From nearly winning the Nobel to farming in Italy
IT WAS TWENTY YEARS AGO TODAY…
Apologies to the Beatles, but it was twenty years ago in January 1990, that Herb Gush, a physicist at the University of British Columbia, performed a landmark measurement of the cosmic microwave background using a rocket-based experiment. Had fate sided with him and had he launched the rocket a few months earlier, Gush would have won the Nobel Prize for accurately measuring the spectrum of the CMB. Instead, he became the first to independently confirm the measurements made by NASA’s Cosmic Background Explorer (COBE) satellite, for which John Mather and George Smoot won the Nobel in 2006.
The same month that Gush launched his rocket from White Sands, New Mexico, John Mather received a standing ovation at the meeting of the American Astronomical Society in Crystal City, Virginia. His experiment on COBE had shown that the radiation leftover from the big bang had exactly the spectrum expected of black-body radiation. It was a stunning confirmation of the big bang theory.
Gush almost beat Mather to the first indisputable measurement of the CMB spectrum (after the initial discovery by Penzias and Wilson in 1965). Gush had been using rockets to launch spectrometers hundreds of kilometers into space since the 1970s. But his earlier attempts with prototype spectrometers were unsuccessful as the payload failed to stay clear of the rocket’s exhaust, messing up the measurements.
Then , in the late 1980s, Gush and graduate students Ed Wishnow and Mark Halpern were ready with a sophisticated instrument that compared the CMB spectrum with the spectrum of an on-board blackbody radiator. But in the fall of 1989, the device was damaged by the malfunctioning of a vibrator in a vibrator test before launch.
The time it took for repairs meant that the rocket launch was delayed until late January 1990. When it was finally sent up, the experiment was a success. “It was immediately clear that the spectrum was near Planckian with a temperature near 2.7K,” said Gush in an email to me in 2007.
But as luck would have it, COBE had already made the measurement. If the roles had been reversed, COBE would have confirmed Gush’s data and not the other way around. Of course, this doesn’t take anything away from COBE, which was an exquisite experiment.
Just goes to show how small the margin can be between being the first to a discovery and the second.
Gush, for his part, retired and took up farming near Palermo, Italy.
When I met cosmologist James Peebles of Princeton in 2007 for my book The Edge of Physics, Peebles was still a bit miffed that Gush didn’t share the Nobel with Mather and Smoot. “There should be a list of great measurements that were underappreciated,” he told me. “Gush was working on that experiment for more than 15 years. COBE was under development for the same length of time, and they got first data within 2 months of each other. Mather in his book is very explicit – Gush could have scooped us, and would have been famous. Instead young people don’t even know his [Gush’s] name.”
Well, here’s to Gush and his brilliant experiment.