How do quasars affect us?

As quasars are extremely far away from us—millions to billions of light years away—their energy output is enormous, but it is negligible compared to what reaches Earth.

We would not be affected even if the supermassive black hole at the center of our galaxy were to explode as a quasar because it is more than 25,000 light years away.

Since quasars are so far away, they are essentially fixed points in space. Quasars are used as fixed reference points to help us determine the exact orientation of the Earth on January 1, 2000, 12:00:00, which is necessary to measure astronomical object positions with great precision. Object positions are typically defined in terms of the J2000 epoch.

Supermassive black holes power these incredibly bright, far-off celestial objects called quasars, which have little direct effect on Earth but can be studied to learn more about the early universe.