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Homework Help: Newton's Law of Gravitation

  1. Nov 2, 2003 #1
    According to Newton's Law of Gravitation, all objects with mass attract one another. This law implies that all of the atoms that make up a star, such as our sun, are gravitationally attracted to one another. How is a star able to resist collapsing under its own gravitational attraction?


  2. jcsd
  3. Nov 2, 2003 #2
    How is a table able to resist an apple falling through it if you put the apple on the table? There are interactions between matter other than gravitational forces.
  4. Nov 3, 2003 #3
    There are numerous interactions that counteract gravity, preventing such a collapse. In our sun, the process of nuclear fusion creates large amounts of heat and radiation; this radiation pressure keeps the star in equilibrium. In stars like white dwarfs, something called electron degeneracy pressure keeps the star from collapsing. This is a quantum effect that restricts the number of electrons we can squish into a certain volume, and acts to keep them apart. In neutron stars, a similar pressure arises from neutron degeneracy.
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