A brilliant jet of high-energy particles shoots away from a quasar in this artist's concept. The quasar, ULAS J1120+0641, is a disk of super-heated gas spiraling into a black hole roughly two billion times as massive as the Sun. The energy from the disk makes the quasar outshine an entire galaxy of normal stars, even though the disk is only a few times the diameter of our solar system. Quasars are the most powerful sustained objects in the universe. This one is so far away that astronomers see it as it looked 13 billion years ago, when the universe was less than one billion years old. [ESO/M. Kornmesser]
Despite what we see in the movies, there aren’t many “Eureka!” moments in science — moments when a single discovery unlocks a big secret. Yet one such moment came 50 years ago today. It soon led to the astonishing truth about some of the most powerful objects in the universe.
At the time, astronomers were perplexed by objects known as quasi-stellar radio sources. They produced enormous amounts of radio waves, yet they looked like ordinary stars.
But when astronomers looked at such a star’s spectrum — its individual wavelengths of light — it wasn’t star-like at all. There were none of the usual “fingerprints” of chemical elements found in stars. That left a puzzle: What could produce so much radio energy, look like a normal star, but not be a normal star?
In 1962, astronomer Maarten Schmidt looked at one of these objects with the 200-inch telescope at Palomar Observatory in California. And in February of 1963, he realized something astonishing: The object’s spectrum did contain the fingerprints of chemical elements, but they were shifted to longer wavelengths — most likely by the object’s motion through space. The shift was so large that the motion was probably caused by the expansion of the universe itself. That meant that an object that looked like a single star was about two billion light-years away — giving it the power of hundreds of billions of stars.
But it took a bit longer to understand the source of that power — the power of a quasar. More tomorrow.
Script by Damond Benningfield, Copyright 2012
For more skywatching tips, astronomy news, and much more, read StarDate magazine.