# Photon Experiencing Infinity Over Time: A Relativity Question

• The Un-Observer
In summary: When we speak of an object's frame of reference, we're referring to a reference frame in which that object is at rest. Does something have to be aware to have a frame of reference? Wouldn't it have a frame of reference by the mere fact it exists?
The Un-Observer
According to relativity, from a photon's frame of reference time is instantaneous, correct? So in an instant a photon would, to its frame of reference, experience being absorbed immediately after its creation, as well as hundreds of years of travel through space in the same instant.

Say hypothetically one specific photon would never be absorbed. Perhaps most mass in the universe is converted to energy and there is nothing that would absorb it. If it kept on going forever (whether or not it would in reality) wouldn't it experience infinite amount of time instantaneously? How would that even be possible, since an instance has an end but infinity doesn't?

I apologize if this question's premises are too out of line to answer.

The Un-Observer said:
According to relativity, from a photon's frame of reference time is instantaneous, correct?

According to relativity theory, there is no "photon frame of reference". Therefore, asking what time (or anything else) looks like from the "point of view" of a photon is a meaningless question, in the context of relativity theory.

To elaborate on this a bit, an "object's frame of reference" means a reference frame in which the object itself is at rest. A photon always travels at speed c, in any inertial reference frame. Therefore, there is no inertial reference frame in which that photon is at rest.

Assigning a frame to a photon is like dividing by zero. You're just going to have a bad time if you try.

Does something have to be aware to have a frame of reference? Wouldn't it have a frame of reference by the mere fact it exists?

The Un-Observer said:
Does something have to be aware to have a frame of reference? Wouldn't it have a frame of reference by the mere fact it exists?

From wiki: In physics, a frame of reference (or reference frame) consists of an abstract coordinate system and the set of physical reference points that uniquely fix (locate and orient) the coordinate system and standardize measurements.

A reference frame is something we 'assign' to an object in order to talk about its position relative to other objects (among other things). Typically, or at least here on the forums, the object whose reference frame we are 'observing from' occupies the origin of a coordinate system. In other words, we place the object in the center of a 3-D graph (our coordinate system) so that its position is (0,0,0) and treat it as stationary with respect to our coordinate system. We then state the distance to other objects relative to this point. This allows us to simplify calculations and concepts and bring up things which aren't so obvious if our object is moving relative to our coordinate system.

We can them 'transform' our coordinate system from our original object to another, placing this new object at (0,0,0) and making it stationary with respect to this coordinate system. When we do this, all of our measurements have to change too. For example, if Object B is located at (10,0,0) and traveling at 10 m/s with respect to Object A's coordinate system, when we transform our frame to that of B, it is now object A that is moving at 10 m/s and B is now stationary at (0,0,0).

Now, the reason I bring up all that, is because one of the postulates of special relativity says that light travels at c regardless of the motion of the observer or the light source (commonly stated as light travels at c as measured by any inertial, or non-accelerating, reference frame). What this means is that no matter how our system of objects are positioned or how fast they are traveling with respect to their different frames of reference, they will always measure light as traveling at c according to their coordinate system. So if object A shoots out a beam of light, it will measure the speed of the light as c. If I then transform my reference frame to that of object B's, which is moving away from A with a velocity of 0.5c (50% the speed of light), you might expect B to measure the light as traveling at 0.5c. But it doesn't! It measures the light as moving at 1c!

This fact, that light travels at c as measured by ALL inertial reference frames, means that you cannot assign a reference frame to light at all! Remember that if we assign a reference frame to something what we are really saying is that we are centering a coordinate system on the object and treating it as stationary. But light cannot be stationary, so we cannot assign it a reference frame!

The Un-Observer said:
Does something have to be aware to have a frame of reference? Wouldn't it have a frame of reference by the mere fact it exists?

When we speak of something's reference frame, that's a convenient shorthand for a reference frame in which that something is at rest. Light moves at speed c in all reference frames, so there are no reference frames in which light is at rest.

The Un-Observer said:
Does something have to be aware to have a frame of reference?
Awareness is completely irrelevant in this context. A rock can have a valid frame of reference. Please read the FAQ that has already been referenced multiple times.

## 1. What is "Photon Experiencing Infinity Over Time: A Relativity Question"?

"Photon Experiencing Infinity Over Time: A Relativity Question" is a thought experiment that explores the concept of time dilation in special relativity. It involves a photon traveling at the speed of light and experiencing an infinite amount of time while only a finite amount of time passes in the observer's frame of reference.

## 2. How does this thought experiment relate to relativity?

This thought experiment relates to relativity because it demonstrates the concept of time dilation, which is a key aspect of special relativity. It shows how time can appear to move at different rates for objects moving at different speeds, and how this is affected by the speed of light.

## 3. Is this thought experiment possible to observe in real life?

No, this thought experiment is purely hypothetical and cannot be observed in real life. It involves a photon traveling at the speed of light, which is not possible for any material object, and therefore cannot be observed or tested.

## 4. What are the implications of this thought experiment?

The implications of this thought experiment are that time is not absolute and can be affected by the speed of an object. It also highlights the bizarre and counterintuitive nature of special relativity, and how it challenges our traditional understanding of time and space.

## 5. How does this thought experiment contribute to our understanding of the universe?

This thought experiment contributes to our understanding of the universe by helping us to grasp the concept of time dilation and how it relates to the speed of light. It also challenges our notions of time and space and encourages us to think about the universe in a more abstract and complex way.

• Special and General Relativity
Replies
1
Views
420
• Special and General Relativity
Replies
41
Views
3K
• Special and General Relativity
Replies
35
Views
3K
• Special and General Relativity
Replies
32
Views
1K
• Special and General Relativity
Replies
23
Views
2K
• Special and General Relativity
Replies
17
Views
578
• Special and General Relativity
Replies
51
Views
2K
• Special and General Relativity
Replies
11
Views
1K
• Special and General Relativity
Replies
11
Views
777
• Special and General Relativity
Replies
8
Views
923