Jump to content

Approaching the speed of light


EquisDeXD

Recommended Posts

From the photon's point of view, yes.

 

It takes zero time IN THE PHOTON'S FRAME OF REFERENCE

 

I'm beginning to understand all of this now. However, one thing I still don't get. If you were traveling at 90% the speed of light, this means that from your frame of reference, everything else is slowing down.

If everything else is slowing down, why is it that you would be able to see into the future?

Link to comment
Share on other sites

I'm beginning to understand all of this now. However, one thing I still don't get. If you were traveling at 90% the speed of light, this means that from your frame of reference, everything else is slowing down.

If everything else is slowing down, why is it that you would be able to see into the future?

 

I wouldn't trust him, I'd wait until swan can clear it up.

Link to comment
Share on other sites

I'm beginning to understand all of this now. However, one thing I still don't get. If you were traveling at 90% the speed of light, this means that from your frame of reference, everything else is slowing down.

If everything else is slowing down, why is it that you would be able to see into the future?

Well, not everything. Just those things that you are moving very fast relative to. If something else is at rest relative to you then their clock does not seem to be running slowly. To another object you may be moving at .05c.

 

What do you mean by 'see into the future'?

Link to comment
Share on other sites

 

What do you mean by 'see into the future'?

 

Well, while I was researching this elsewhere to try and gain a grasp on the idea, I came across this.

"The fastest hypothetical forms of propulsion that I have heard of recently can propel a spacecraft to ~ 10% of the speed of light. From one light year away, you can see the Earth as it was one year ago. But traveling at 10% of the speed of light we will get there in ten years. So (ignoring time dilation) if you travel one light year away from the Earth, you will actually see the Earth as it will be nine years forward from your departure date, instead of one year back."

Although, considering that is ignoring time dilation, I suppose it's wrong?

Link to comment
Share on other sites

Well, while I was researching this elsewhere to try and gain a grasp on the idea, I came across this.

"The fastest hypothetical forms of propulsion that I have heard of recently can propel a spacecraft to ~ 10% of the speed of light. From one light year away, you can see the Earth as it was one year ago. But traveling at 10% of the speed of light we will get there in ten years. So (ignoring time dilation) if you travel one light year away from the Earth, you will actually see the Earth as it will be nine years forward from your departure date, instead of one year back."

Although, considering that is ignoring time dilation, I suppose it's wrong?

That is tough to parse. I think what they mean is: You see earth nine years forward of your depararture date, but by the time you get one light away, your departure date was 10 years ago. So you are still not seeing into the future. I think the point was that since you are travelling 0.1c for 10 years, over the course of the trip you have stayed ahead of one year's worth of light coming from the earth, so even though you travelled for 10 years, you see the earth as it was 9 years ago instead of 10.

Link to comment
Share on other sites

That is tough to parse. I think what they mean is: You see earth nine years forward of your depararture date, but by the time you get one light away, your departure date was 10 years ago. So you are still not seeing into the future. I think the point was that since you are travelling 0.1c for 10 years, over the course of the trip you have stayed ahead of one year's worth of light coming from the earth, so even though you travelled for 10 years, you see the earth as it was 9 years ago instead of 10.

 

Ah, yes, that does make sense. OK, I've got a bit of a grasp on this now, thank you.

Link to comment
Share on other sites

That is tough to parse. I think what they mean is: You see earth nine years forward of your depararture date, but by the time you get one light away, your departure date was 10 years ago. So you are still not seeing into the future. I think the point was that since you are travelling 0.1c for 10 years, over the course of the trip you have stayed ahead of one year's worth of light coming from the earth, so even though you travelled for 10 years, you see the earth as it was 9 years ago instead of 10.

 

No, what it means is from your own point of view, your time flows normally, but to the outside world, your time is slowed down, so while nine years passes on earth, you only count one year of time passing. As you approach the speed of light, the rate it which time passes for you relative to other subluminal frames of reference slows down, so it's only natural you'd age at a slower rate, that's also why if you go near a black hole, then come back to earth, you'd find people who use to be younger than you are now in fact older than you because in the presence of higher gravity, time flows more slowly.

Edited by EquisDeXD
Link to comment
Share on other sites

No, what it means is from your own point of view, your time flows normally, but to the outside world, your time is slowed down, so while nine years passes on earth, you only count one year of time passing.

Not even close. If you are going to keep saying 'no' to posts I make please first check to make sure you are correct.

Link to comment
Share on other sites

I'm beginning to understand all of this now. However, one thing I still don't get. If you were traveling at 90% the speed of light, this means that from your frame of reference, everything else is slowing down.

If everything else is slowing down, why is it that you would be able to see into the future?

I don't recall anyone saying anything about seeing into the future.

 

If you travel at 0.995c, the factor by which time is dilated or length contracted is 10. If you were in a rocket ship going to a place that was 10 light years away as measured by someone at rest (on your home planet), when you were at speed, you would see that distance as only 1 LY and since you are going very close to c, it will take you a smidge over a year to make that trip. Meanwhile, observers on your home planet see that trip as taking just over 10 years, as it must — light makes the trip in 10, and the ship is going just a little slower. They will also observe that the ship's clock was running slow by a factor of 10. So there is a consistent picture (in each frame) of the trip taking as long as it should. When the rocket ship returns, another 10+ years passes on the home planet, while the ship's clock advances just over a year, again. Everyone on the home planet has aged over 20 years, while the rocket's inhabitants have aged just over 2 (We're ignoring any time spent at the destination or accelerating as these effects can be made arbitrarily small)

Link to comment
Share on other sites

"you will actually see the Earth as it will be nine years forward from your departure date, instead of one year back." As I already stated, this quote was what made me think you could see into the future. The way it is worded makes it seem that way.

As I also already stated, the problem has been cleared up for me and I now understand.

Thank you for elaborating anyway, albeit in quite a snide way.

 

I don't recall anyone saying anything about seeing into the future.

 

If you travel at 0.995c, the factor by which time is dilated or length contracted is 10. If you were in a rocket ship going to a place that was 10 light years away as measured by someone at rest (on your home planet), when you were at speed, you would see that distance as only 1 LY and since you are going very close to c, it will take you a smidge over a year to make that trip.

 

Also, you've made it a bit more confusing for me here. If it takes light 10 years, then traveling at light speed would take you 10 years, not 1.

Link to comment
Share on other sites

Also, you've made it a bit more confusing for me here. If it takes light 10 years, then traveling at light speed would take you 10 years, not 1.

That's the part about relativity that often causes a lot of confusion. The planet-based observers see that it takes 10 years, but the rocket occupants don't. For them time has run slow, even though they will never notice on their own. They simply think it only took a year (1.005 years, to be precise), and that the trip was only 1 LY in distance, and all of their instrumentation agrees.

Link to comment
Share on other sites

That's the part about relativity that often causes a lot of confusion. The planet-based observers see that it takes 10 years, but the rocket occupants don't. For them time has run slow, even though they will never notice on their own. They simply think it only took a year (1.005 years, to be precise), and that the trip was only 1 LY in distance, and all of their instrumentation agrees.

 

Ah, I understand. This matches what was said earlier about photons measuring no time at all for any journey.

Although, if I may stray off topic a little. What exactly is theorized to happen to light in regard to a black hole; if light has no mass, why does it succumb to the gravity of a black hole, and what happens to time in there?

Edited by ElasticCollision
Link to comment
Share on other sites

Ah, I understand. This matches what was said earlier about photons measuring no time at all for any journey.

Although, if I may stray off topic a little. What exactly is theorized to happen to light in regard to a black hole; if light has no mass, why does it succumb to the gravity of a black hole, and what happens to time in there?

 

Per Einstein's general relativity, gravity is the warping of time and space. This "spacetime curvature" affects the path of all particles, including massless photons (light particles). For example, light from a star passing very close to the Sun is bent or curved by the Sun's spacetime curvature. The verification of this effect in a 1919 solar eclipse made Einstein world famous.

 

Consider light inside the event horizon of a black hole. Here spacetime curvature (gravity) is so great that space is stretched to the point where the frequency of that light is stretched to zero. So no light inside the event horizon is emitted to the outside world.

