Einstein's Theory of Relativity to Measure Mass of a White Dwarf

Stein 2015B : Hubble Space Telescope Images

     Astronomers used Einstein's old general theory of relativity to measure the mass of white dwarf by its light.

In 1915 Einstein's general theory of relativity explains the wrap space and its gravity. Astronomers use this effect to measure the position and mass of distant galaxies. Hubble observed a tiny dwarf called Stein 2015B which pass in front of the star. Using its images from Hubble scientists calculated that the white dwarf is 68 percent of our Sun's mass. Astronomers measured the deflected light and found that the white dwarf is 400 times brighter than the background star. Stein 2015B is 17 light years away from Earth and it is 2.7 billion years old. The background star is 5000 light years away.

References: Stein 2015B Hubble Space Telescope