I love it when scientists discover something unusual in nature. They have no idea what it is, and then over decades of research, evidence builds, and scientists grow to understand what's going on. My favorite example? Quasars. Astronomers first knew they had a mystery on their hands in the nineteen-sixties (1960s) when they turned the first radio telescopes to the sky. They detected the radio waves streaming off the Sun, the Milky Way and a few stars, but they also turned up bizarre objects they couldn't explain.
These objects were small and incredibly bright. They named them quasi-stellar-objects or "quasars", and then began to argue about what might be causing them. The first was found to be moving away at more than a third the speed of light. But was it really? Maybe we were seeing the distortion of gravity from a black hole, or could it be the white hole end of a wormhole. And If it was that fast, then it was really, really far... 4 billion light years away. And it generating as much energy as an entire galaxy with a hundred billion stars. What could do this?
Here's where Astronomers got creative. Maybe quasars weren't really that bright, and it was our understanding of the size and expansion of the Universe that was wrong.
Then in the 1980s, astronomers started to agree on the active galaxy theory as the source of quasars. That, in fact, several different kinds of objects: quasars, blazars and radio galaxies were all the same thing, just seen from different angles. We now know that all galaxies have supermassive black holes at their centers; some billions of times the mass of the Sun. When material gets too close, it forms an accretion disk around the black hole.
It heats up to millions of degrees, blasting out an enormous amount of radiation. The magnetic environment around the black hole forms twin jets of material which flow out into space for millions of light-years. This is an AGN, an active galactic nucleus. When the jets are perpendicular to our view, we see a radio galaxy. If they're at an angle, we see a quasar.
In 10 billion years or so, when the Milky way collides with Andromeda, our supermassive black hole may roar to life as a quasar, consuming all this new material.
