[Space] Ditching Relativity, with minimal collateral damage

[vicky_molokh]

Greetings, all!

Probably the easiest solution to resolving many paradoxes emerging due to FTL technologies in Space/Spaceships is to simply ditch relativity. However, this cannot pass without consequences. So . . . this leaves some holes to be patched. Here are some that I figured out:

• Gravitational time dilation. I suspect this may be stated to simply not occur in this universe, however see below.
• Frequency shift. Blueshift/redshift. Can this be ditched too without consequences? Or can it be harmlessly attributed to light being slowed down/sped up slightly below/above its normal vacuum speed while under the effects of gravitational force? (I guess gravity is most likely a force in this universe, but not sure).
• Light deflection and gravitational time delay. Can either the freefall universal rule be applied to photons, or a law of nature state that the freefall rule applies twice to photons/light, without any further consequences?
• Gravitational Waves. Can they be applied to a non-relativistic universe by simply fixing their speed at either c or infinity? Are there better solutions?
• Orbital physics. Orbits no longer decay? Orbits decay as usual with slight change in explanation? Anything else?
• Black hole physics. Do these become simpler by simply stating that the 'horizon' is a de-facto case of everything simply being pulled in with enough acceleration to reverse the direction of a photon trying to come up from the black hole surface?
• Anything else?

Thanks in advance!

[thrash]

Originally Posted by vicky_molokh

Orbital physics. Orbits no longer decay? Orbits decay as usual with slight change in explanation? Anything else?

Orbits mostly decay due to drag from the atmosphere, however tenuous. Stellar wind pressure and other subtle effects (e.g., Yarkovsky) accumulate over long (~Myr) timeframes to shift orbits around. So far as I know, these dominate any relativistic effects.

[Mysterious Dark Lord v3.2]

Ditch relativity and what you have left is what is called "Classical" physics - i.e. what they used to think before Einstein showed up. I suggest you look up GURPS Steampunk, which has a section devoted to Classical physics and it's dearest child, the luminiferous ether.

[Langy]

You can ditch one single aspect of relativity (the no special frames of reference one) and still have the normal stuff that relativity gives you but also have FTL via a non-relativity-sensitive hyperspace type thing.

[Captain-Captain]

GURPS Lensman (Well, the Lensman stories) had stats for a relativity bypass. 100% real world workable IF repeat IF you can separate mass from inertia.

[vicky_molokh]

Originally Posted by Captain-Captain

GURPS Lensman (Well, the Lensman stories) had stats for a relativity bypass. 100% real world workable IF repeat IF you can separate mass from inertia.

If I remember correctly, this wasn't exactly the case. What will be the end velocity of an inertialess object (1kg, but actually 0 for purposes of inertia) that gets hit by a 1k object that moved at 1ms^-1? (Assuming completely rigid objects.)

[teviet]

Since relativity is the true depiction of what actually goes on in our Universe, a universe without relativity would need completely different fundamental physics (i.e. quantum field theory) tuned to give the same "classical" effects. But that's okay, since quantum field theory is pretty much offstage in any game (while relativistic effects can be quite important).

To get a self-consistent classical nonrelativistic world, you pretty much just need to add one thing: a luminiferous ether. For the points you mentioned:

Originally Posted by vicky_molokh

Gravitational time dilation. I suspect this may be stated to simply not occur in this universe, however see below.

Doesn't exist.

Originally Posted by vicky_molokh

Frequency shift. Blueshift/redshift. Can this be ditched too without consequences? Or can it be harmlessly attributed to light being slowed down/sped up slightly below/above its normal vacuum speed while under the effects of gravitational force? (I guess gravity is most likely a force in this universe, but not sure).

Doppler shift due to motion relative to the ether still exists; gravitational redshift would not exist.

Originally Posted by vicky_molokh

Light deflection and gravitational time delay. Can either the freefall universal rule be applied to photons, or a law of nature state that the freefall rule applies twice to photons/light, without any further consequences?

I don't think this will exist; light would be a wave propagating through the ether, not a particle subject to gravity.

Originally Posted by vicky_molokh

Gravitational Waves. Can they be applied to a non-relativistic universe by simply fixing their speed at either c or infinity? Are there better solutions?

Won't exist if you treat gravity as Newtonian: i.e. instantaneous action-at-a-distance.

Originally Posted by vicky_molokh

Orbital physics. Orbits no longer decay? Orbits decay as usual with slight change in explanation? Anything else?

No decay due to gravitational radiation, but that's unnoticeable in the Solar system. Very small corrections to planetary orbits, especially Mercury, but only noticeable with precision measurement.

Originally Posted by vicky_molokh

Black hole physics. Do these become simpler by simply stating that the 'horizon' is a de-facto case of everything simply being pulled in with enough acceleration to reverse the direction of a photon trying to come up from the black hole surface?

They no longer exist, since there is no gravitational redshift.

Originally Posted by vicky_molokh

Anything else?

Well, it means a complete rewrite of the laws of quantum mechanics as well. You're basically replacing the existing laws of nature with a completely different set that gives some of the same classical effects, and you have some freedom to choose which ones to mimic.

For instance: do nuclear reactions exist in your universe? Maybe, maybe not, or maybe there are completely different reactions in their place; the underlying mechanisms would be different. Without E=mc^2 they would not be associated with a change in the "rest mass" of the constituents. Antimatter and total conversion make no particular sense without relativity. Etc.

TeV

[whswhs]

Originally Posted by teviet

They no longer exist, since there is no gravitational redshift.

You can get something sort of like black holes, in a weird way, from an etheric physics. Ether is considered to be a medium in which electromagnetic waves propagate. But those waves are purely transverse, with no longitudinal component. That means that ether acts not like a fluid, not even like a crystal, but as something that is to a crystal what a crystal is to a gas: a hyperrigid medium.

Well, can you create defects in that medium? Such a defect would be a perfect insulator for electromagnetic radiation.

Perhaps, in fact, the observed universe is contained in a vast sphere of ether, one that is floating through infinite space, surrounded by etheric voids. Elsewhere there may be other spheres. But unless ours collides with one (likely producing temporary liquefaction of the ether!), we can never see them, because light itself cannot cross into the void.

For instance: do nuclear reactions exist in your universe? Maybe, maybe not, or maybe there are completely different reactions in their place; the underlying mechanisms would be different. Without E=mc^2 they would not be associated with a change in the "rest mass" of the constituents. Antimatter and total conversion make no particular sense without relativity.

There might be sufficient pressure at the center of the sun to turn ether locally fluid, producing bizarre reactions.

Failing that, we're back to Kelvin: the life of the sun is limited to tens of millions of years. (Though Kelvin might have underestimated; if I recall correctly, the interior heat of the earth comes 40% from radioactive decay in the mantle, and 60% from heat of crystallization of the solid core, so the Earth could have had interior heat sources for at least hundreds of millions of years. Even so, you'd have a much younger solar system, and a much closer doom. Cue the final images of the Time Traveller's voyage.)

Bill Stoddard

[vicky_molokh]

OK, so I see at least three branches that represent directions this thread could go. As far as I understand, these are:

• Etheric physics. Interesting and weird, but very dangerous for any discoveries and science past the Nuclear stage. Also, arguably dangerous for maintaining black holes . . . and not having black holes is a bit unfun, even though they rarely affect the PCs anywhere near directly in any sort of plausible scenario.
• Preferred Frame of Reference. Allows FTL with little fuss, and optionally allows time dilation to some extent. Convenient at first sight, but arguably dangerous for Quantum-stage discoveries and science.
• Wholly Newtonian treatment of physics, including photons being 'just' particles. Neat and convenient, but probably incompatible with anything past 1900.

I'm really interested in option II. I do not care about gravitational time dilation (if black holes don't have an infinite fall time, so be it). I think velocity-based time dilation is mostly irrelevant if STL ships never reach velocities anywhere near c, while FTL ones use hyperspace or jumps, i.e. they don't actually accelerate to nor past c in the conventional sense.

[David Johnston2]

Originally Posted by vicky_molokh

Greetings, all!

Probably the easiest solution to resolving many paradoxes emerging due to FTL technologies in Space/Spaceships is to simply ditch relativity. However, this cannot pass without consequences.

...sure it can. If it doesn't it is no longer the easiest solution.