1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Black Holes Gre.67

  1. Nov 30, 2003 #1
    Black Holes Gre.67
    67. A black hole is an object whose gravitational field is so strong that even light cannot escape. To what approximate radius would Earth (mass = 5.98 x 10^24

    kilograms) have to be compressed in order to become a black hole?
    a. 1 nm
    b. 1 microm
    c. 1 cm
    d. 100 m
    e. 10 km

    the answer is C.
  2. jcsd
  3. Nov 30, 2003 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    [tex]r_s = \frac{2 G M}{c^2}[/tex]

    - Warren
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook