If Light Has No Mass, then why is It Affected by Black Holes
According to General Relativity. A photon always travels by the shortest distance between the two points, and around a black hole, the distortion of space-time is extreme. So light(Photon) is appear to be bend around the black hole. As a space-time wrap around a massive object light seems to be bend around it.
In a more simple way photon is not fall off inside the black hole, but it just cover its own shortest distance trajectory.
The illustration diagram is given below for more understanding,
Source:
[1] Pandian, Jagadheep D. “If Light Has No Mass, Then What Draws It into a Black Hole? (Intermediate) – Curious about Astronomy? Ask an Astronomer.” Cornell.edu, 2015, curious.astro.cornell.edu/physics/86-the-universe/black-holes-and-quasars/general-questions/433-if-light-has-no-mass-then-what-draws-it-into-a-black-hole-intermediate. Accessed 1 July 2021.
[2]https://onheaven.co.in/2020/11/02/the-key-points-about-black-hole/
[3] More from this author. “If Light Has No Mass, Why Is It Affected by Black Holes?» Science ABC.” Science ABC, 15 Jan. 2016, https://www.scienceabc.com/nature/universe/if-light-has-no-mass-why-is-it-affected-by-black-holes.htmlAccessed 1 July 2021.