It is hard to imagine the thoughts of Grote Reber’s neighbors when he built a 10-meter-wide bowl of sheet metal in his yard, perched on a scaffold that could be adjusted and topped with a pyramid of gangly towers. His neighbors didn’t know that they were witnessing a new way to look at the cosmos.
Reber was responsible for the creation of the first radio telescope. Contrary to traditional telescopes that use mirrors or lenses to focus visible light, the contraption uses metal and circuitry to collect interstellar radiation waves, low frequency ripples, and electromagnetic radiation. With his homemade device, Reber made the first map of the sky as seen with radio-sensitive eyes and kicked off the field of radio astronomy.
Karen O’Neil (site director, Green Bank Observatory in West Virginia) says that radio astronomy is just as important to our understanding the universe as optical astronomy. “If we are to understand the universe, it is essential that we have as many eyes as possible.”
Astronomers don’t refer to radio waves from space when they talk about alien broadcasts. They are more interested in the low-energy light that can be produced when molecules rotate or electrons swirl within a magnetic field. Tuning in to interstellar radio waves for the first time was akin to Galileo pointing a modified spyglass at the stars centuries earlier — we could see things in the sky we’d never seen before.
Radio astronomy has become a global business. There are more than 100 radio telescopes scattered around the globe, ranging from tiny antennas that sit low to the ground to gigantic Reber dishes that span hundreds of metres. These eyewitnesses have been so revolutionary that they have won no less than three Nobel Prizes.
It’s not bad for a field that was accidentally started.
Karl Jansky, an engineer from Bell Telephone Laboratories was searching for radio waves that could interfere with wireless communication in the 1930s. He stumbled upon a hiss coming from somewhere in the constellation Sagittarius, in the direction of the center of the galaxy.
Jay Lockman, an astronomer also from Green Bank, says that the basic discovery of radio radiation coming out of interstellar space confused theory. “There was no way to get that.”
Jansky was moved by Bell Labs to pursue other, more earthly pursuits. Reber, who is a lover of all things radio and read about Jansky’s discovery, wanted to learn more. Reber was the first person to build a radio telescope. He used principles that focus visible light from optical scopes to design his own. Jansky’s antenna, which consisted of a series of metal tubes supported by a pivoting wooden tripod, was his inspiration. Reber created a parabolic dish made from metal to focus radio waves at a specific point. An amplifier amplified the weak signal. The entire contraption was positioned on a tilting wooden platform that allowed him to scan the sky with the telescope by moving it up and down. Radio telescopes around the globe use the same design.
Reber was almost completely alone for nearly a decade, thanks to the Great Depression as well as World War II. After the war, however, the field was not thriving. There were a few scientists who had new radio expertise and could design radar systems. Since then, surprises have continued to surprise.