 

Light is an electromagnetic wave, with regular peaks and valleys. You can think of each peak and valley as the tick and tock of a clock. So when light's frequency is stretched to zero, it is equivalent to "freezing" time. Thus to an observer far away, time at the event horizon of a black hole appears to stand still.

 

See link for more details: http://imagine.gsfc....rs/970618a.html

 

My website: http://www.marksmodernphysics.com/

Edited by IM Egdall
Link to comment
Share on other sites

Per Einstein's general relativity, gravity is the warping of time and space. This "spacetime curvature" affects the path of all particles, including massless photons (light particles). For example, light from a star passing very close to the Sun is bent or curved by the Sun's spacetime curvature. The verification of this effect in a 1919 solar eclipse made Einstein world famous.

 

Consider light inside the event horizon of a black hole. Here spacetime curvature (gravity) is so great that space is stretched to the point where the frequency of that light is stretched to zero. So no light inside the event horizon is emitted to the outside world.

 

Light is an electromagnetic wave, with regular peaks and valleys. You can think of each peak and valley as the tick and tock of a clock. So when light's frequency is stretched to zero, it is equivalent to "freezing" time. Thus to an observer far away, time at the event horizon of a black hole appears to stand still.

 

See link for more details: http://imagine.gsfc....rs/970618a.html

 

My website: http://www.marksmodernphysics.com/

 

Wow, fascinating. Thank you for the level of detail.

Edited by ElasticCollision
Link to comment
Share on other sites

Per Einstein's general relativity, gravity is the warping of time and space. This "spacetime curvature" affects the path of all particles, including massless photons (light particles). For example, light from a star passing very close to the Sun is bent or curved by the Sun's spacetime curvature. The verification of this effect in a 1919 solar eclipse made Einstein world famous.

 

Consider light inside the event horizon of a black hole. Here spacetime curvature (gravity) is so great that space is stretched to the point where the frequency of that light is stretched to zero. So no light inside the event horizon is emitted to the outside world.

 

Light is an electromagnetic wave, with regular peaks and valleys. You can think of each peak and valley as the tick and tock of a clock. So when light's frequency is stretched to zero, it is equivalent to "freezing" time. Thus to an observer far away, time at the event horizon of a black hole appears to stand still.

 

See link for more details: http://imagine.gsfc....rs/970618a.html

 

My website: http://www.marksmodernphysics.com/

 

The frequency of light stretches to 0? I thought it stretched to infinity as it approached the event horizon, but in any case, to any outside frame of reference, for whatever's in the black hole time would be stopped, while someone inside would count normally?

There's something about seeing frozen people at the event horizon that doesn't make sense. If they already passed the event horizon, what is light reflecting off of? Theoretically if it works that way, black holes should be completely visible because you'd see the stopped time of all the dust, meteors and gas they've absorbed, which over a long time I'm sure accumulates to a lot.

Edited by EquisDeXD
Link to comment
Share on other sites

The frequency of light stretches to 0? I thought it stretched to infinity as it approached the event horizon, but in any case, to any outside frame of reference, for whatever's in the black hole time would be stopped, while someone inside would count normally?

The frequency decreases to zero, the wavelength increases to infinity

 

There's something about seeing frozen people at the event horizon that doesn't make sense. If they already passed the event horizon, what is light reflecting off of? Theoretically if it works that way, black holes should be completely visible because you'd see the stopped time of all the dust, meteors and gas they've absorbed, which over a long time I'm sure accumulates to a lot.

 

You can't actually see the objects at the event horizon for the reason above, any light leaving the vicinity of the Black hole's event horizon is red-shifted to the point that it is undetectable.

Link to comment
Share on other sites

You can't actually see the objects at the event horizon for the reason above, any light leaving the vicinity of the Black hole's event horizon is red-shifted to the point that it is undetectable.

 

So they're saying its factual when they know there's no way they can ever observe it? That seems like counter-science to me, in fact that seems like a religion. I mean I've seen that concept in many physics books, so many that I thought they must have some evidence to support it...

Edited by EquisDeXD
Link to comment
Share on other sites

So they're saying its factual when they know there's no way they can ever observe it? That seems like counter-science to me, in fact that seems like a religion. I mean I've seen that concept in many physics books, so many that I thought they must have some evidence to support it...

