Happy Birthday, Grote Reber!

Grote Reber (December 22, 1911 - December 20, 2002), the American electrical engineer who pioneered radio astronomy using his 9.5-meter dish-shaped telescope.

Every time someone discovers a new way of seeing, we discover something new to see. Today would be the 100th birthday of electrical engineer Grote Reber (1911-2002), who built the first dish-shaped radio telescope. Karl Jansky built the first radio telescope, which looks more like the Wright Brothers’ flier than our usual conception of a telescope, and found diffuse radio emissions from the Milky Way. Reber applied for a job to work with Jansky, but since it was the middle of the Great Depression, nobody was hiring…so Reber built his own telescope in his back yard in Wheaton, Illinois. Just in case you were feeling you haven’t accomplished anything today.

Radio emission from synchrotron sources in the Milky Way, as mapped by Grote Reber in the 1940s.

Reber’s first telescope was 31.4 feet in diameter (about 9.5 meters), which is pretty significant. (The radio telescope we used in the class I taught at Rutgers is only 3 meters.) He had to adjust the receiver until he found a frequency that actually worked for detecting radio waves from space, but once he did, he was able to begin mapping the Milky Way in radio light. The image on the left shows some of his early data from bright radio sources. In later years, Reber worked in Hawaii and ultimately settled in Tasmania, where he died in 2002, just shy of his 91st birthday.

Reber was the first to see radio from supernova remnants in Cassiopeia, though it was several years before other scientists figured out the explanation for them. The mechanism is synchrotron radiation: radio waves emitted by electrons that have been accelerated nearly to light-speed by strong magnetic fields. Today, observing synchrotron radiation is routine, showing yet again how cutting-edge science in the past becomes normal.

It’s good to remember the origins of these discoveries, not least since Reber was an amateur astronomer in the colloquial sense, but also in the literal sense. He did what he did out of love of science and knowledge. To me, “amateur” isn’t an insult at all, any more than “citizen science” is inferior to “professionals” (and I’m not saying that just because as an unemployed writer, I’m technically “amateur” myself). Today’s amateur astronomers look for comets, near-Earth asteroids, and help in the search for exoplanets.

Grote Reber's radio telescope, now at NRAO in Green Bank, West Virginia.

So happy birthday, Grote Reber! If you get a chance, go see his telescope at the National Radio Astronomy Observatory (NRAO) in Green Bank, West Virginia, and imagine it sitting in a geeky 20-something’s back yard in the 1930s, discovering something new about the cosmos.



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