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

I heard that if you took a peice of the sun the size of a pinpoint

  1. Apr 13, 2008 #1
    that it would burn everying in a 90 mile radius, or something like that, is this correct? Would this be the same as if the equivelant amount of hydrogen atoms fused all at once together?
  2. jcsd
  3. Apr 13, 2008 #2
    It doesn't sound right, where did you hear this?

    You could have quite a bit of hydrogen in the size of a pin point if you compressed and cooled it, but I still don't think you would have enough to create a blast with a 90 mile radius on earth.
  4. Apr 13, 2008 #3


    User Avatar
    Staff Emeritus
    Science Advisor

    That doesn't sound right.

    One can do a simple calculation based on a hydrogen plasma with the density of water, about 1 g/cm3, which is a little less than the average density. Multiply the density by the volume of a pin point to get the mass, and figure some appropriate temperature.

    The sun is based on the pp-chain, and p-p fusion is very slow, say compared to d-d fusion, and that's why the sun has been around for a long time.

    Bear in mind that the core of the sun is on the order of 15 million K, and its density if about 150 times that of water. In contrast, the photosphere has a temperature of about 5800 K and a density on the order of 1E-7 of water (at room temp).
  5. Apr 14, 2008 #4
    I believe this figure results if you assume that the pinpoint (I suppose the head of a pin was meant) will magically stay at 15 million K, even when radiating such an enormous amount of energy.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook