Hawking Says Time-Travel is Possible.

[Astute One]

hawking hasnt submitted a new theory and einsteins calculations have already been confirmed experimentally

It is also interesting to note that the article states that Hawking said one day would be like a year. 1/70th is not one day in a year.

The article also states that he said humans can travel millions of years into the future. Now, how can a human travel a million years into the future even with a life span of 100 years? According to your calculation, if a human left at age 1 day, he could only travel 7000 years into the future in 100 years.

The article also says that he said: as humans travel close to the speed of light, they would be skipping years (thats years plural) on a daily basis. This also contradicts your calculations.

So what the heck is going on. There is even more to it. The speed quoted in the article is at 0.98 C which yeilds a number that translates into even less time dilation.

If this article is false, it should be retracted with in a few days. If it is not. Something big is on the horizon.

Because if Einstein was wrong, the situation that I state above could be more on target than the current theories, and faster than light travel may be possible. This article sure indicates that it is.

Some of Einsteins work appears to be proven, but only until another measuring devices is made that proves him wrong. This may have just happened with the LHC.

I guess we wait and see.

[Copasetic]

Yes, that is what I get also. Here is the kicker. The article says:

"When we accelerate tiny particles to 99.99 per cent of the sped of light in the Large Hadron Collider at Cern in Geneva, the time they experience passes at one-seventhousandth of the rate it does for us," Prof Cox said.

Now either this is a misprint or the current theory is wrong and produces a value two orders of magnitude off.

Now, do you see why I said we are on the edge for the books to be rewritten?

Can this be why Hawking is changing his tune?

No, the math is fine, your doing it incorrectly.

Consider this example to understand. Say I had a number, any number, let's say 50. And I wanted to increase said number by 20%, how do I do that?

Solve the algebraic expression;

(.2*50)+50=X

10+50=X

X=60

So we have increased 50, by 20% which is not the same as the numerical factor of 20%.

To see the numerical factor of 20% we take 60/50=1.2

So by taking 50*1.2 we also increase by 20%.

So the numerical factor 70.7 is not how you are viewing it, it is a numerical factor not a percent.

Edit:

In other words, increasing by 100% is the same as multiplying by a factor of 2. 1000% by 11. 7000% by 71.

Edited May 4, 2010 by Copasetic

[Astute One]

Correct: The time standard, a second, is defined as the decay from one state to another for a caesium 133 atom. Which will be the same throughout all frames of reference.

That doesn't make sense. If you send a cesium clock into space at high velocity and bring it back, it should be off when compared to a clock on Earth. Therefore it is not the same through all reference frames, but only the frame it is in.

You must mean when viewed from the reference frame the clock is in, otherwise, I do not believe you.

http://www.time.com/time/magazine/article/0,9171,900146,00.html

Above link case in point. The pulsars reference frame indicates the Earth is experiencing time dilation as it travels through space-time and time lags in January when compared to the pulsars reference frame because of this effect.

[Alien Being]

The time travel he is talking about is nothing new. Its just time dilation. He doesnt say it is possible to travel back in time.

he definitely does not say spaceships will be able to go faster than the speed of light. In his book A Brief History of Time he stresses that it is impossible. he says they will be able to go near the speed of light, like 650 million miles per hour. light travels at 671 million miles per hour

Time cant flow backwards because the nuclear forces are non reversable (not time symmetrical).

[Copasetic]

That doesn't make sense. If you send a cesium clock into space at high velocity and bring it back, it should be off when compared to a clock on Earth. Therefore it is not the same through all reference frames, but only the frame it is in.

You must mean when viewed from the reference frame the clock is in, otherwise, I do not believe you.

http://www.time.com/time/magazine/article/0,9171,900146,00.html

Above link case in point. The pulsars reference frame indicates the Earth is experiencing time dilation as it travels through space-time and time lags in January when compared to the pulsars reference frame because of this effect.

Right, That's what I said. The decay, like the speed of light, is the same in every reference frame-Meaning in each frame it will always be 9,192,631,770 periods of decay. Not across reference frames.

Edited May 5, 2010 by Copasetic

[Copasetic]

Time cant flow backwards because the nuclear forces are non reversable (not time symmetrical).

Time doesn't flow. It just is. Its like space, space doesn't flow, it just is.

We pass, so time 'passing' becomes and artifact of our conciseness passing.

