Recent content by Sorao

A laser pointer can spot a point sharply at a screen 10m ahead. But it can’t spot a point 100m ahead because the beam diverges and brightness of the spot decreases. This is because of diffraction. Additionally, because of strong tidal effect, the divergence must be accelerated. So, I think all...

All I wanted to say is that eq. (7) seems simple enough to convince me.

“Kruskal–Szekeres coordinates“ shows that light can cross the event horizon. But, I think, the crossing can take place after the end of our spacetime. I calculated the time for light to reach the surface of a black hole from a certain point by simply integrating well-known equation. It went...

"dip" is impossible. Anything inside the EH can not go out of the EH. This is the definition of EH. Furthermore, I think, anything can not go into the EH in our (= observers far from the black hole) frame of reference because progress of the time stops there. Following link shows further...

If you go nearer and nearer to the event horizon, the effect of gravity gets stronger and stronger unlimitedly. So, I think, you can always find balancing radius for a photon to orbit a black hole. But, light as wave diffuses by diffraction. So, it will not last long.

I agree with this. All so-called black holes, I think, must be called quasi-black holes. Furthermore, if a black hole is formed from a chunk of dust, I think, time dilation also prevents the dust from falling further before becoming a genuine black hole because time dilation is larger at the...