# Time Machine.

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so for example, if you drive a rocket ship at the speed of light to the sun and back, the trip will be instanteneous. It won't take distance/(speed of light) time, it will take 0 minutes.

Actually it takes over 8 minutes for light to reach us from the Sun.

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ok, i should rephrase that.

No matter how long it will take for the people on earth to see you again, for you it will feel like no time has passed. One moment you're accelerating to the speed of light, then you and your clock and the person sitting next to you are all frozen, and the next moment you're landing on earth. You would have aged 16 minutes less.

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It reminds me a episode of Andromeda where they met a old earth ship... for the crew only some years had passed by.. 10 or so. tho they were lost and sent out to explore thousand years ago(if i remember right).

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a rocket with a large octanitrocubane booster strapped to its back (it has the highest r.e.f.)...

although i suppose if the nozzle is 1/30 the size of a 1:1, it can go the speed of light.

explosives such as that do not make good rocket fuel.

nozzle geometries cannot make something with inertial mass travel at the speed of light, nor can they infinitely increase the energy output of a rocket engine.

you need to go learn some relativity, chemistry and some more basic physics wouldn't go amiss either.

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ok, ok, we're not all advanced physicists you know...

yeah i just picked that explosive because it has the highest detonation velocity... it's hard to say what the velocity of kerosine + lox is.

i actually agree that you can't go at the speed of light, however I think you can go at 99.999999% speed of light. Because:

say you're going in a rocket in space (for no friction or air resistance). Accelerating to a certain point would be simple. However, as you approach the speed of light, the reaction in your rocket slows dow due to time dilation. If you could go at the speed of light, so the kerosene and oxygen would stop reacting. The temperature of your whole ship would drop to 0K. But its ok, humans on board will not even feel the temperature drop or anything strange. To them, the kerosene and oxygen are still reacting.

Here's a sketch below. As you try to accelerate to the speed of light, the rate at which you accelerate approaches to zero. which is why you would need infinite energy to get to speed of light. But it will be simple to get to 99.99% speed of light. The flight airspeed record is almost 1/three million the speed of light.

Edited by max.yevs

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Do you know why old people run to stay young?

As they approach the speed of light, time dilates so they age slower.

Edited by max.yevs

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Do you know why old people run to stay young?

To stay fit.

As they approach the speed of light, time dilates so they age slower.

You can't run at even close to the speed of light, nor fast enough that the most sensitive equipment on earth could observe relativistic effects at running speeds.

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You can't run at even close to the speed of light, nor fast enough that the most sensitive equipment on earth could observe relativistic effects at running speeds.

actually i think we can measure the effects however, you would need to run fro several days straight before we got a useful reading.

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The point being, they could run at 500 mph for their entire life, never stopping, and only add a few nanoseconds relative to someone who didn't run. Max actually couldn't be more wrong with his point.

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You know, that would mean that technically, train drivers (and pilots for the military [fast planes] and commercial companies) age slower than the regular population that stays in one location most of their lives.

The effect, however, is minuscule.

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The point being, they could run at 500 mph for their entire life, never stopping, and only add a few nanoseconds relative to someone who didn't run.

Must disagree here. 500mph is .000074% the speed of light.

After 50 years of non-stop running, they would have aged 19.59 minutes less.

Maybe people who don't want to age should sleep in a rotor thing that spins them around at the speed of light.

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Must disagree here. 500mph is .000074% the speed of light.

After 50 years of non-stop running, they would have aged 19.59 minutes less.

I believe the effect is exponential (which means that your calculation is wrong) but I'm not sure. Even if that calculation is right, though, would those 19:59 minutes be worth the non-stop driving at 500mph ?

Merged post follows:

Consecutive posts merged

Maybe people who don't want to age should sleep in a rotor thing that spins them around at the speed of light.

As was pointed out multiple times in this thread already, anything traveling at the speed of light is only possible if you're energy. Which would make this argument moot.

On top of that, even if, theoretically, someone travels really-really-fast, the time relative to stationary object moves faster, but the moving-person experiences slower time, which means his CONSCIOUSNESS, TOO, is slowed down.

Do you know of the "twin" paradox, max? If one of the twins stays on earth and the other takes a trip at close to the speed of light, then for the traveling twin time slows down - he experiences an hour of time while the stationary twin experiences two years (i didn't calculate, I'm just throwing numbers to make a point).

The traveling twin experiences dilated time: he doesn't get younger, his entire reality is slowed, including his consciousness and thought process. He is, essentially, *missing out* on that time that passes to his stationary twin.

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Your math is wrong. Driving at 500 mph will cause you to age less than half a millisecond less then your stationary counterpart. Even if it increased your lifetime by a hundred years, it would not be worthwhile as you would simply be living your life in slow motion, and would have a lot of trouble keeping up with progress. Not to mention the risk of premature death due to crashing.

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oh, ok, my math is wrong...and those are some very complicated equations...if only speed to time dilation was a linear equation.

yeah i have heard the twin paradox in fact here's a link, but the other twin wouldnt know he's slowed down, he's only slowed down in relation to the stationary twin, right?

p.s. wow, physics threads are much more active then chemistry ones

Edited by max.yevs

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oh, ok, my math is wrong...and those are some very complicated equations...if only speed to time dilation was a linear equation.

yeah i have heard the twin paradox in fact here's a link, but the other twin wouldnt know he's slowed down, he's only slowed down in relation to the stationary twin, right?