Edit:

I see where you are going with this though. You are correct in that the universe cannot return to a previous state, such would be a violation of thermodynamics. Which means, from the standpoint of a quantized unit of time, there could be no 'going back'.

By quantized I mean; Think about it like this, suppose we are a happy hydrogen atom with 1 proton and 1 electron. Our electron can absorb energy from photons and jump to higher energy levels, increasing the quantum state of the atom.

But, a photon must possess the necessary energy for the electron to jump to the next level, it can never jump in between levels.

Meaning, there exists a necessary and discrete state, a 'jump' if you will. There isn't a continuous spectrum of energy states.

Other quantities in the universe are like this. Including, theoretically of course, time. In a unified field theory, time would be quantized, meaning having a discrete, indivisible base unit.

Edited May 5, 2010 by Copasetic

[Astute One]

The speed of light is a constant regardless of reference frame. Just like a second is. Remember, the laws of physics are the same in every frame of reference possible.

That means, if one were traveling at the .99c on a train and turned on a flashlight, The light would only ever go C, never additive like Newtonian velocities. It would be cool if they did, but unfortunately physics doesn't work like that. Apply my example above to your example here.

But the laws of phyics do not appear to be the same when viewing another reference outside of one's own ref. frame.

Are you saying that the light as seen by the person who turns on the flashlight will travel at 0.01c if the flashlight and person are traveling at .99c in reference to Earth? Because if you are, c is not constant in your world, and you just changed the law of phyics for the flashlight frame of ref.

[Startraveler]

But the laws of phyics do not appear to be the same when viewing another reference outside of one's own ref. frame.

Copasetic is merely restating the first of the two postulates underlying special relativity.

[Astute One]

No, the math is fine, your doing it incorrectly.

Consider this example to understand. Say I had a number, any number, let's say 50. And I wanted to increase said number by 20%, how do I do that?

Solve the algebraic expression;

(.2*50)+50=X

10+50=X

X=60

So we have increased 50, by 20% which is not the same as the numerical factor of 20%.

To see the numerical factor of 20% we take 60/50=1.2

So by taking 50*1.2 we also increase by 20%.

So the numerical factor 70.7 is not how you are viewing it, it is a numerical factor not a percent.

Edit:

In other words, increasing by 100% is the same as multiplying by a factor of 2. 1000% by 11. 7000% by 71.

The article says 1/7000th. This has nothing to do with what you state above. It is two orders of magnitude difference. 1/70 .vs. 1/7000

[Copasetic]

But the laws of phyics do not appear to be the same when viewing another reference outside of one's own ref. frame.

Are you saying that the light as seen by the person who turns on the flashlight will travel at 0.01c if the flashlight and person are traveling at .99c in reference to Earth? Because if you are, c is not constant in your world, and you just changed the law of phyics for the flashlight frame of ref.

Right, because the frame of reference is relative to the observe. But the rules within the frame are the same throughout the universe.

No, if a person traveling at .99c were to turn on a flashlight, they would observe the light traveling at c.

Copasetic is merely restating the first of the two postulates underlying special relativity.

1. First postulate (principle of relativity)

The laws by which the states of physical systems undergo change are not affected, whether these changes of state be referred to the one or the other of two systems of coordinates in uniform translatory motion.

2. Second postulate (invariance of c)

As measured in any inertial frame of reference, light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body.

link

[Copasetic]

The article says 1/7000th. This has nothing to do with what you state above. It is two orders of magnitude difference. 1/70 .vs. 1/7000

No your not understanding the math still. If time is passing 20% faster in someone else's frame of reference than in ours its a numerical factor of 1.2. If its passing 7000% faster (or ours is 7000% slower) its a numerical factor of 71.

So 70.7 is just under 7000%

[Astute One]

No your not understanding the math still. If time is passing 20% faster in someone else's frame of reference than in ours its a numerical factor of 1.2. If its passing 7000% faster (or ours is 7000% slower) its a numerical factor of 71.

So 70.7 is just under 7000%

I do understand the math. Been doing it at very long time.

We are not talking percents. No one has said percent. The article doesn't read 1/7000%. You are adding something that is not there.

I understand the math, but it isn't appropriate to place a percent symbol where one does not exist. If the article said time was passing 7000% faster I would agree with you. BUT THIS IS NOT WHAT THE ARTICLE STATES.

