Wizards vs fighters, bombers, and attack aircraft.

[Username17]

But even if you were really concerned with preventing time travel and you insisted on teleportation being literally instant instead of effectively instant as it is canonically, it still wouldn't be an issue. Within the boundaries of the solar system, there just isn't space to build up enough of a time differential to get even a whole second or even a quarter second into the past.

I just checked Wikipedia, but it says one AU is ~149.5 billion meters and the speed of light is ~299 million meters per second. (I rounded both down.)

(149,500 Mm) / (299 Mm/s) = 500 seconds from the Sun to the Earth

(Yes, it's an even result. It surprised me too.)

8 minutes * 60 seconds/minute = 480 seconds

So, there's more than eight light-minutes from the Sun to the Earth on average.

That doesn't mean what you think it means. The fact that it takes 8 minutes for light to travel from the Sun to the Earth doesn't mean that you can send a message backwards in time by 8 minutes if you send it instantaneously. Time Travel of information only occurs when your reference frames are progressing at different rates of speed so that your eight minutes are over before mine are. Then you can receive the information before I do and then send it to me directly and have the information come to me from "the future".

The fact that it takes eight minutes for light to travel from the Sun to the Earth is actually bad for time travel enthusiasts, because the only way you're going to get future messages to make a fuck bit of difference is to send them back to their point of origin. And that means that if your relativistic partner is eight light minutes away, you lose eight fucking minutes sending the future message back to its senders. So unless you've managed to send it more than 8 minutes into the past, your message from the future is going to be from the past again by the time you get it back.

The actual time difference builds up over time as you travel at high velocity. Eventually you'd be able to to build up more than 8 minutes of difference by zooming around the sun at double speed. But in this case eventually is a long time. Like, literally decades.

-Username17

[nockermensch]

I won't try to read this whole thread, but on the subject of fantasy land vs. real world, does anybody else here also knows The Salvation War? (link is to the TVTropes page which contains links for the stories).

The TL;DR; is "Humanity vs. the christian hell and heaven's forces. Humanity wins."

Despite the promise of awesome a premise like that could deliver, I didn't like it. I'm not a christian or even a religious person, but that story was one of the moments that made me feel shame for my team, in a "if we need to show the bad guys like THAT for us to be awesome, then we're not awesome" way.

The author goes to great lengths to suck the military industry's cock and to give huge idiot balls pretty much to all the devils and angels. Also becomes a Rome fanfic a bit after the mid of book one, without warning, which is very jarring.

This rant probably should fit better in the "moments a piece of entertainment completely lost you" thread in MPSIMS forum, but since I learned about those books by reading some other "Real vs. Fantastic" thread, I feel placing this here as a warning would also work.

[quanta]

First of all: we don't live in a causal universe. People who try to rescue causality are forced to invent "secret, undetectable causes that are impossible to predict or prevent that operate in all observable ways like random events" in order to explain quantum movement and radioactive decay.

What? No. Maybe philosophers use causality with that meaning and assume quantum physics violates causality but most physicists don't. Random and causal aren't even really opposed things in physics terminology. Pretty much the only thing causality means to physicists is that information cannot travel backward in time. And as far as we know information does not travel backward in time. Physicists generally revile theories that allow for propagation of information backwards through time. To the best of our knowledge, our universe is causal (as a physicist would mean by causal).

Now quantum physics doesn't look very deterministic, but you can come up with a pilot-wave explanation that's deterministic and obeys the same math as the mystical Niels Bohr interpretation of quantum. You can also just accept that maybe quantum mechanics isn't fundamental so the fact that its predictions are probabilities doesn't actually mean anything about the fundamental nature of the universe. And well... that's a totally reasonable position to take.

But more seriously, if D&D universe linked up with our universe, all it would really mean is that our grasp of physics was wrong. Maybe teleportation happens by creating spacetime wormholes! Maybe it really only is effectively instantaneous. Maybe D&D universe obeys Newtonian physics and you can totally build xia's 5 body configuration there and accelerate object to infinite speed in finite time in the magic universe. All we know is that D&D universe has teleportation and seems to be causal.