Hitting the Books: The First To Hear The Birth Of The Stars

If the efforts of the more than 10,000 people who developed and assembled the James Webb Space Telescope are any indication, the age of the independent scientist is already over. Newton, Galileo, Kepler, and Copernicus fundamentally changed mankind’s understanding of our place in the universe, and did so on their own, but with the formalization and professionalization of the field in the Victorian era, these events occurred to an amateur astronomer using much rarer homebrew equipment.

In his new book, The hidden world: why there is actually more than meets the eyeMatthew Bothwell, a general astronomer at the University of Cambridge, tells the story of how we discovered an entire universe previously unseen outside of humanity’s natural scenery. In the excerpt below, Bothwell recounts the exploits of Grote Reeber, one of the world’s first (and only for a while) radio astronomers.

Oneworld publishing

Excerpts with permission From The Invisible Universe by Matthew Bothwell (one world 2021).

The only radio astronomer in the world

It’s a bit strange to look back at how the astronomical world reacted to Jansky’s findings. In hindsight, we can see that astronomy was about to be turned upside down by a revolution at least as large as the one initiated by the Galileo telescope. The discovery of radio waves from space marks the first time in history that humanity has glimpsed the vast invisible universe, hiding behind the narrow window of the visible spectrum. It was a momentous occasion that was almost overlooked in academic astronomy circles for one very simple reason: the world of radio engineering was so far removed from the world of astronomy. When Jansky published his initial results, he tried to bridge the gap, spending half the paper giving his readers a crash course in astronomy (explaining how to measure the position of objects in the sky, and why exactly the signal repeats every twenty-three hours and fifty-six minutes means something interesting). But in the end, the two systems suffered from a failure to communicate. The engineers spoke the language of vacuum tubes, amplifiers, and antenna voltages: incomprehensible to scientists who used to talk about stars, galaxies, and planets. As Princeton astronomer Melvin Skellett later said:

The astronomers said, “That’s interesting – do you mean there is radio stuff coming from the stars?” I said, “Well, that’s what it looks like.” ‘so interesting.’ And that’s all they had to say about it. They had to believe anything from Bell Labs, but they saw no benefit in it or any reason for further investigation. It was so far out of their way of thinking about astronomy that there was no real interest.

After Jansky moved on to other problems, only one person was interested in listening to radio waves from space. For about a decade, from the mid-1930s to the mid-1940s, Grote Reeber was the world’s only radio astronomer.

The story of the Grote Reber is unique in all of the science of the 20th century. He single-handedly developed an entire field of science, taking on the task of building equipment, making observations, and exploring the theory behind his discoveries. What makes him unique is that he did all of this as a complete hobbyist, working on his own outside of the scientific establishment. His job, designing electrical equipment for radio broadcasts, gave him the skills to build his telescope. His fascination with the scientific literature put him in touch with Jansky’s discovery of static planets, and when it became clear that no one else in the world cared much, he took it upon himself to invent the field of radio astronomy. He built his telescope in his back garden in Chicago using equipment and materials available to anyone. His telescope, about ten meters wide, was live talk (and for good reason – it looks a bit like a doomsday cartoon). His mother used it to dry her laundry.

He spent years scanning the sky with his homemade instrument. He observed using his telescope all night, every night, while he was still working at his day job (apparently he slept a few hours in the evening after work, and again at dawn after finishing the telescope). When he realized that he did not know enough physics and astronomy to understand the things he was seeing, he took courses at the local university. Over the years, his observations have painted a beautiful picture of the sky as seen by radio. Discover the sweep of our Milky Way, with bright spots in the galactic center (where Jansky picked up his fixed star), and again toward the constellations Cygnus and Cassiopeia. By this time he had learned enough physics to make scientific contributions as well. He knew that if the cause of the hissing from the Milky Way was thermal emission – thermal radiation from stars or hot gas – it would be stronger at shorter wavelengths. Given that Reber was picking up much shorter Jansky wavelengths (60 centimeters, compared to Jansky’s fifteen-meter waves), Reber was supposed to be bombarded with invisible radio waves tens of thousands of times more powerful than anything Jansky had seen. But it wasn’t. Reber was confident enough in his instrument to conclude that whatever the cause of these radio waves, they must be ‘non-thermal’ – that is, they were something different from the radiation of the ‘hot, glowing stuff’ we discussed back in Chapter 2. He even suggested the (correct!) solution: the hot interstellar electrons swaying through an ion – a positively charged atom – would roll like a Formula 1 car taking a tight angle. The bent electron will emit a radio wave, and the combined effect of billions of these events is what Reaper discovered from his back garden. This only occurs in hot gas clouds. It turns out that Reber was picking up radio waves emitted from clouds containing newborn stars scattered throughout our galaxy. He was, quite literally, listening to the birth of stars. It was a sound no human had heard before. To this day, radio observations are used to track star formation, from small clouds in our Milky Way to the birth of galaxies in the farthest corners of the universe.

In many ways, Reaper’s story seems like an anachronism. The golden age of independent scientists, who were able to make groundbreaking discoveries by working on their own with homemade equipment, was hundreds of years ago. With the passing of the Victorian era, science became a complex, expensive and above all professional business. Grote Reber, as far as I know, is the last of the “outsider” amateur scientists. The last person who did not receive any scientific training, built his own equipment in his garden, and through hard and meticulous work was able to change the scientific world.

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