It could be a miscommunication in the article, but look at all the other stuff I mention in post#51.

Why does this article quote Hawking stating things that are a mathematical impossiblity with a 71x time dilation factor?

Either the article is full of miss quotes or there is something that you and I do not yet understand. There is something FISHY here.

I value your opinion, so take a look at post #51 and read the article again and let me know what you think.

I am sure there is a logical explanation, but I haven't seen it yet.

Edited May 5, 2010 by Astute One

[ranrod]

Here's one thing that I don't have clear: In the train example where the people on the train traveling at .9999c experience 1 week, but when they come to a stop find that 100 years have passed for everyone else: How many times did each side (people on the train and observers in the train station) see the train orbit the earth?

If both count the same number of orbits, for example, the people on the train counted a million orbits and a guy on the train station also counts a million orbits, then the guy on the train station will see a much slower moving train (1,000,000 orbits over a period of 100 years, instead of 1,000,000 orbits in a week). So the guy on the train station perceives the train moving 7000x slower than it is? It seems weird that something would be traveling nearly the speed of light, but when we measure it, we get 7000x slower.

If they count different orbits, then there's a bug in the universe. That'd be even weirder.

PS: does anyone have a link to follow as to why entanglement doesn't break the light-speed limit?

PSS: I thought inflation exceeded the speed of light at some point. Am I mis-remembering? No rules for how fast something moves in the nothingness outside of space-time, right?

[Drj312]

Here's one thing that I don't have clear: In the train example where the people on the train traveling at .9999c experience 1 week, but when they come to a stop find that 100 years have passed for everyone else: How many times did each side (people on the train and observers in the train station) see the train orbit the earth?

If both count the same number of orbits, for example, the people on the train counted a million orbits and a guy on the train station also counts a million orbits, then the guy on the train station will see a much slower moving train (1,000,000 orbits over a period of 100 years, instead of 1,000,000 orbits in a week). So the guy on the train station perceives the train moving 7000x slower than it is? It seems weird that something would be traveling nearly the speed of light, but when we measure it, we get 7000x slower.

If they count different orbits, then there's a bug in the universe. That'd be even weirder.

PS: does anyone have a link to follow as to why entanglement doesn't break the light-speed limit?

PSS: I thought inflation exceeded the speed of light at some point. Am I mis-remembering? No rules for how fast something moves in the nothingness outside of space-time, right?

im thinking over the train thing right now. interesting but i know there is something im missing.

you can read about quantum entanglement in Fabric of the Cosmos by Brian Greene. He explicitly states that it doesnt break the speed limit.

Inflation refers to the expansion of space. Nothing is traveling faster than light. All points of space are expanding but no matter is moving.

here we go: one other factor in the train question is length contraction due to velocity. the faster you go, the more you contract. that could be what accounts for the problem

Edited May 5, 2010 by Drj312

[Astute One]

Here's one thing that I don't have clear: In the train example where the people on the train traveling at .9999c experience 1 week, but when they come to a stop find that 100 years have passed for everyone else: How many times did each side (people on the train and observers in the train station) see the train orbit the earth?

If both count the same number of orbits, for example, the people on the train counted a million orbits and a guy on the train station also counts a million orbits, then the guy on the train station will see a much slower moving train (1,000,000 orbits over a period of 100 years, instead of 1,000,000 orbits in a week). So the guy on the train station perceives the train moving 7000x slower than it is? It seems weird that something would be traveling nearly the speed of light, but when we measure it, we get 7000x slower.

If they count different orbits, then there's a bug in the universe. That'd be even weirder.

PS: does anyone have a link to follow as to why entanglement doesn't break the light-speed limit?

PSS: I thought inflation exceeded the speed of light at some point. Am I mis-remembering? No rules for how fast something moves in the nothingness outside of space-time, right?

You are grasping the concept that others are not.

If the same number of orbits are counted, and the people on the space train experience less time than those on earth as compared to the earth ref. frame, the space train will calculate a slower speed. Then they will turn on their flashlight, point the beam in front of them, turn off the flashlight, and then accelerate to catch the flashlight beam, but they will never catch it because as the accelerate the same effect will be amplified.

