How Did Black Holes Grow So Large? Gravitational Waves Know
Your galaxy has a supermassiv black hole - so does mine as does every large galaxy.
But how did they grew so big is a matter of speculation.
Einstein predicted gravitational waves; ripples in space-time, generated by bodies changing speed or direction. Bodies, for instance, such as pairs of black holes orbiting each other. When galaxies merge, their resident central black holes are doomed to meet. They first waltz together then enter a desperate embrace and merge. Towards the end of this dance they're sending out gravitational waves at a frequency we can detect and played out again and again…