Exploring Black Holes: Part 2

The Care and Feeding of Black Holes

How intrinsically invisible objects become the brightest things in the universe

Part 2 of a four-part series on black holes. Part 1 can be found here.

The quasar poetically known as GB 1428 in visible, radio, and X-ray light. This object is more than 12 billion light-years away but is bright enough to be seen from Earth. That’s because it’s powered by a supermassive black hole. X-ray: NASA/CXC/NRC/C.Cheung et al; Optical: NASA/STScI; Radio: NSF/NRAO/VLA.

In the late 1950s, astronomers began spotting a number of bright sources of radio waves and visible light. These sources were pinpoints resembling blue stars, but further investigation showed they had to be something very different. For one thing, these quasi-stellar objects, as they were known then, were extraordinarily distant, much farther than any single star would be visible.

The spectra of these new quasi-stellar objects, or quasars, as physicist Hong-Yee Chiu abbreviated their name in 1964, showed they were emitting light through a completely different mechanism than starlight. The quantity of light quasars emitted to be visible across the universe meant they had to be driven by gravity.

Based on the data, astronomers concluded that each quasar was powered by a black hole millions or billions of times the mass of our sun. These supermassive black holes pull huge amounts of matter onto themselves, accelerating it until it glows very brightly. Additionally, the black hole jets a lot of matter away from itself rather than eating…