Then those on Earth will obeserve them to the point that the space train passes the speed of light as observed from Earth. At this point, the space train will no longer be observable because it is out running light as viewed from Earth. This is similar to why a jet pilot going faster than sound cannot hear anything outside behind him and similar to why we cannot see past the event horizon in a black hole. The light just isn't there for us to observe it.

I think Hawking has known this, but he has been politically correct and quite for his career so the rest who do not understand will not think him a kook. Now that the LHC data shows that Eistein may be wrong and the dilation formulas may be incorrect, Hawking is coming out and expressing what he really understands. This is why he says man will be able to time travel millions of years into the future someday.

He knows that the 71x time dilation at 0.9999C velocity is not correct because this translates to only 7100 years of possible time travel in a 100 year lifespan. Even at 0.9999 c and the reported dilation factor of 7000x, a person can only travel 700,000 years into the future. This is still short of millions of years like Hawking says. Now to the observer on Earth, not only will time dilation happen, but distance dilation will happen as well, and this will cause the distance to shrink to the Earth observer; which will cause the space train to appear to go warp speed and disappear just like on Star Trek.

Are you following me?

So nothing ever travels faster than light in it's own reference frame. This is why we see light coming at us at the same speed from everywhere because we are all in the same reference frame. But if we move the entire reference frame, ie warp drive, going faster than light in reference to another ref. frame may be possible.

If we were at a distant quasar looking back at us from light years away, we would see light moving at the speed of light as well even if we were traveling at near the speed of light away from the Earth. Check out this new stuff about quasars by Hawking.

http://news.discovery.com/space/no-time-dilation-for-distant-quasars.html

This is going to turn the scientific world upside down if the article is factual in quoting Hawking. If it is not factual, then I fried my brain for nothing, and this thread has been a waste of time. Hey, its all relative.

Edited May 5, 2010 by Astute One

[Drj312]

You are grasping the concept that others are not.

If the same number of orbits are counted, and the people on the space train experience less time than those on earth as compared to the earth ref. frame, the space train will calculate a slower speed. Then they will turn on their flashlight, point the beam in front of them, turn off the flashlight, and then accelerate to catch the flashlight beam, but they will never catch it because as the accelerate the same effect will be amplified.

Then those on Earth will obeserve them to the point that the space train passes the speed of light as observed from Earth. At this point, the space train will no longer be observable because it is out running light as viewed from Earth. This is similar to why a jet pilot going faster than sound cannot hear anything outside behind him and similar to why we cannot see past the event horizon in a black hole. The light just isn't there for us to observe it.

I think Hawking has known this, but he has been politically correct and quite for his career so the rest who do not understand will not think him a kook. Now that the LHC data shows that Eistein may be wrong and the dilation formulas may be incorrect, Hawking is coming out and expressing what he really understands. This is why he says man will be able to time travel millions of years into the future someday.

He knows that the 71x time dilation at 0.9999C velocity is not correct because this translates to only 7100 years of possible time travel in a 100 year lifespan. Even at 0.9999 c and the reported dilation factor of 7000x, a person can only travel 700,000 years into the future. This is still short of millions of years like Hawking says. Now to the observer on Earth, not only will time dilation happen, but distance dilation will happen as well, and this will cause the distance to shrink to the Earth observer; which will cause the space train to appear to go warp speed and disappear just like on Star Trek.

Are you following me?

This is going to turn the scientific world upside down if the article is factual in quoting Hawking. If it is not factual, then I fried my brain for nothing, and this thread has been a waste of time. Hey, its all relative.

youre not understanding this. you can never catch up to a beam of light. even if im going .9999c, light is still traveling away from me at c. it doesnt make sense at first but eventually it will, and the math proves it. hawking has no problem presenting ridiculous things. he had the guts to say that black holes evaporated. he would have said something about this a long time ago if he discovered something. the space train will not calculate a lower speed. what youre saying is simply wrong

also, how would the LHC prove him wrong? how would they know how far the particles traveled in time? did they put a clock on them? no. they did the math using einsteins equations

Edited May 5, 2010 by Drj312

[Karlis]

Here is an extract from an article on “Mail Online”