 

What goes on at the event horizon of a black hole is based on solid science. It is a prediction of the theory of general relativity, our best current theory of gravity. A vast number of observations, tests, and measurements have confirmed nearly all other predictions of Einstein's theory, including a number of phenomena just outside black holes.

 

If and when an even better theory of gravity comes along (if ever), we may get a deeper understanding of the interior of black holes.

Link to comment
Share on other sites

The information that the the photon provides experiences no passage of time.

A photon that takes 8 mins to travel from the sun to our eyes can only provide information about the point in space and time from which it originated,and anything that effects it on the way.

Edited by derek w
Link to comment
Share on other sites

What goes on at the event horizon of a black hole is based on solid science. It is a prediction of the theory of general relativity, our best current theory of gravity. A vast number of observations, tests, and measurements have confirmed nearly all other predictions of Einstein's theory, including a number of phenomena just outside black holes.

 

If and when an even better theory of gravity comes along (if ever), we may get a deeper understanding of the interior of black holes.

 

Um, we don't have anything to test where time stops after a certain region in space, unless there's some top secret government program you weren't suppose to just tell everyone. Based on our information, the object should at least get smeared throughout the surface of the black hole, not just stop, and how could the atoms be measured but be in both inside and outside the black hole?

Link to comment
Share on other sites

Um, we don't have anything to test where time stops after a certain region in space, unless there's some top secret government program you weren't suppose to just tell everyone. Based on our information, the object should at least get smeared throughout the surface of the black hole, not just stop, and how could the atoms be measured but be in both inside and outside the black hole?

 

Sorry, I am not understanding you.

 

What do you mean by time stops "after a certain region in space"? We know time slows down in a gravitational field. (This has been observed many times in all kinds of tests.) The idea for an event horizon is that gravity (spacetime curvature) is so great that time slows down to the point where it stops altogether, as seen from far away. You are correct that, I as far as I know, this stopping of time has not been observed (yet). But it is a prediction contained within the construct of general relativity, which has been tested extensively in nearly all its other predictions.

 

And what do you mean "an object should at least get smeared throughout the surface of the black hole"?

 

Plus I never said the atoms are measured both inside and outside the event horizon of a black hole. Please clarify.

Edited by IM Egdall
Link to comment
Share on other sites

Sorry, I am not understanding you.

 

What do you mean by time stops "after a certain region in space"?

I mean relative to an outside observer, time stops flowing inside a black observer, which shouldn't happen infinitessimally before someone reaches the event horizon, with my current understanding, you'd only have a chance of actually seeing an object stopped if it were possible after it's crossed the event horizon when it was inside the black hole.

 

We know time slows down in a gravitational field.

Of course, that's partly why this issue was brought up.

 

 

as seen from far away.

Except it hasn't been seen from far away and it seems scientists know that it can't be seen but still assume that it happens around something of such complex physics that our own physics can't correctly describe it.

 

 

 

And what do you mean "an object should at least get smeared throughout the surface of the black hole"?

Matter naturally tries to occupy the lowest potential state, and being any possible height above the surface that's not the lowest state, is not the lowest potential state relative to the black hole.

 

Plus I never said the atoms are measured both inside and outside the event horizon of a black hole. Please clarify.

Well that's the problem I have with the whole concept. Even if time does stop, from the frame of reference of the atoms they've already passed through the event horizon, and theoretically if there was an astronaut inside the blackhole, they could observe the atoms, but how could other people observe the same atoms from the black hole? I know there's superposition, but there's no matter particle that we know of that has an uncertainty that stretches hundreds of feet really.

 

I suppose, I would understand this length contraction better if there was a visual representation of how the fabric of space changes the faster you travel.

Edited by EquisDeXD
Link to comment
Share on other sites

  • 2 months later...

