What if photon arrives before it leaves?

The idea of time dilation is an interesting thing. The time dilation means that when the energy level rises time slows on the object. The same way gravity acts on the objects near gravity centers. That makes the model possible that gravity pulls some fields to the gravity center. 

The field that travels to the gravity center makes objects "shine". Or, that pumps energy to them. This slows time in those particles. And that is one form of time dilation. 

Because those fields travel to the gravity center. They pump energy to the particles that are in the gravity pothole or near the gravity center.  Time dilation makes it possible that a photon can theoretically arrive before it leaves.

We can think of the crossing speed of light as the case where somebody throws the ball in an aircraft. If the speed of the ball is 15 km/h if measure is made in the aircraft. But if we measure that speed from outside the airplane it travels at 800 km/h. The speed of the ball is 815 km/h. Then we can transfer that example to the traveling fields. 

The light cone. The time stops when the speed of the particle reaches the speed of light. And turns the opposite. When a particle crosses the speed of light. The black hole's event horizon is the point where escaping velocity reaches the speed of light. Inside the event horizon, all particles travel at the same speed. If the field travels with the speed of light particles, that travel in the field can cross the speed of light outside the field. The field is space. And if the speed of space is the speed of light particles can travel in that space faster than light travels outside that field. 

Can a photon arrive before it leaves? 

In the cases. That photon arrives before it leaves. That would be hard to detect. The photon exists from the point where it is born. And the same way if something happens in the past that exists from that moment. So we cannot see if a photon forms before it arrives. But for us, the photon exists from the moment that we see it. And that causes a nice little paradox. The question is: can the photon that arrives before it is born collide with itself? If photon form before it arrives that can cause the quantum entanglement between those photons. But can a photon really make that thing? 

Again: can a photon arrive before it leaves? 

That requires that time turns to the opposite. That thing is not possible if the photon itself cannot cross the speed of light. In time dilation time turns to the opposite only if gravity turns the escape velocity higher than the speed of light. That means gravity is the thing that can turn time opposite only behind the black hole event horizon. Another case can be when the photon leaves in the cosmic void.

The point where the photon leaves from the photon source must be very close to the edge of the cosmic void. And when the photon travels with a speed. That is higher than the speed of light outside the void it can make that thing. Theoretically, that thing is possible when the photon travels from the cosmic void to the water. 

That can make it possible that time travels in photons backward when it impacts water. The impact energy can turn time opposite in photons so much that photon travels back in time. 

If that time reversion is strong enough. The photon can arrive before it leaves. In the real world, the cosmic void cannot be in a bubble of water. But there may be ice bite in cosmic voids. And when a photon hits that thing it can cause time reversion. 

The nature of time is interesting. The photon itself cannot have time. The problem is that the photon can cross the speed of light. But that must happen in space that is isolated from the space where light travels slower.  The speed of light is slower in water than in vacuum. It's impossible to create a space that combines those two spaces. The opposite time is possible only in cases where photon travels faster than light. 

The black hole pulls fields inside it, so there, the photon can travel faster than light travels outside the black hole's gravitational pothole. But the speed of light depends on the speed of space. And space is the energy field that takes photons with it. 

There is one hypothetical way to make a photon that crosses the speed of light. This requires that the photon is a ring-shaped superstring structure. The superstring that rotates very fast and then travels forward can theoretically make that thing. 

"Is time travel possible? Scientists and science fiction writers alike continue to imagine the possibilities. (Image credit: DKosig via Getty Images)" (Space.com, Time travel: Is it possible?)

But the photon cannot reach its target before it leaves in normal universe.

The photon can travel only at the speed of light. That is the speed of a photon. That is one of the cosmic constants. This means that the speeds that are below the speed of light the time dilation can affect only in particle's lifetime. So in normal spacetime, the limit of the time dilation is the photon's lifetime. 

There is also another thing that we must remember. The time dilation happens only on the particle's or object's surface. Or inside the object. That means outside observers might not see that thing happening. The problem with this kind of paradox is that. When something happens in the past. That thing has existed since that moment. 

So, if a photon can leave before it arrives that causes another interesting paradox. We can see the photon when it arrives. But a photon arrives before it leaves it can double itself. That means we cannot probably see when that happens. The photon exists when it leaves. And this means the photon that always leaves before it arrives pushes that event back in time. 

https://www.businesstoday.in/visualstories/news/a-photon-left-before-it-arrived-new-experiment-suggests-the-past-may-not-be-fixed-205958-30-01-2025

https://scitechdaily.com/a-revolutionary-new-physics-hypothesis-three-time-dimensions-one-space-dimension/

https://www.space.com/21675-time-travel.html

https://en.wikipedia.org/wiki/General_relativity

https://en.wikipedia.org/wiki/Time_dilation