How to build a time machine

By STEPHEN HAWKING

Last updated at 10:08 AM on 3rd May 2010

http://www.dailymail.co.uk/home/moslive/article-1269288/STEPHEN-HAWKING-How-build-time-machine.html#ixzz0n1qq2CWl

~~~ .... Any kind of time travel to the past through wormholes or any other method is probably impossible, otherwise paradoxes would occur. So sadly, it looks like time travel to the past is never going to happen. A disappointment for dinosaur hunters and a relief for historians.

But the story's not over yet. This doesn't make all time travel impossible. I do believe in time travel. Time travel to the future. Time flows like a river and it seems as if each of us is carried relentlessly along by time's current. But time is like a river in another way. It flows at diff erent speeds in diff erent places and that is the key to travelling into the future. This idea was first proposed by Albert Einstein over 100 years ago. He realised that there should be places where time slows down, and others where time speeds up. He was absolutely right. And the proof is right above our heads. Up in space.

This is the Global Positioning System, or GPS. A network of satellites is in orbit around Earth. The satellites make satellite navigation possible. But they also reveal that time runs faster in space than it does down on Earth. Inside each spacecraft is a very precise clock. But despite being so accurate, they all gain around a third of a billionth of a second every day. The system has to correct for the drift, otherwise that tiny di fference would upset the whole system, causing every GPS device on Earth to go out by about six miles a day. You can just imagine the mayhem that that would cause.

The problem doesn't lie with the clocks. They run fast because time itself runs faster in space than it does down below. And the reason for this extraordinary e ffect is the mass of the Earth. Einstein realised that matter drags on time and slows it down like the slow part of a river. The heavier the object, the more it drags on time. And this startling reality is what opens the door to the possibility of time travel to the future.

Right in the centre of the Milky Way, 26,000 light years from us, lies the heaviest object in the galaxy. It is a supermassive black hole containing the mass of four million suns crushed down into a single point by its own gravity. The closer you get to the black hole, the stronger the gravity. Get really close and not even light can escape. A black hole like this one has a dramatic e ffect on time, slowing it down far more than anything else in the galaxy. That makes it a natural time machine.

I like to imagine how a spaceship might be able to take advantage of this phenomenon, by orbiting it. If a space agency were controlling the mission from Earth they'd observe that each full orbit took 16 minutes. But for the brave people on board, close to this massive object, time would be slowed down. And here the e ffect would be far more extreme than the gravitational pull of Earth. The crew's time would be slowed down by half. For every 16-minute orbit, they'd only experience eight minutes of time.

Around and around they'd go, experiencing just half the time of everyone far away from the black hole. The ship and its crew would be travelling through time. Imagine they circled the black hole for five of their years. Ten years would pass elsewhere. When they got home, everyone on Earth would have aged five years more than they had.

So a supermassive black hole is a time machine. But of course, it's not exactly practical. It has advantages over wormholes in that it doesn't provoke paradoxes. Plus it won't destroy itself in a flash of feedback. But it's pretty dangerous. It's a long way away and it doesn't even take us very far into the future. Fortunately there is another way to travel in time. And this represents our last and best hope of building a real time machine.

You just have to travel very, very fast. Much faster even than the speed required to avoid being sucked into a black hole. This is due to another strange fact about the universe. There's a cosmic speed limit, 186,000 miles per second, also known as the speed of light. Nothing can exceed that speed. It's one of the best established principles in science. Believe it or not, travelling at near the speed of light transports you to the future.

To explain why, let's dream up a science-fiction transportation system. Imagine a track that goes right around Earth, a track for a superfast train. We're going to use this imaginary train to get as close as possible to the speed of light and see how it becomes a time machine. On board are passengers with a one-way ticket to the future. The train begins to accelerate, faster and faster. Soon it's circling the Earth over and over again.

To approach the speed of light means circling the Earth pretty fast. Seven times a second. But no matter how much power the train has, it can never quite reach the speed of light, since the laws of physics forbid it. Instead, let's say it gets close, just shy of that ultimate speed. Now something extraordinary happens. Time starts flowing slowly on board relative to the rest of the world, just like near the black hole, only more so. Everything on the train is in slow motion.

This happens to protect the speed limit, and it's not hard to see why. Imagine a child running forwards up the train. Her forward speed is added to the speed of the train, so couldn't she break the speed limit simply by accident? The answer is no. The laws of nature prevent the possibility by slowing down time onboard.

