I’m generally not a fan of the Nobel Prize. Mostly because I feel it perpetuates the myth of “genius” and discredits the hard work of a bunch of people all working together to accomplish something great.
It also could be because I never seem to win one.
Be that as it may, October has been a good month for Nobel prizes in astronomy. Two of my colleagues, Michel Mayor and Didier Queloz, shared this year’s prize for being the first people to discover a planet orbiting another star.
In the early ’90s, despite multiple Star Trek series’ theorizing otherwise, we didn’t know definitively of any other planets outside our own solar system. Sure, we astronomers argued they had to be there, but no one had yet found them. A few years later, observers detected the hint of low-mass companions to a neutron star, but that was a far cry from the Earth-like worlds the starship Enterprise kept visiting.
But in 1995, all of that changed. Two Swiss astronomers, the aforementioned Mayor and Queloz, detected the signature of a planet orbiting a sun-like star.
I say signature because, like looking for a firefly next to a streetlight, due to the star’s brightness, any planets are impossible to see directly. Instead we rely on the slight gravitational tug of the planet on its host star and measure the resulting wobble of the star itself. The larger the size of the planet, or the closer the planet orbits the star, the bigger the wobble.
As the observational technology improved, quite a few astronomers were looking for what came to be known as exoplanets. Most felt this had to be a multi-year, and possibly multi-decade, effort, since a planet large enough to be observable — something like Jupiter or Saturn — took at least that long to orbit the sun. Astronomers considered it a bit of a gamble to waste any time early in a career looking for them.
But here is where the “genius” of Mayor and Queloz came in. Their data, collected on the star 51 Peg, indicated a low-mass companion that was about half the mass of Jupiter, orbiting its star in four days.
To put that in perspective, tiny Mercury orbits the Sun in 88 days, and Earth takes 365. Jupiter doesn’t complete its orbit for nearly 12 years.
Scientists are trained to be skeptical, and it took some guts for the Swiss team to publish its work when everything we knew about solar-system formation suggested such “hot Jupiters,” as they came to be known, could not exist. Despite the fact that other researchers quickly confirmed the find, the planet’s existence was refuted until several other of these hot Jupiters were discovered. Now, in 2019, we have a catalog of over 4,000 exoplanets containing all sorts of new types of planets, with these close-orbiting Jupiters being some of the more common.
Mayor and Queloz were singled out not because they were the only team hunting for such objects, and perhaps not even because they were the most prolific. In the ensuing decade, that prize went to a team of American astronomers, who were guided by the Sputnik Principle: that which you do not do first, make up for in volume.
No, Mayor and Queloz were awarded the prize because they had the courage to make an extraordinary claim for which they had the data to support, despite everything we knew about how planetary systems worked.
That said, I’m sure both astronomers would agree they are hardly geniuses. They accomplished what they did through hard work, a bit of luck and a lot of support from their colleagues, institutions, taxpayers and the scientists and engineers who went before them to make their work possible.
It’s fun to recall that I was in my astronomy class when this discovery was made. I remember the day before evidence of exoplanets existed and the day after. Now we are looking for Earth-like planets that might harbor life like our own. I’m hoping pretty soon someone will find one, and we will be able to point to a place in the sky where other beings, perhaps like us, exist.