Moving Out of Town

In This Chapter

V Distant galaxies, strange galaxies

V Active galaxies: Seyfert and radio galaxies

V What drives an active galaxy?

V Galactic jets

V What's in a quasar?

Remember Grote Reber? He's the man who, back in 1936, built a radio telescope in his backyard, and by the 1940s had discovered the three brightest radio sources in the sky. He didn't know it at the time, but two of them—the Galactic center, Sagittarius A; and the shrapnel of a supernova explosion, Cassiopeia A—are sources in our own Galaxy. But the third radio source, called Cygnus A, turned out to be much, much farther away. And far more strange.

In 1951, Walter Baade and Rudolph Minkowski located a dim optical source at the position of Cygnus A and, from its spectrum, measured a redshift (or its recessional velocity) of some 12,400 miles per second (almost 20,000 km/s). Whatever it was, Cygnus A was moving away from us—fast! For a while, astronomers tried to figure out how an object in our galaxy could be moving so fast. It turns out it wasn't in our galaxy at all, but very far away. Later, astronomers would discover that this was something never before seen: a distant inferno churning out the energy of a hundred normal galaxies.

In this chapter, we will examine objects like Cygnus A and the other monsters that hide deep in the hearts of distant galaxies. They are some of the most energetic and bizarre objects in the universe.

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