Alien abduction or time travelers?

lamme, you said:

"Einstrein, or no Einstein...it seems hard to fathom that if you were blindfolded on earth (so the speed of light factor doesn't influence what you are seeing), and then put in a space ship and sent deep into space exceeding the speed of light, and returned at this speed (still blindfolded), and you got out of the space ship and went home (still blindfolded) and you took off your blindfold....my guess is that you neither went forward or backwards in time to any big degree.

My reasoning is thus: Light travels at 186,000 mps. You traveled 372,000 miles round trip at twice the speed of light. I say that time went forward by 1 second. (If you went at the speed of light, it would have been 2 seconds. Now suppose your traveled distance was 1000 times greater. You would arrive home in 500 seconds (about 8 minutes), instead of the 16 minutes that you would have if you went at the speed of light."

Most of us alive today will never be able to travel at speeds approaching the speed of light. We have to be content with maybe at best, travelling at mach 2 in Concord. Astronauts may get up to faster speeds but nowhere near the 186,000 miles per second. Therefore physics as defined by Newton, have been quite adequate. However, when we get up to the speed of light, Newton's laws are no longer good enough. Relativity is all about relative speed to an observer. A stationary observer can view two trains heading towards each other at a combined speed of 100 mph. In fact they are each travelling clocking at fifty miles an hour on their own individual speedos inside the cabins.

In another scenario where two trains on separate tracks are travelling in the same direction in parallel. Both trains relative to each other are stationary, but to the observer watching from the side, both are moving away from him at fifty mph.

Now at speeds close to light speed, something wierd happens. For example, if a rocket was travelling at the speed of light and it fired a missile ahead of itself at the speed of light, relative to a stationary observer, the missile speed would still be at the speed of light and not double the speed of light as expected.

Einstein has calculated this and can express the effect mathematically. He also says that at speeds of light for a traveller relative to a stationary observer, time would slow down, although the traveller would not be aware of this. It is theoretically possible for a space traveller to set off on a light speed journey and have his young sons wave him goodbye, only to return two or three years later to meet his sons who are now older than him.

This time dilation effect has been proven scientifically by setting two very accurate quartz clocks to identical times and sending one off in a jet for several hours. On the return, the clock that flew was a few nano seconds slower than the clock that stayed behind. The degree of time slowing calculates out exactly to Einstein's formula.

The same effect would be created if you approached the event horizon of a black hole. Time would dilate in exactly the same and predictable way relative to an oberver not affected by extreme gravitational force. So time, gravity and space are all interelated in this way. In fact Einstein said that gravity is simply a deformation of space caused by mass. If you can imagine an elastic membrane steched out flat and you place a ball bearing on top of it, it would distort around the area of mass. A body approaching the deflected area would tend to move towards the ball bearing caught by the curvature surrounding it. Eventually after rotating around it a couple of times or more (i.e. orbiting) it fall in and touch it as if gravity had been the cause. Space distorts in the same way. If the ball bearing has exceptional mass the membrane would distort to such a degree that a deep hole would form, and this is the analogy to a black hole.

You must read the book as recommended above, for a much better and more facinating narrative.
 
Thanks again, Explorer. But in the trains scenario, it sounds like we are taking observations rather than reality, again. Actual time travel, forward or backward would have to be based in reality, not just what is relative to something else, I would think.

Regarding time dilation with the quartz watches? I read the same test, once. I scoffed and mumbled to myself that the scientists are jumping too hastily to conclusions. That maybe there are other forces at work that slowed the traveling watch, such as acceleration, gravity, or...who knows. How does a quartz watch 'know' anything about spped of light/relativity to the space/time continuum. Because, the watch, like my rants about an observer having his eyes closed the whole time...has no eyes. :wink:

This whole business with time and space relativity seems to me that some scientists had/have too much time on their hands, and have drummed up non-useable theoretical poppie-cock. They could join those who are testing to see if a tree falls in the woods, and you're not there...if it really makes a noise.

But in reality, I'm not as cocky as I sound here. I probably will take you up on trying to get ahold of one of the easy to follow books on the subject.

Thanks for going through the effort you have in trying to explain this to some of us here.
 
Iamme said:
Thanks again, Explorer. But in the trains scenario, it sounds like we are taking observations rather than reality, again. Actual time travel, forward or backward would have to be based in reality, not just what is relative to something else, I would think.
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But both trains are on the earth, which is moving. And the solar system is moving around the center of the milky way galaxy.

Let's say you jump from one of those trains to another. From your perspective the other train is stationary. Thus you can make the jump across. This is real. Not an illusion. From a stationary obeserver's point of view, you not only jumped the distance from one train to another, but also covered the distance that the train covered while you were jumping. This also is real.

What is the benchmark of all these relative motions? That's the question that Einstein asked himself. His exploration led him to the answer. It's the speed of light in a vaccum.

