin. In your non-relativistic universe, such quantum fields would be non-relativistic, and the Pauli exclusion principle that naturally falls out from relativistic fields disappears. That means all fermions can occupy the same state, just like bosons. That means protons and neutrons can all occupy the same nuclear energy level, so you get no interesting nuclear physics, just nuclei that get heavier and heavier and charged more and more. This means that all electrons can occupy the lowest energy level in the atom, and you get very boring atoms. This means atoms will not try to stay out of each other's way (because atoms with the PEP would have to have at least some parts of them having a different momentum when their positions are the same).

It would be a boring universe.

[open_sketchbook]

A purely newtonian universe wouldn't work, as I found out while trying to create one for a comic. (it's a homage to victorian scientific romance, so it uses a mishmash of old theories and scientific models) Basically, you'll have to gut physics and change everything to even get a working universe that superficially resembles our own, and even then heavy suspension of disbelief is needed.

There is a reason we abandoned the pure newtonian model of the universe; it doesn't work.

[Modax]

Wow. Just wow. A lot of trekkies seem to think that Faster Than Light travel is easy and can be invented in this universe, by ordinary humans.
But nevermind that. Faster-than-light doesn't even work IN A UNIVERSE DESIGNED FOR FTL TO BE POSSIBLE. Its almost like reality conspired against intelligent life forms everywhere, for the sole purpose of making sure they can't (easily) build interstellar scale civilizations.

[open_sketchbook]

Hell, likes ignore the basics here and say, yes, this universe works. Imagine for a moment how much Delta V you'd need to accelerate to the speed of light or faster. It'll be insane! And all that reaction mass is going to wiegh a hell of a lot, slowing you're acceleration down. And once you've reached the speed you want, you need to expend that reaction mass again just to slow to a stop. To top it off, with modern space engines, you might as well be travelling STL, because it'll take so long to accelerate to any meaningful speed.

For space opera, just break a fundamental law of the universe with some handwavium. It'll be easier for you, and more than likely easier for you're fictional interstellar empire-to-be.