If We Colonize a Neighboring Solar System, Thank Guillem Anglada-Escudé

The man who discovered Proxima Centauri b says he was inspired by sci-fi to search for other worlds for humans to colonize.

Nowadays, Guillem Anglada-Escudé can analyze telescope data for over 14 hours without so much as looking up. But as a kid growing up in Barcelona, he was "not much into math."

Sitting in his office at the School of Physics and Astronomy of Queen Mary University London, he tells me that it was only when he picked up Red Mars by Kim Stanley Robinson that he had his own personal eureka moment. Anglada-Escudé was 18 when he read this carefully researched scientific imagining of the first human colonization of Mars, and today he urges me to read it because "when I read this book I was like, yes! This is what I want to do."

This teenage inspiration resulted in the front cover of Nature magazine in the summer of 2016, announcing that Anglada-Escudé had reached a new frontier in astronomy and space colonization—he and his colleagues had discovered the closest potentially habitable exoplanet, named Proxima Centauri b, or "Proxima b," for short.

Artist's rendering of Proxima b

Artist's rendering of Proxima b. Image: ESO/M. Kornmesser

The first exoplanet was discovered in 1995, and since then over 2,000 planets outside of our solar system have been found. Yet the discovery of Proxima b , a rocky planet 1.3 times the size of Earth, is the one that has prompted excitement among dreamers and sci-fi fans across the world, and is fueling the space explorers of the very near future. Proxima b crucially sits within the so-called 'Goldilocks Zone" of its star Proxima Centauri, a red dwarf that is the Sun's closest neighbor at 4.25 light years away, which means it could support liquid water—and possibly life—on its surface.

However, Anglada-Escudé nonchalantly says that Proxima b "could have been found 15 years ago" and blames the ruthlessly competitive culture in astronomy leading to the race to find exoplanets becoming "very secretive without much advance in technique."

Anglada-Escudé took a maverick approach to exploring the skies surrounding Proxima Centauri, foregoing alignment with established research groups and instead meticulously studying publicly available data sets that had been collected using ground telescopes, also eschewing the current trend for finding exoplanets using data from the Kepler spacecraft.

"The data analysis part is fun," Anglada-Escudé says. "My expertise is trying to do things a bit better than other people have tried. I work in high precision. Getting all you can from the data." He realized that vast amounts of data had been "sitting in the archives, untouched", and developed an algorithm for measuring the velocity of the star. In 2012 signals started to pop up out of the data that told him Proxima Centauri could have a planetary system.

"This is very big. This is the nearest star to the sun, we had better get it right."

By then, he was pretty sure he had found it. But such a momentous discovery would be under intense scrutiny, especially in a field where recently there have been "a number of controversial claims, some by myself" Anglada-Escudé admits.

In 2014, this led to him withdrawing a paper on Proxima b, because he and his colleagues realized: "This is very big. This is the nearest star to the sun, we had better get it right." Then, in early 2016 from the European Southern Observatory in Chile, Anglada-Escudé observed Proxima Centauri for just fifteen minutes every night for two months, and with only one quarter of the data that he planned to gather he knew he had found it, which was "kind of a relief."

"There is always a race to find exoplanets. The race is now to see who can figure out which of these planets has an atmosphere" says Anglada-Escudé, explaining that technology is not yet sophisticated enough for us to actually visualize Proxima b , and that he is working to develop this.

"There is always a race to find exoplanets."

Anglada-Escudé believes that Proxima b is tidally locked, meaning one face is continually looking at the star, like our moon is to Earth. This is apparently "not a big issue for the planet being habitable."  He continues:

"But what is problematic is that the planet is very close to the star, twenty times closer than Earth is to the Sun. And these stars have flares like the sun, and so you have a factor of 100 times more radiation. It is a big question mark—how an atmosphere of such a planet will evolve over time, whether it can survive at all."

Anglada-Escudé believes that scientists have a responsibility to ask fundamental questions because "if people are not excited and it is not useful, then I do not know why you do things. I can just do it by myself at home." He acknowledges that the discovery of exoplanets will not change anything immediately, but cites space exploration as a driver for the invention of new technology, saying "the exoplanets are somewhere to go."

"Why would you design super precise instruments? It is boring," Anglada-Escudé says. "But then you realize that you can find planets like Earth, like the ones that you read about, like the ones I imagine. And that is huge."

Alongside characterizing the atmosphere of Proxima b, Anglada-Escudé is also working on a proposal for a space mission, and will be spending 100 nights in Chile this summer observing Barnard's Star, the next nearby star five light years away. He smiles when he tells me about these plans. "You never know what you are going to find, that is the exciting part," he says.

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