[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.

[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

[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.

[Anthony]

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.

The easiest solution is to introduce a privileged reference frame (which is used by FTL) and leaving all other equations the same. This violates the principle of locality, so it's effectively ditching relativity, but it does so in a fairly innocuous way.

[malloyd]

Originally Posted by vicky_molokh

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.

I'd just like to point out here there is absolutely no reason to feel you need to patch them. You do *not* need to work out all the details of an alternate physics any more than you need to completely understand how the details of our physics generate all the phenomena in the universe (which for many of the interesting complex phenomena *nobody* can quite do yet). It's perfectly acceptable to simply declare certain things happen. You may or may not choose to declare physicists in the setting understand why, but even if you do, you need not actually provide the reason.

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

In the usual scheme of ditching relativity, the preferred frame, time is an absolute, so no, doesn't happen.

[*]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?

Doppler (speed based) shifting is an entirely classical effect, so no changes. Gravitational red/blue shifting merely requires the carriers of light to have a potential energy. Under any physics where they have a momentum you'd porbably expect that. Though the constants may change, one of the classic tests of relativity is the gravitational bending of light by the sun being twice the classical prediction. And IIRC relativistic photons also have twice the momentum as they classically should.

[*]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?

If you need them (and there's no particular reason why you should - they are after all still undetected in *our* universe, so they aren't particularly critical to the physics of anything likely to matter to PCs), just fix their propagation velocity. If you are using an ether then c relative to it makes decent sense, but it's not difficult to imagine that it might be 2c or 1/2 c or c/sqrt(2) or something. Infinity isn't ever an option though, that's not a *wave*.

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

Except for stuff in a tight orbit around a black hole, gravitational radiation produces no measurable orbital decay in the first place - collide with an extra atom or two and you've probably lost more energy that gravitational radiation would sap from your orbit in a year. So really, no change in anything that's going to matter.

[*]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?

Classical photons arguably still lose energy climbing against gravity, not velocity, so the basic reasoning would be unchanged - though again the constants will differ.

[David Johnston2]

Originally Posted by malloyd

In the usual scheme of ditching relativity, the preferred frame, time is an absolute, so no, doesn't happen..

In the usual scheme of ditching relativity, time is only an absolute in "hyperspace" or whatever so it still happens if you accelerate conventionally.

[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.