Did you just assume our genders?shivakumar said:
I don’t think that there is any need to restrict yourself to the time of collapse. For a formed black hole light is trapped at the horizon, it orbits at the photon sphere, and it is deflected at larger distances. So a U turn is just a large deflection, but less than an orbit. That means that at some distance above the photon sphere you should be able to make a null U turn for a stable black holeshivakumar said:
I think we may need to ask @shivakumar for clarification of what "U turn" means in this context. You seem to be imagining light falling from infinity and doing a half orbit. I was imagining light coming up from the star, turning back and falling on to the star/black hole again. Your scenario is possible, mine isn't (hence my longer explanation).Dale said:
Good point. Yes, that is what I was considering.Ibix said:
Please not also on PF...malawi_glenn said:
A "Light Taking U-Turn" refers to the phenomenon where light emitted from a star is bent back towards the star due to the intense gravitational pull of the star as it collapses into a black hole. This can be observed as a sudden increase in brightness before the star disappears from view.
A star transforms into a black hole when it runs out of fuel and can no longer sustain the nuclear fusion reactions that keep it stable. Without this outward pressure, the star collapses under its own gravity, becoming denser and denser until it reaches a point of infinite density known as the singularity, which is surrounded by the event horizon - the point of no return for anything, including light.
Yes, we can observe the transformation of a star into a black hole through various methods, such as detecting gravitational waves, observing changes in the star's brightness and spectrum, and studying the effects of the star's intense gravitational pull on its surroundings.
The time it takes for a star to transform into a black hole depends on the size and mass of the star. Generally, more massive stars will collapse faster, while smaller stars may take longer. This process can take anywhere from a few milliseconds to millions of years.
Light that gets trapped within a black hole cannot escape, as it is unable to travel faster than the speed of light. This is why we cannot observe anything beyond the event horizon of a black hole. The light is essentially stuck inside the black hole, adding to its mass and energy.