

What the world would look like if light traveled slowly (interactive simulation) - idlewords
http://realtimerelativity.org/downloads.html 

======
derefr
Light travels "as fast as it can." If light travelled slowly, then, by the
momentum equation of special relativity, we'd still ramp our energy limits
long before we saw this sort of stuff. In fact, if things took so much more
energy to move about, macro-scale creatures such as ourselves would probably
not have developed.

I think the author meant "what if light travelled at only a fraction of the
speed it physically could?" which is a much more ridiculous question, but with
even more interesting implications, especially if you don't also scale down
the speed of gravitational transmission et all to match.

~~~
nopassrecover
I remember looking into the question of gravitation transmission before. As
far as I could amatueurly determine, gravitational transmission is an
unanswered question. This is to say, if the sun "dissapeared" would the Earth
feel it straight away (because spacetime had been altered) or would it take as
long as the time for light to reach us because gravitrons (if they exist)
could only travel as fast as the speed of light?

I'm aware of the whole limit on information transmission so I assume the
latter, but I thought it was still unanswered.

~~~
derefr
I think the real problem with that question is deciding exactly what you mean
by "disappear." If you blow the sun up, it still has all its mass, it's just
spreading apart, and the effect this has on Earth can be graphed continuously.
Likewise if you just move it somewhere else really fast (because you can't
move it faster-than-light.) If you convert it completely into energy, by the
mass-energy equation, it _still_ has all its mass.

Thinking about gravity becomes a lot simpler when you realize that every one
of those particles of the Sun is quantum-entangled with all the particles of
the Earth. If you want to "remove" the Sun, you have to decide what that means
for the decoherence of the configuration subspace consisting of (what was
previously) Sun + Earth.

Configurations only evolve toward more definite subsections of themselves, not
completely "new," remote amplitudes. Also, as far as we can tell, decoherence
is computable from the completely _local_ neighborhood of the amplitude-mass
in question. Thus, gravitational transmission has to take _some_ amount of
time, in the same way that one domino can't knock down another across the room
instead of going through the dominos in-between.

The interesting thing is that _some_ of the particles of the Earth
(analogously, the intermediate dominos) would be immediately affected—but it
would take Au/C before enough of them were affected that that decoherence
would become _detectable_.

~~~
nopassrecover
Wait so gravity is quantum entanglement?

I've never been given that view before. If I understand you correctly, gravity
does have an effect faster than the speed of light but there is no detectable
effect faster than the speed of light?

------
chrischen
I think the purpose of this application is to teach the theory of relativity
and show what it would feel like _if_ matter (the space ship) could travel at
the speed of light. Of course the only way to do this is if the speed of light
was slower, and not the max speed of the universe. I guess you'll get to see
how buildings will compress, and time will slow down.

I just happened to be on Windows 7 64 bit on boot camp on my mac and it didn't
work. Required some dll file called d3dx9_37.dll. So I downloaded it and put
it into windows system folder and it ran.

It's pretty trippy. It's like at 3d game where you control a spacecraft except
when you start moving forward it's like you're on drugs.

------
RiderOfGiraffes
It's Mr Tompkins!

<http://en.wikipedia.org/wiki/Mr_Tompkins>

------
dennisgorelik
Why does it require installation? Do they know that YouTube is available for
years already?

~~~
idlewords
It's an interactive simulation, like the title says. You can fly around a
cityscape at speeds approaching c.

------
brtzsnr
No linux version?

~~~
jws
Maybe just as well. On the Mac version it seizes the cursor so you can't get
to the menu bar and won't quit with Command-Q despite flashing the menu to say
"Yeah, I know you want out. Piss on you.

If the UI is that impolite on the machine known as the "fairy princess of user
interface", then on Linux it would probably leave smelly food in your fridge
and reorder your DVD collection.

~~~
mynameishere
dll errors under windows. Oh well. Let's hear it for shit engineering.

