12 ms·

Wow, so it's currently shining purely from gravitational energy release, not nuclear reactions. I hadn't realized that it was possible or that we'd be able to s

• Sharlin 1y ago
  This was how physicists hypothesized the sun and other stars work in the late 19th and early 20th century, before the discovery of nuclear fusion. It presented a conundrum because calculations showed that the sun could only sustain the observed rate of energy release for a few million years – whereas the contemporary geological evidence was indicating that the Earth must be billions of years old.
• ByThyGrace 1y ago
  What is "gravitational energy release"? How does that lead to light emission (I suppose heat is generated in the middle)?
  • mattashii 1y ago
    The mass of a star was at some point a nebula, which collapsed into the star. That collapse reduced the gravitational potential energy of the mass of that nebula, which through accelleration, friction, and pressure, was turned into heat energy. That heated mass will emit black-body emissions, and so the gravitational energy is now being radiated as light.
  • teamonkey 1y ago
    Yes, heat through pressure and friction as the matter tries to collapse under gravity. Not quite enough heat and pressure to trigger a sustained fusion reaction. One interesting thing is that this star was detected at visual wavelengths, not infrared. While not undergoing fusion, it’s hot enough to glow blue-white.