To Boldly Build: Caltech's Lego-Loving Exoplanet Hunter

Lego space shuttle and Lego Hubble telescope

Photo: Jessie Christiansen

Jessie Christiansen gave a lecture of her dreams this summer, but it was not delivered to an audience of her astronomer or exoplanet-hunter peers. This talk was for the Lego lovers.

On August 17, Christiansen, a Caltech research scientist with IPAC, spoke to the Lego Creative Play Lab, a kind of think tank in which the Lego company hears about innovative ideas that could inspire the Lego sets of the future. She explained the search for new worlds and outlined the kinds of theoretical instruments that could aid in finding exciting exoplanets, and perhaps signs of life, out there in the cosmos. It was a dream come true for the longtime Lego enthusiast.

“I love Lego,” Christiansen said. “You'd probably be hard pressed to find someone with a STEM career who wasn't excited about Lego when they were a kid. I didn't have a lot of my own, but my cousins had some. Whenever I would visit their house, I would be in the Lego drawer making Lego. It was just, ‘Hi, people. Now, Lego.’"

Logo kit - Women of NASA

Photo: Jessie Christiansen

Lego came back into Christiansen’s life when she moved to Pasadena. She had relocated a lot as an early-career academic, but once she settled at Caltech, she had the stability to own more sets—and, once she had kids, a built-in excuse to buy more blocks.

Jessie Christiansen holding Logo blocks

Photo: Jessie Christiansen

It wasn’t long before she became known as a Lego-loving astronomer on Twitter. Several years ago, Christiansen’s high school back in Australia, where she had lived until 2008, hosted a fundraiser, and she decided to donate Lego’s Women in Science kit autographed by a group of her female colleagues at Caltech and JPL, which the Institute manages for NASA. More recently, she tweeted a miniature Lego James Webb Space Telescope she built at a conference, which now sits on her desk (with a mini-figurine of herself riding on it) and the just-opened space shuttle kit she went on to build with her children this past Labor Day weekend.

Christiansen’s social media love for the toy brand caught the attention of Remo Collet, astronomer-turned-senior-play AI engineer at Lego, who invited her to speak to the group. She accepted and was in London in July ready to give the talk in person at the Creative Play Lab when she came down with COVID-19, which delayed the event and forced her to give the talk after she got back to California—but on London time.

During that talk, she walked her audience through the history of exoplanets, from their discovery in the 1990s up through today’s best telescopes and exotic proposals for the future of planet hunting. One example: a wild theoretical idea to use the sun as a gravitational lens. If you placed a telescope a thousand times farther from the earth than the sun is, and in exactly the right spot, she said, you could use the sun’s gravity to focus a huge amount of light onto the single spot where the telescope is. “You could mimic a very, very large telescope that way. That's just a pen-and-paper idea right now, but that's a super cool idea.”

It’s just the kind of idea to inspire a new Lego set—the kind that might spark the imagination of the next professional astronomer.

“We're at this really unique place in human history where people alive right now might find proof of life on other planets,” Christiansen says. “We know that exoplanets exist. We know that there are rocky planets in the habitable zones of their stars, and we are designing and building the next generation of instruments, telescopes, and spacecraft to be able to peer into the atmospheres of these planets and find signatures of life.

“Even though humans have always been thinking—‘Are we alone? What else is out there?’—right now is the time when we might know the answer, and that's wild.”