Read my post again: The moving twin will experience dilated time, which means he is "slow motion" to *EVERYTHING ELSE that is stationary.

In short, you can say that he's aging slower but he's also doing *everything else* slower. So he is *missing out* on the time moving to the stationary twin. He cannot "experience it" the same, because he is moving much faster.

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right, but he wouldn't know he is slowed down... he wouldn't be like why are my hands moving so slowly...

he'll just see that the world around him is moving super fast.

and am i right by the way that as he approaches speed of light, temperature of everything in his ship would approach 0 Kelvin?

Edited by max.yevs

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max, he wouldn't even realise his hands move slowly because his entire being is existing slower. His brain is slower. His eyes are slower. His everything is slower.

Relative to him, his time goes on as usual.

Relative to the stationary people, time goes on as usual.

Relative to each other, time is different.

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Like make a (fictional) field in which time is lets say slowed down by 10 times. You can see through the filed.

Inside you have a clock and outside there is a clock(stopwatch) too.

Lets look at that clock from outside the field for 10 hours.

What do you see in 10 hours? Only that clock inside shows 1 hour have passed by.

Now monitor that clock from inside for 10 hours.

You see that after 10 hours, clock outside - 100 hours have passed by.

Still, even if you are inside or outside that field, physically you feel no difference xept seeing through field how everything moves faster or slower.

We know that we can slow down time this way - what about speeding it up? Like generating a field(fictional again) around you when u got shot by a gun. You see the bullet outside field, frozen and you can move away from its path and resume normal time?

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nah, i get it...if anything, its only strange once you're at the speed of light...

for example say in your rocket, kerosene and liquid oxygen are reacting. Anyone who looks from outside the rocket will see that the molecules are not moving and thus not reacting. No kerosene is being burned.

But from inside the ship, kerosene and oxygen are reacting at normal rate. Let's say at that rate, 1 gallon of kerosene is burned an hour.

So after an hour, how much kerosene is burned?

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nah, i get it...if anything, its only strange once you're at the speed of light...

for example say in your rocket, kerosene and liquid oxygen are reacting. Anyone who looks from outside the rocket will see that the molecules are not moving and thus not reacting. No kerosene is being burned.

Theoretically, if you have a camera inside the *moving* rocket and you're looking at the feed on the ground, then, THEORETICALLY, you will see everything moving very slowly, but it *will* react. Just very. very. slowly.

You cannot move in the speed of light, because you are made of matter, and the only thing that can move in the speed of light is energy.

Time, therefore, does not STOP. It moves. Just very slowly.

If you look at a monitor in your moving rocket which is feeding you the images of the outside *stationary* world, then you will probably - theoretically - see that feed moving very quickly.

You, however, as the moving object, will think that *you* are normal and everything else is just insanely fast.

We, the static object, will think that we are normal and you are insanely slow.

You won't notice it. We won't notice it. We will just notice the time dilation relative to one another.

So after an hour, how much kerosene is burned?

An hour relative to who?

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You cannot move in the speed of light, because you are made of matter, and the only thing that can move in the speed of light is energy.
Yeah, i realize that- because it will take an infinite amount of energy, post #30 i believe, but you can travel at (0.99)$^{10000000}$ the speed of light, which, if you round it, is the speed of light.

An hour relative to who?

ok, that was a smart line.

p.s. i seriously got to stop posting on this thread

p.p.s. sorry i must have missed what are your main points, twice.

p.p.p.s. i like to be the last one to respond, but apparently that's not going to happen. but i think i got the main idea...

Edited by max.yevs

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Yeah, i realize that- because it will take an infinite amount of energy, post #30 i believe, but you can travel at (0.99)$^{10000000}$ the speed of light, which, if you round it, is the speed of light.

No, it's not, it's $0.99^{10000000}$ the speed of light. But fine, it's close enough - still my point holds: Time does not STOP. It's still "running", just very slowly. You are again ignoring the main point in my post and relating only to points that you think will support your own premise.

ok, that was a smart line.

Maybe because it is a necessary detail to answer your question. The entire point is that time is *RELATIVE*.

You must state relative to WHAT, otherwise the question is moot.

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well for you, inside ship, 1 gallon per hour is used. For others it depends how much slower time is for you, if its 10x slower then for those in normal time it would take 1/10 of a gallon per hour.

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Yeah, i realize that- because it will take an infinite amount of energy, post #30 i believe, but you can travel at (0.99)$^{10000000}$ the speed of light, which, if you round it, is the speed of light.

Wrong again When you multiply a positive number by a positive number less than 1, you end up with a smaller number. In this case, $(0.99)^{10000000} \approx 0$. So says Google calculator.

I suppose that you meant a number with ten million 9's after the decimal. You could write that as $1-10^{-10000000}$ though your average non-geek is likely to say "Huh?"

Cheers, Mr Skeptic

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Guys, go back on topic please.

Merged post follows:

Consecutive posts merged

Posts related to google calculator were moved to their own thread in the computer science forum.

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