Now she can't run fast enough to break the limit. Time will always slow down just enough to protect the speed limit. And from that fact comes the possibility of travelling many years into the future.

Imagine that the train left the station on January 1, 2050. It circles Earth over and over again for 100 years before finally coming to a halt on New Year's Day, 2150. The passengers will have only lived one week because time is slowed down that much inside the train. When they got out they'd find a very diff erent world from the one they'd left. In one week they'd have travelled 100 years into the future. Of course, building a train that could reach such a speed is quite impossible. But we have built something very like the train at the world's largest particle accelerator at CERN in Geneva, Switzerland.

Deep underground, in a circular tunnel 16 miles long, is a stream of trillions of tiny particles. When the power is turned on they accelerate from zero to 60,000mph in a fraction of a second. Increase the power and the particles go faster and faster, until they're whizzing around the tunnel 11,000 times a second, which is almost the speed of light. But just like the train, they never quite reach that ultimate speed. They can only get to 99.99 per cent of the limit. When that happens, they too start to travel in time. We know this because of some extremely short-lived particles, called pi-mesons. Ordinarily, they disintegrate after just 25 billionths of a second. But when they are accelerated to near-light speed they last 30 times longer.

It really is that simple. If we want to travel into the future, we just need to go fast. Really fast. And I think the only way we're ever likely to do that is by going into space. The fastest manned vehicle in history was Apollo 10. It reached 25,000mph. But to travel in time we'll have to go more than 2,000 times faster. And to do that we'd need a much bigger ship, a truly enormous machine. The ship would have to be big enough to carry a huge amount of fuel, enough to accelerate it to nearly the speed of light. Getting to just beneath the cosmic speed limit would require six whole years at full power.

The initial acceleration would be gentle because the ship would be so big and heavy. But gradually it would pick up speed and soon would be covering massive distances. In one week it would have reached the outer planets. After two years it would reach half-light speed and be far outside our solar system. Two years later it would be travelling at 90 per cent of the speed of light. Around 30 trillion miles away from Earth, and four years after launch, the ship would begin to travel in time. For every hour of time on the ship, two would pass on Earth. A similar situation to the spaceship that orbited the massive black hole.

After another two years of full thrust the ship would reach its top speed, 99 per cent of the speed of light. At this speed, a single day on board is a whole year of Earth time. Our ship would be truly flying into the future.

The slowing of time has another benefit. It means we could, in theory, travel extraordinary distances within one lifetime. A trip to the edge of the galaxy would take just 80 years. But the real wonder of our journey is that it reveals just how strange the universe is. It's a universe where time runs at different rates in different places. Where tiny wormholes exist all around us. And where, ultimately, we might use our understanding of physics to become true voyagers through the fourth dimension.

Source to the article

[ranrod]

Here's the next question (I apologize for beating the train example to death):

Say I am a passenger in the train going at 0.9999c, and from the back of the train I turn on a hand-held laser pointed at the front of the train (this example is used in the Hawking program using a little girl), does the laser beam slow down, or the whole train slow down to accomodate? (so that c is not exceeded) In the show, they showed the little girl moving in slow motion, but if I were in the train, I wouldn't see her, or my hand-held laser slow down, right? If instead, the whole train slows down to accommodate my hand-held laser, that would be equally weird - a whole train slows down because I turned on a laser? Both possibilities sound wrong to me.

[Astute One]

youre not understanding this. you can never catch up to a beam of light. even if im going .9999c, light is still traveling away from me at c. it doesnt make sense at first but eventually it will, and the math proves it. hawking has no problem presenting ridiculous things. he had the guts to say that black holes evaporated. he would have said something about this a long time ago if he discovered something. the space train will not calculate a lower speed. what youre saying is simply wrong

also, how would the LHC prove him wrong? how would they know how far the particles traveled in time? did they put a clock on them? no. they did the math using einsteins equations

I believe I said they would never catch the light because it's in their ref.frame and they can't go faster than light in their ref. frame.

Explain why the space train will not calculate a different speed? Same number of revolutions as viewed from the train and on earth but different experiences for time. Revolutions + different time reference translates to a different velocity. The velocity must change for one of them.

Show me how I am wrong and if I agree, I will accept that you are right.

They will know how far the particles traveled in time when they reappear and are measured in the future. The numbers in the article indicate 1/7000th. Albert's equations indicate 1/70. Now why is that?