Here's another example. (Cribbed unshamedly from Cosmos) A bicycle rider is coming down the street, which is parallel to you. He approaches a 4 way interection. A horse and buggy are coming straight towards you, also approaching the intersection. If the speed of light were not absolute, it follows that the image of the horse and buggy (the light reflecting off of it and entering your eyes) would add it's speed to the photons of light. Thus, the image of the horse and cart would arrive at your eyes at the speed of light plus the speed of the horse and cart. Our friend on the bicycle has a near miss as both he and the horse cart almost collide. From your perspective, the horse and cart image should reach you before the collision. You see the horse buggy swerve for no apparent reason. The bicycle then arrives and swerves as well. From your perspective, he's reacting to a horse and buggy that is no longer in his way.

Nothing like this in nature or laboratory experiments has ever happened.

Instead, to all obeservations, the speed of light is absolute. You may never add your speed to the speed of light.

Regarding time dilation with the quartz watches? I read the same test, once. I scoffed and mumbled to myself that the scientists are jumping too hastily to conclusions. That maybe there are other forces at work that slowed the traveling watch, such as acceleration, gravity, or...who knows. How does a quartz watch 'know' anything about spped of light/relativity to the space/time continuum. Because, the watch, like my rants about an observer having his eyes closed the whole time...has no eyes. :wink:
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Indeed. The watch doesn't know any better. But it is made to tick at the rate of one second per second. It's just a mechanical process.

Then we accelerate the clock. And it ticks more slowly than a clock left behind. This experiment has also been done with atomic particles that decay more slowly as the approach the speed of light. (In particle accelerators, for example.)

Time is a relative variable, affected by acceleration. This is a concequence of time and space being the same thing.

This whole business with time and space relativity seems to me that some scientists had/have too much time on their hands, and have drummed up non-useable theoretical poppie-cock. They could join those who are testing to see if a tree falls in the woods, and you're not there...if it really makes a noise.
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But it's not theory. It's confirmed by experiment and observation. It's impact on modern science was profound and lasting.
 
Ratman_tf said:


Here's another example. (Cribbed unshamedly from Cosmos) A bicycle rider is coming down the street, which is parallel to you. He approaches a 4 way interection. [/B]
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So if a torch was travelling at the speed of light, would it build up a light version of a 'sonic boom’?
 
Purple---Hi. Ratman_tf already explained above that it would not. The speed of light cannot be added onto by shooting light off of moving light. (I.e., having a flashlight travel at the speed of light, forward, with it's light on.) The speed of light is the final (known/never disproven) speed. You can't use various tricks to increase the speed of light.

With sound waves, you can create the Doppler effect. Similarly, with light, you can create this Doppler effect. When a star is traveling AWAY from us at some great speed, we can see the affects of this by what is called a 'red shift'.

I did an experiment with light that fasxcinated me. I held my penlight to a wall, from about 4 feet away, and observed it's brightness, and it's scatter pattern. Then, I put the penlight inside a paper toweling tube to create a rifle barrel affect. This concentrated the beam. What do you think it did to the brightness? THEN, I began to narrow the tube, at the exit end. You already know what happens when you do this with water through a hose with a spray nozzle at the end. So, what do you think this did to the light's intensity?
 
Iamme said:
I did an experiment with light that fasxcinated me. I held my penlight to a wall, from about 4 feet away, and observed it's brightness, and it's scatter pattern. Then, I put the penlight inside a paper toweling tube to create a rifle barrel affect. This concentrated the beam. What do you think it did to the brightness? THEN, I began to narrow the tube, at the exit end. You already know what happens when you do this with water through a hose with a spray nozzle at the end. So, what do you think this did to the light's intensity? [/B]
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Excellent experiment. :)
 
Purple Tentacle said:


So if a torch was travelling at the speed of light, would it build up a light version of a 'sonic boom’?
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Matter cannot be accelerated to the speed of light. That question cannot be answered.

The sonic barrier was a design problem. The speed of light is a fundamental law of physics.

If you could accelerate a torch to near the speed of light, say 99.999999999999999%, the photons leaving the torch would still be traveling at the speed of light. You may slow light down (as in refracting an image) but you can never speed it up past light speed.
 
so if the torch was traveling at the speed of light, and it is generating light, which cannot go faster than the speed of light, would the light from the torch appear stationary from the torch's perspective?
 
Purple Tentacle said:
so if the torch was traveling at the speed of light, and it is generating light, which cannot go faster than the speed of light, would the light from the torch appear stationary from the torch's perspective?
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Yes. In the context of this thought experiment. But remember that the torch still can't be accelerated to the speed of light, since it's made of matter.
 
