I was talking with my friend about blackholes and I asked him "Why blackhole 'sucks' the photons?"

He had no deeper understanding so he answered that "I dont know, may the light is affected, because blackhole affects the volume of space (dont know better translation)", so I am asking you:

  1. Is that some gravitational coexistence? (but photon has no mass)

  2. Is the photon directly "sucked" into blackhole?

  3. Can we measure mass of blackhole?

Have a nice day!