Stephen Hawkins Universe - Time Travel

Castiel · 26 Sep 2010 at 01:18

DavidMarq said:
You seem to miss the point, I quoted your post not the OP, it is your post that contains 99.99r which is 100

Why not just put 100?

because 99.9999999999 and so on is not 100. 100 in this case is infinite. The equation demands precision due the huge changes in the result by just one decimal place.

stulid · 26 Sep 2010 at 01:18

G-MAN2004 said:
Okay, here's a silly scenario. Let's say each twin had a calendar and a clock and both ticked off each day. When the twin gets back to earth, surely they will have ticked off the same amount of days right? Or am I being utterly stupid?

Yes, I'm not a physics person

the clocks would lose sync, see my first post in this thread about the GPS system that gains 3 billionth's of a second each day.

Philtor · 26 Sep 2010 at 01:19

stulid said:
why, theres no gravity in space to act upon your body, no G force to experience?

Fair point about the G force. Still... Einstein said it would take an infinite amount of energy to achieve the speed of light.... Not going to happen. lol !

Tefal · 26 Sep 2010 at 01:19

philtorrens said:
Hawkings might be a smart man but as I've said before all of this time travel craic is not possible given it would take an infinite amount of energy to travel at the speed of light.

That's why it's 99.9

Even to get close to it wouldn't be possible. Even if we did manage to achieve them speeds,

We've gotten particles to 99.something C and then slammed them into other particles going 99.something C the other way.

the human body could not withstand such a speed. Your organs would be mush.

That's acceleration not speed, you could accelerate at 1G for several months/years and get there fine of course once you reached that speed and stopped accelerating your artificial gravity would go

Tefal · 26 Sep 2010 at 01:20

stulid said:
why, theres no gravity in space to act upon your body, no G force to experience?

G force due to acceleration still exists, but you don't have to accelerate that quickly.

Castiel · 26 Sep 2010 at 01:22

G-MAN2004 said:
Okay, here's a silly scenario. Let's say each twin had a calendar and a clock and both ticked off each day. When the twin gets back to earth, surely they will have ticked off the same amount of days right? Or am I being utterly stupid?

Yes, I'm not a physics person

No, ship time would be halved due to time dilation.

Angilion · 26 Sep 2010 at 01:22

Castiel said:
90 million would give 8 seconds at c. I worked it out at around 0.004seconds per year for mach 2, I cant find the reference online.

I'll keep looking.

Commercial airline pilots don't fly at mach 2 all the time, let alone c. I was going on 500mph.

Biohazard · 26 Sep 2010 at 01:22

stulid said:
the clocks would lose sync, see my first post in this thread about the GPS system that gains 3 billionth's of a second each day.

oh noes!

DavidMarq · 26 Sep 2010 at 01:22

Castiel said:
because 99.9999999999 and so on is not 100. 100 in this case is infinite. The equation demands precision due the huge changes in the result by just one decimal place.

But 99.99r is exactly 100...

Can't be any more precise than that :confused:

Castiel · 26 Sep 2010 at 01:24

DavidMarq said:
But 99.99r is exactly 100...

Can't be any more precise than that

No, 99.99r as a percentage of 100 cannot be 100.

stulid · 26 Sep 2010 at 01:24

Tefal said:
G force due to acceleration still exists, but you don't have to accelerate that quickly.

the clues in the name!! gravitational force, no gravity in space(ok a tiny little wee bit)

Castiel · 26 Sep 2010 at 01:30

stulid said:
the clues in the name!! gravitational force, no gravity in space(ok a tiny little wee bit)

http://en.wikipedia.org/wiki/Gravitational_constant

acceleration of a mass the size of a starship would cause inertia and g forces.

Biohazard · 26 Sep 2010 at 01:31

yeah man didn't you watch apollo 13, they get shoved back a bit when they boost. that's why they sit etc

bigjimmyauk · 26 Sep 2010 at 01:31

so in star trek why is it when they go back home everyone is the same age surely voyagers crew would be only 4-5 years old but considering voyager spent 3 months at warp 9.6 (205 trillion KMH)(1.9x light speed) surely everyone on earth would be years older yet when they returned they looked the same lol

this is all according to my star trek fact files collection and they're warp speed explanation

i'll just stick to star trek theory it's easier to understand

AiiR · 26 Sep 2010 at 01:33

Found it really interesting, I just don't understand going that fast in space. Say we did manage to reach those speeds one day, how would we manoeuvre through space debris such as asteroids?

stulid · 26 Sep 2010 at 01:34

Castiel said:
http://en.wikipedia.org/wiki/Gravitational_constant

acceleration of a mass the size of a starship would cause inertia and g forces.

only to the ship, not the bodies inside, they are along for the ride, if the ship stops moving suddenly, the bodies are still moving forward at the same speed, so need seat belts.

thats why astronauts dont experience black outs from G like a fighter pilot, or need a G suit.

rypt · 26 Sep 2010 at 01:34

bigjimmyauk said:
so in star trek why is it when they go back home everyone is the same age surely voyagers crew would be only 4-5 years old but considering voyager spent 3 months at warp 9.6 (205 trillion KMH)(1.9x light speed) surely everyone on earth would be years older yet when they returned they looked the same lol

this is all according to my star trek fact files collection and they're warp speed explanation

i'll just stick to star trek theory it's easier to understand

Don't they bend space/time rather than accelerate the ship though?

Castiel · 26 Sep 2010 at 01:34

bigjimmyauk said:
so in star trek why is it when they go back home everyone is the same age surely voyagers crew would be only 4-5 years old but considering voyager spent 3 months at warp 9.6 (205 trillion KMH)(1.9x light speed) surely everyone on earth would be years older yet when they returned they looked the same lol

i'll just stick to star trek theory it's easier to understand

Startrek invented 'subspace' the 'warp field' envelopes the ship and then moves the ship through subspace thus fictionally negating the paradoxes. Much like folding the space between two points on a paper map.

Philtor · 26 Sep 2010 at 01:35

Castiel said:
http://en.wikipedia.org/wiki/Gravitational_constant

acceleration of a mass the size of a starship would cause inertia and g forces.

So this means at the speed of light our organs would turn to mush then? That's what I always thought.

Tefal · 26 Sep 2010 at 01:35

stulid said:
the clues in the name!! gravitational force,

Actually it's just a term to put how much force you're under from acceleration into perspective.