Ratman said

"Yes. In the context of this thought experiment. But remember that the torch still can't be accelerated to the speed of light, since it's made of matter"

The person holding the torch would not notice any difference. The torch to him would behave perfectly normally at the speed of light. Remember that it is "relative" speeds that we are talking here. Only a stationary observer would notice an unusual effect with the torch.
 
Explorer said:
Ratman said

"Yes. In the context of this thought experiment. But remember that the torch still can't be accelerated to the speed of light, since it's made of matter"

The person holding the torch would not notice any difference. The torch to him would behave perfectly normally at the speed of light. Remember that it is "relative" speeds that we are talking here. Only a stationary observer would notice an unusual effect with the torch.
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Hm. This is starting to confuse me now. How can the light being generated from the torch appear normal to the person holding it (who is travelling at light speed) while still not travelling faster than light? Are you saying the speed of light is relative? And would't that be against general relativity?
 
Ratman_tf said:


Hm. This is starting to confuse me now. How can the light being generated from the torch appear normal to the person holding it (who is travelling at light speed) while still not travelling faster than light? Are you saying the speed of light is relative? And would't that be against general relativity?
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The speed of light is the same for everyone no matter how fast you're travelling relative to someone else. This is the essence of its "weirdness". Moreover no objevt can travel faster than the speed of light relative to anything else.

Imagine 3 objects "A", "B" and "C". "B" is "stationary, "A" is travelling from it at 99% of the speed of light, and "C" is alos travelling from it at 99% of the speed of light, but in the precise opposite direction. The speed of "A" relative to the speed of "C" will still be less than the speed of light.
 
Ian---Yet this doesn't seem to hold any logic as to why this should be.

Suppose B is a point on the railroad tracks. Suppose A train is moving away from point B at speed X. Now suppose train C is moving away from point B, in the opposite direction, also at speed X. If you waited a minute, and then calculated the distance between A and C...it would be 2X. In actual numbers, if the trains were moving away from each other at 50 mph...from either ones perspective, the opposite train would be going 100 mph. But from perspective B, each would be at 50 mph...naturally, obviously. Why the heck should light be different (with the illustration YOU gave)?!

However...if the LIGHT from A...and the LIGHT from C were facing each other , as the light SOURCES moved away from each other...this poses a different problem. From each's perspective, the light would slow into a red shift. Also, from the perspective of point B. Would the red shift be more so, for A, in relation to C?..than B, in relation to A or B? I would THINK so...but I'm not sure.

Light is weird. Remember when I told of my experiment with light in a paper tube? When you put it in the tube, thinking you will cut down the scatter pattern and concentrate it on the wall to be a brighter beam? It don't happen. Also, when you restrict the opening...the light restricts also. It doesn't intensify...it doesn't pile on..it doesn't behave like water being shot through a sprayer nozzle. It doesn't compress together, like air. But neither does water compress, but the intensity...the force of water indeed increases, through a restriction. For a better experiment though, I should be using tubing with reflective coating inside, rather than light absorbing paper tubing...to be sure of this.
 
Iamme said:
Ian---Yet this doesn't seem to hold any logic as to why this should be.

Suppose B is a point on the railroad tracks. Suppose A train is moving away from point B at speed X. Now suppose train C is moving away from point B, in the opposite direction, also at speed X. If you waited a minute, and then calculated the distance between A and C...it would be 2X.
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I don't know a great deal about relativity but I believe from the perspective of B it would. From the perspective of either A or C it would be very slightly less than 2X at the speed that trains typically go.

In actual numbers, if the trains were moving away from each other at 50 mph...from either ones perspective, the opposite train would be going 100 mph. But from perspective B, each would be at 50 mph...naturally, obviously. Why the heck should light be different (with the illustration YOU gave)?!
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You don't use a simple addition rule in calculating the velocity of one thing relative to another. Trains A and B would not be moving apart from each other at 100mph, but rather at a speed very slightly less than 100mph. Something like 99.9999mph or whatever. Of course both C and A would be moving from B at 50mph.

BTW if trains A and C were moving from B at 99% of the speed of light, the relative speeds of A and C respective to each other would still be less than the speed of light.

Elementary relativity stuff.
 
Fitting to revive a four-year-old thread to talk about time travel.

You have to start with a premise or two in order to address this issue-- for the sake of argument.

1. If the UFOs are flying craft and are not operated by our government; and

2. If many elements of the story are anthropomorphic, including "humanoid" pilots; and

3. If it is all but impossible to time-travel and only a bit more difficult to travel great distances through space; then

Either the UFOs are from another era or are the product of a nearby, related species.

It is also far more likely that the UFOs are human inventions than vehicles from a far planet. We have motive to visit ourselves in the past, if at all possible; if it is possible to invent time-travel, we will, and we will inevitably use it. While the same is true of space travel, the distances are a puzzle.

Alien beings are not the easiest answer. Drake's Equation won't get you very far, either.
 
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