Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Question about black holes and white dwarf

  1. Jun 24, 2010 #1
    i want to ask aquestion
    what is the biggest qatar:
    black hole or white dwarf or nutron star or the sun
    please i want to know the biggest one and then and then and the smallest one
    thaaaank you very much
  2. jcsd
  3. Jun 24, 2010 #2


    User Avatar
    Science Advisor
    Homework Helper

    Well the word "qatar" doesn't make any sense, but it is clear what you are asking.

    The sun is about 100 times as big (in diameter) as earth

    A white dwarf is roughly the same size as the earth, depending on its mass.

    A neutron star is about the size of a city, 10-15 km in radius.

    A black hole can be any size, depending upon its mass.
  4. Jun 24, 2010 #3
    I'm guessing he means either quark-star, or quasar.

    Hager Mahdy, if you did mean Quasar, they are believed to be the active nuclei of distant galaxies, and therefore are black holes. If you meant Quark-Star (possibly a step between Neutron Star and Black Hole) then no one knows, but it would be more compact than the former, and less so than a black hole.

    Remember that a black hole is best defined by its event horizon, which is purely a function of its mass, as Nicksauce said. They seem to get quite massive, especially AGNs.
  5. Jun 27, 2010 #4
    thank you very much and iam sorry but i mean diameter
    thaank you
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook