# Time and Light: A Curious Link

• Keystone
In summary, there is a link between light and time, as light has energy and can warp the surrounding region of spacetime. When light bends around something without interaction, it can cause an increase in time dilation in that region. However, this effect is not exclusive to light and anything else in the region can also cause time dilation. The idea that "the faster you get, the slower time goes for you" is not entirely accurate, as time dilation is symmetrical and relative to the observer. The concept of time stopping at the speed of light is also not true, as it is not possible for an object to be moving at the speed of light relative to itself. It is important to always consider the speed of objects relative to each other when
Keystone
Hi, so I was wondering what specifically the link is between light and time, I know that the faster you get the slower time goes for you, and if you go light speed time does not progress for you, but what is it when light bends around something without interaction? Would it cause no time to pass within the space that light bends around?

Light's path is bent by gravity, just like any other object. There is nothing special about this.

Ok

Last edited:
Drakkith said:
Light's path is bent by gravity, just like any other object. There is nothing special about this.
So does light effect time at all?

Keystone said:
So light dosent effect time at all?

Your question is not very clear. Light has energy, so it can warp the surrounding region of spacetime just like an object with mass can. This will increase the amount of time dilation in the region, but so will anything else you put there.

Keystone said:
I know that the faster you get the slower time goes for you
You'll hear non-scientists saying that, but it's not quite right. Consider that right now, even as you're reading this, you are moving at 99% of the speed of light relative to some observer in some far distant galaxy. Do you think that time is going slower for you? Or that if that distant observer were to change his speed so that you were moving at only 98% of the speed of light relative to him, time would speed up a little bit for you?
What relativity does say is that if you can arrange to measure the time between ticks of a clock that is moving relative to you (and this is harder than it sounds) you will find that that while your clock, at rest relative to you, ticks ten times the moving clock will tick somewhat less than ten times. However, this effect is completely symmetrical - someone at rest relative to the other clock will consider hiself to be at rest and find that your clock, moving relative to him, is the one that is running slow. Thus, time does not "get slower for you" as you go faster - instead, you find that clocks moving relative to you run slower than a clock at rest relative to you.

and if you go light speed time does not progress for you
Again, that's not quite right. As far as you are concerned, you are at rest and everyone else is moving relative to you... and it is not possible for some other clock to be moving at the speed of light relative to you, so the question never arises. It is true that a light signal is always moving at the speed of light relative to you (that's actually the basis of all of special relativity) but a light signal isn't a clock. There's an FAQ on this already: https://www.physicsforums.com/threads/rest-frame-of-a-photon.511170/

Drakkith said:
Your question is not very clear. Light has energy, so it can warp the surrounding region of spacetime just like an object with mass can. This will increase the amount of time dilation in the region, but so will anything else you put there.
Oh ok, thank you!

Nugatory said:
You'll hear non-scientists saying that, but it's not quite right. Consider that right now, even as you're reading this, you are moving at 99% of the speed of light relative to some observer in some far distant galaxy. Do you think that time is going slower for you? Or that if that distant observer were to change his speed so that you were moving at only 98% of the speed of light relative to him, time would speed up a little bit for you?
What relativity does say is that if you can arrange to measure the time between ticks of a clock that is moving relative to you (and this is harder than it sounds) you will find that that while your clock, at rest relative to you, ticks ten times the moving clock will tick somewhat less than ten times. However, this effect is completely symmetrical - someone at rest relative to the other clock will consider hiself to be at rest and find that your clock, moving relative to him, is the one that is running slow. Thus, time does not "get slower for you" as you go faster - instead, you find that clocks moving relative to you run slower than a clock at rest relative to you.Again, that's not quite right. As far as you are concerned, you are at rest and everyone else is moving relative to you... and it is not possible for some other clock to be moving at the speed of light relative to you, so the question never arises. It is true that a light signal is always moving at the speed of light relative to you (that's actually the basis of all of special relativity) but a light signal isn't a clock. There's an FAQ on this already: https://www.physicsforums.com/threads/rest-frame-of-a-photon.511170/
Thank you! I don't understand it all yet ( I'm not taking my high school physics class until next year ) but I will try to understand relativity better :)

Keystone said:
Thank you! I don't understand it all yet ( I'm not taking my high school physics class until next year ) but I will try to understand relativity better :)

When it comes to relativity, you will be way ahead of the game if you can just train yourself to always, always, always say what speeds are relative to.

You're at rest relative to the surface of the Earth underneath you (unless you happen to be walking, running, or in some sort of vehicle right now), but that Earth underneath you is spinning around around the planet's axis, moving around the sun at many kilometers/sec, the sun is wandering through the galaxy at even greater speeds, and the whole galaxy is racing through the universe at absurd speeds relative to other distant galaxies. So it makes no sense to talk about a speed without saying what it's relative to.

Nugatory said:
When it comes to relativity, you will be way ahead of the game if you can just train yourself to always, always, always say what speeds are relative to.

You're at rest relative to the surface of the Earth underneath you (unless you happen to be walking, running, or in some sort of vehicle right now), but that Earth underneath you is spinning around around the planet's axis, moving around the sun at many kilometers/sec, the sun is wandering through the galaxy at even greater speeds, and the whole galaxy is racing through the universe at absurd speeds relative to other distant galaxies. So it makes no sense to talk about a speed without saying what it's relative to.
Thanks ! Also, so in the way of light, so using light as a form of mass, or energy to distort the relativity in time ( and matey from this I mean in a place that has little gravity so that that isn't effecting anything ) if you where to bend the light around an excellerating object what effect would that have on the time relativity of the space being spiraled around?

Last edited by a moderator:
Keystone said:
if you where to bend the light around an accelerating object what effect would that have on the time relativity of the space being spiraled around?

As phrased, that question cannot be answered because the phrase "time relativity of space" makes no sense and I'm not sure what you do mean by it. I will suggest, though, that you'll find it easier to discuss general relativity is you first nail down your understanding of special relativity, which covers the behavior of time and light in flat space-times.

Nugatory said:
As phrased, that question cannot be answered because the phrase "time relativity of space" makes no sense and I'm not sure what you do mean by it. I will suggest, though, that you'll find it easier to discuss general relativity is you first nail down your understanding of special relativity, which covers the behavior of time and light in flat space-times.
Ok, also by time relativity of space, I meant the time for that specific part of space as compared to its surroundings, also sorry in the last thing I posted I didn't mean I'm I meant in.

## 1. What is the connection between time and light?

Time and light are closely linked because light travels at a constant speed, known as the speed of light. This speed is a fundamental constant in the universe and plays a crucial role in our understanding of time and space. As light travels, it also carries information about the time it took to reach its destination, making it a key factor in measuring and understanding time.

## 2. How does light affect our perception of time?

Our perception of time is heavily influenced by light. The speed of light is so fast that we often perceive events as happening instantaneously. This can lead to the distortion of time, making it seem shorter or longer than it actually is. Additionally, the intensity and color of light can also affect our perception of time, with brighter and warmer colors often making us feel like time is passing more quickly.

## 3. Can time be affected by light?

Yes, time can be affected by light in various ways. The Theory of Relativity, developed by Albert Einstein, states that time is relative and can be affected by factors such as the speed of light and gravity. For example, time appears to pass slower for objects moving at high speeds, and light can also bend the fabric of space-time, affecting the rate at which time passes.

## 4. How does light travel through time?

Light itself does not travel through time in the traditional sense. Instead, it travels through space-time, which is a four-dimensional continuum that combines space and time. Light always travels at the speed of light, regardless of the observer's perspective, and its journey through space-time can be thought of as a straight line.

## 5. Can we manipulate time using light?

Currently, we do not have the technology to manipulate time using light. However, there are ongoing research and experiments exploring the possibility of manipulating time using highly intense laser beams. These experiments aim to achieve time dilation, where time appears to slow down or stop for a specific object or observer. While this is still in the realm of theoretical physics, it could have significant implications for our understanding of time and the universe.

• Special and General Relativity
Replies
10
Views
2K
• Special and General Relativity
Replies
58
Views
2K
• Special and General Relativity
Replies
2
Views
932
• Special and General Relativity
Replies
35
Views
3K
• Special and General Relativity
Replies
45
Views
3K
• Special and General Relativity
Replies
167
Views
6K
• Special and General Relativity
Replies
98
Views
2K
• Special and General Relativity
Replies
65
Views
4K
• Special and General Relativity
Replies
12
Views
2K
• Special and General Relativity
Replies
27
Views
2K