I have noticed that there are some individuals who are having a difficult time understanding time dilation. Here is my attempt to try and clarify this. Imagine you are sitting on a race horse, backwards (facing the horse's tail), in the starting gate and you are looking at a clock. Now, imagine that race horse suddenly turns into a beam of light (Einstein imagining what it would be like to ride a beam of light). The time reads 11:59:57, 3 seconds away from 12:00:00 noon. The instant the clock ticks 12:00:00 noon, and not a nanosecond later, the gate opens and that beam of light takes off. Now remember, you were looking at that clock at the instant it turned 12:00:00 noon. All you will see is that clock at 12:00:00 noon. Now, one second later the clock reads 12:00:01. Will you see that clock reading 12:00:01? No. Why? Because the image of that clock now reading 12:00:01 will "never" catch up to you. You are riding a beam of light traveling at the speed of light. Nothing will be able to catch up to you, not even the image of the clock when it is reading 12:00:01 because that image is basically chasing after you at the speed of light, the "exact" same speed you are going while riding that beam of light. In order for the image of the clock at 12:00:01 to catch up to you it would have to travel "faster" then the speed of light (the speed you are traveling while riding that beam of light) and we know nothing can go faster then the speed of light. So if the image of 12:00:01 can "never" catch up to you riding that beam of light how can time pass you by? It can't. Hence, for you, time has stood still. It can "never" pass you by while you are riding that beam of light (traveling at the speed of light). In order for the image of the clock at 12:00:01 to catch up to you so you can see it you would have to be traveling slower then the speed of light. This brings me to the next step that people seem to have a problem with. Aging. If the beam of light you are riding slowed down to 99.99% of the speed of light eventually the image of the clock reading 12:00:01 will catch up to you because it is traveling "at" the speed of light. Faster then you are traveling. But, it will take quite awhile for that image to catch up to you. As the image is trying to catch up to you time is passing by a person who is "not" traveling at the speed of light in the way we would expect time to pass us by. Nothing unusual there. So, the seconds are ticking by (time passing by) for the person who is "not" traveling at the speed of light in the way we are all familiar with. However, this is "not" true for you when riding that beam of light at 99.99% of the speed of light. The image of the clock at 12:00:01 will eventually catch up to you riding the beam of light at 99.99% because the 12:00:01 image is traveling faster then you riding the beam of light. The question is "when" will the 12:00:01 image (time) catch up to you riding the beam of light? It will naturally take awhile for the 12:00:01 image (time) to catch up to you riding the beam of light. Now, let's go back to the person who is "not" traveling at the speed of light, where time is normal as we are familiar with. As the seconds tick by for him (time passing him by) the 12:00:01 image (time) has "not caught up to you riding the beam of light. Days go by, weeks go by, years go by for the person "not" traveling at the speed of light and "still" the 12:00:01 image (time) has not caught up to you riding the beam of light because there is a very, very slight difference in the speed between you riding the beam of light and the 12:00:01 image (time). Finally, the person "not" traveling at the speed of light is told that the 12:00:01 image (time) has finally caught up to you riding the beam of light, 60 years "after" the gate opened. It took 60 years for the person "not" traveling at the speed of light to be informed that the 12:00:01 image (time) has finally caught up you riding the beam of light. The person "not" traveling at the speed of light is 60 years older. Remember, you started riding the beam of light at exactly 12:00:00 and, "relative" to the person "not traveling near the speed of light, it took the 12:00:01 image (time) 60 years to catch up to you riding the beam of light because the difference in speed between you riding the beam of light and the 12:00:01 image (time) was extremely small. Since one second is "time" that means that when the 12:00:01 image (time) caught up to you (passes you by) you are only one second older, "not" 60 years older. Hope this clears up any questions anyone has about these topics.

Edited by Gatsby
Link to comment
Share on other sites

Sorry, but that's pretty much completely incorrect.

 

Time dilation is not an illusion caused by differing velocities. It's not a question of how long does it take an image to catch up with the traveler. Observers in motion relative to each other will measure the other's time as different than their own. They will always measure their own time as normal, just as they will always measure the speed of light to be the same in their own frame.

Edited by ACG52
Link to comment
Share on other sites

I didn't say time dilation was an illusion. If you are in a spaceship traveling at 99.99% of the speed of light will you age slower or faster then a person on the ground? You have your clock on the spaceshipe and he has his on the ground. According to you your clock will be normal. According to him your clock will be slower then his. If your clock is indeed slower then his will time be equal to both of you?

Edited by Gatsby
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.