Time, gravity, and photons.

"A representation of the evolution of the universe over 13.77 billion years. The far left depicts the earliest moment we can now probe, when a period of "inflation" produced a burst of exponential growth in the universe. (Size is depicted by the vertical extent of the grid in this graphic.) For the next several billion years, the expansion of the universe gradually slowed down as the matter in the universe pulled on itself via gravity. More recently, the expansion has begun to speed up again as the repulsive effects of dark energy have come to dominate the expansion of the universe." (NASA, Universe Expansion Funnel)

When people say that time stops in photons, they mean that a photon delivers as much energy as it gets. So the photon itself has no time. But a photon's time is bound with the universe. This means that the age of photons is connected with the universe’s existence. 

The thing is that in the young universe, energy levels and scattering effects were stronger than in the modern universe or the universe where we live. The speed of light is a cosmic constant that depends on the environment. The speed of light is higher outside the atmosphere than in water or gas. 

The distance of particles and energy level, which means the power of the radiation, determines the speed of light. And the photon's speed is always the top. Because the speed of light always increases because of the weaker quantum fields and growing distance between particles, that means the photon's speed accelerates. And then we must understand that the other particles' speed compared to the photon’s speed is the same as in the past. When the entirety’s speed rises, the speed between objects seems the same. 

When we think about claiming that the universe expands faster than light, we can say yes and no. The fact is that the speed of light in the modern universe is higher than in the young universe. So there is a possibility that in the modern universe particles can travel faster than photons traveled in the young universe. But still, those other particles’ speed is lower than the photon's speed. The expansion of the universe causes light to travel faster. But because all other particles also travel faster than that, it is hard to see. 

"An illustration (not to scale) of a primordial black hole growing to supermassive size. (Image credit: Robert Lea (created with Canva))" (Space, Tiny ‘primordial’ black holes created in the Big Bang may have rapidly grown to supermassive sizes)

The other point is that. When a photon travels out from the universe, its speed should increase. But then the gravity of the entire universe pulls the photon back. It's hard to determine how fast a photon travels outside the universe. When a photon travels outside the universe, that means the universe pulls a photon into it with its entire mass. If the photon is in the universe, there is less mass behind it than outside the universe. 

In the same way, when we are at the edge of planet Uranus’s atmosphere, the gravity seems very strong. But when we drop to the surface of the stone shell or lithosphere of that planet, we face a situation where gravity is weaker than on Earth. The same way the universe can act when something is outside it. 

 When a black hole is behind a photon, that thing pulls the photon back to it. The massive gravitational effect also pulls the wave movement longer. This means that there is a possibility that the universe would be quite hard to see outside. But that is only speculation. 

The oversized black holes can form from tiny primordial black holes in the young universe. In the young universe, those black holes were closer to each other. And that caused a situation in which they collide more often than in the modern universe. 

When we think about enormous black holes in the young universe, we must realize that those black holes formed in conditions where the energy level was higher than in the modern universe. That means energy, or quantum fields, press against a black hole more powerfully than in the modern universe. That allowed the black holes to grow to an enormous size. Those black holes could form in a whirl in the powerful radiation. And when the universe expands, maybe those black holes' event horizons grow.

When the quantum fields turn weaker, that means the black hole starts to send radiation. That radiation can cause gravitational waves. The expansion of the universe can be one of the reasons why black holes sometimes separate from their material disks. And that causes the gravitational wave bursts. The expansion of the universe causes energy to move throughout the universe. And that thing is one of the things that causes the effect called time.

https://www.cfa.harvard.edu/news/over-massive-black-hole-young-universe

https://www.iflscience.com/are-those-eerie-oversized-black-holes-in-the-early-universe-the-result-of-direct-collapse-74341

https://svs.gsfc.nasa.gov/12314

https://www.space.com/astronomy/black-holes/tiny-primordial-black-holes-created-in-the-big-bang-may-have-rapidly-grown-to-supermassive-sizes