Hints: galaxy NGC 1068 Dresslar Andromeda spectroscope

By measuring how fast these stars were moving, he could prove if there really was a black hole at the center of an active galaxy.
I picked a galaxy nearby which is called NGC 1068, an active galaxy, which meant that it probably had a supermassive black hole in it, at least, that's what we wanted to prove.
To be certain that the stars were moving unnaturally fast in NGC 1068, Dresslar wanted to compare them with stars in a normal galaxy without a black hole. Stars circling around a weak center of gravity would move at half the speed. So for this comparison, he chose the very ordinary galaxy next door to us, Andromeda, with a quiet, inactive center like our own.
To measure the speed of the stars in these two very different galaxies, Dresslar used an instrument called a spectroscope. This looks at the changing pattern of light coming from stars as they rotate around the galaxy core.

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