A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

If photons do not have mass (mass =0), then how are they captured by black holes? OR in other words how strong gravity can bend light rays?

  • This Question is Open
  1. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    photon has rest mass zero ... it has some mass during motion ...

  2. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    A photon has mass, irrespective of its state of motion ... but the mass is relatively negligible. so, in other words.. the light doesn't itself means photons.. cause light is a electromagnetic thing that comes from this photon particle.. when the so called black hole's gravity makes the source of light to bend it towards (as they say so) so does the emission of light seems to be bend.

  3. deltanu
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 0

    It's actually more subtle than that... Photons are, as far as physicists know, massless particles (m=0). They have an associates energy and momentum though, but these are relativistic properties, not like p=mv or K=1/2mv^2. If you read Prof Shankar's chapter on relativity he explains this well. Anyway, to cut a long story short, you need general relativity to explain why gravity bends light. Gravity actually BENDS SPACE so that light naturally travels along lines that appear 'curved'. So even a particle with no mass has to follow these lines (called geodesics). Check out this youtube vid it's mindbendingly awesome: https://www.youtube.com/watch?v=vNaEBbFbvcY

  4. deltanu
    • 11 months ago
    Best Response
    You've already chosen the best response.
    Medals 0

    *associated energy and momentum

  5. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.