edit: also the article made it a point to spell out oneseventhousandth so there is no indication of an error.

Edited May 5, 2010 by Astute One

[Drj312]

Here's the next question (I apologize for beating the train example to death):

Say I am a passenger in the train going at 0.9999c, and from the back of the train I turn on a hand-held laser pointed at the front of the train (this example is used in the Hawking program using a little girl), does the laser beam slow down, or the whole train slow down to accomodate? (so that c is not exceeded) In the show, they showed the little girl moving in slow motion, but if I were in the train, I wouldn't see her, or my hand-held laser slow down, right? If instead, the whole train slows down to accommodate my hand-held laser, that would be equally weird - a whole train slows down because I turned on a laser? Both possibilities sound wrong to me.

c will not be exceeded. the light will still travel at c away from you. light travels away at c in every reference frame. no matter what, light will travel at c. to stationary observers, the same laser beam will be traveling at c away from them. it doesnt make much sense at first but that is how it is

[Astute One]

Here's the next question (I apologize for beating the train example to death):

Say I am a passenger in the train going at 0.9999c, and from the back of the train I turn on a hand-held laser pointed at the front of the train (this example is used in the Hawking program using a little girl), does the laser beam slow down, or the whole train slow down to accomodate? (so that c is not exceeded) In the show, they showed the little girl moving in slow motion, but if I were in the train, I wouldn't see her, or my hand-held laser slow down, right? If instead, the whole train slows down to accommodate my hand-held laser, that would be equally weird - a whole train slows down because I turned on a laser? Both possibilities sound wrong to me.

I don't think the train slows. Only the time in the train. That's why the girl was in slow motion.

[Professor Buzzkill]

Here's the next question (I apologize for beating the train example to death):

Say I am a passenger in the train going at 0.9999c, and from the back of the train I turn on a hand-held laser pointed at the front of the train (this example is used in the Hawking program using a little girl), does the laser beam slow down, or the whole train slow down to accomodate? (so that c is not exceeded) In the show, they showed the little girl moving in slow motion, but if I were in the train, I wouldn't see her, or my hand-held laser slow down, right? If instead, the whole train slows down to accommodate my hand-held laser, that would be equally weird - a whole train slows down because I turned on a laser? Both possibilities sound wrong to me.

My understanding (and i may be wrong here) is that the measured speed of light doesn't change no matter how fast you are going. If you were traveling at 95% of the speed of light in space and saw the light from a distant star, even though the light might take more or less time to reach you depending on your direction of travel, it will still be measured at the speed of light.

So technically nothing slows down or speeds up, but when you measure it, lightspeed will always be a constant

[Astute One]

c will not be exceeded. the light will still travel at c away from you. light travels away at c in every reference frame. no matter what, light will travel at c. to stationary observers, the same laser beam will be traveling at c away from them. it doesnt make much sense at first but that is how it is

Agreed. No one can ever observe light traveling faster than the speed of light. Time and distance are the variables and c is the constant.

[Drj312]

I believe I said they would never catch the light because it's in their ref.frame and they can't go faster than light in their ref. frame.

Explain why the space train will not calculate a different speed? Same number of revolutions as viewed from the train and on earth but different experiences for time. Revolutions + different time reference translates to a different velocity. The velocity must change for one of them.

Show me how I am wrong and if I agree, I will accept that you are right.

They will know how far the particles traveled in time when they reappear and are measured in the future. The numbers in the article indicate 1/7000th. Albert's equations indicate 1/70. Now why is that?

the train will not calculate a different speed.

here we go, say the earth is 100 meters in circumference to make it easy. so the train is 1 meter. if they travel at 1 m/s, then they should go around in 100 seconds. that is for people on the train.

now for the man at the station. lets imagine 1 m/s is close to the speed of light. due to lorentz contraction, the train will appear to be shorter in length. lets just say it will be .5 meters.

100/.5=200. so for the man on the station the train appears to go around in 200 seconds instead of 100. same speed, same revolutions, different times

[Astute One]

After another two years of full thrust the ship would reach its top speed, 99 per cent of the speed of light. At this speed, a single day on board is a whole year of Earth time. Our ship would be truly flying into the future.

Interesting.

One question. At 0.9999c, time dilation is 1/71 using Albert's equation. So why does he say one day equals 1 year (365 days)? It should be 71 days. This is another clue something is not quite right. Hawking isn't going to make this silly mistake unless he meant to.

Could this be a subtle hint to the science world?