The Universe Needs You: To Help in the Hunt for Planet 9

How one citizen science endeavor is using the Internet to democratize the search for distant worlds

Backyard Worlds is using the power of citizen scientists to search for the elusive Planet 9. (Mopic / Alamy )

In 1930, astronomer Clyde Tombaugh first identified Pluto. Tombaugh made his discovery using a device called a blink comparator, which relies on a simple yet elegant technique: look at two pictures of a star field and compare them. If one object moves, it’s a planet or asteroid. About two years ago, Jackie Faherty, a staff scientist at the American Museum of Natural History, decided to update Tombaugh’s technique for the digital age.

Faherty's team built a web site that would allow amateurs to use real astronomical data to find these objects that might ordinarily get missed. The idea, she says, was to use data from space-based telescopes and the Internet to get non-scientists involved in hunting for new objects at the edge of the solar system and near-stars called brown dwarfs that pepper the galactic neighborhood within 100 light years. 

In February, Backyard Worlds: Planet 9 web site blinked online.

Backyard Worlds already boasts a real scientific discovery: a new brown dwarf (a celestial body whose mass is between a large planet and small star) whose discovery was outlined in May in Astrophysical Journal Letters with four citizen scientists listed as co-authors. Another paper is in the works, as the discoveries made through the site are confirmed.

At first glance, Faherty’s project sounds like a win for amateur science. But Faherty bristles at that term. “I wouldn’t call them amateurs. They were curious citizens who would never have thought about astronomy before,” Faherty says, adding that her project is about democratizing science and world-hunting. “The ability to blink and detect motion has nothing to do with getting a PhD.” 

Looking In the Infrared

The data for Backyard Worlds comes from NASA’s Wide-field Infrared Survey Mission (WISE). Launched in 2009, the orbiting telescope peers into space in infrared wavelengths, allowing it to find very dim stars, brown dwarfs or other bodies that don’t shine brightly by their own light as true stars do. There are some 747 million objects in WISE’s catalog, collected over several years of surveys. 

Besides the evidence from gravitational influence on other planets, this is probably how astronomers will eventually track down the elusive Planet 9—if in fact it does exist. 

Marc Kuchner, an astrophysicist at NASA’s Goddard Space Flight Center and the principal investigator for Backyard Worlds, said computers are good at picking up objects when there’s only one in the frame—but humans are much better at finding one in a crowded field. Computers can be led astray by ‘noise’ in the image, from the fact that WISE itself isn’t at a temperature of absolute zero, stray cosmic rays and the diffraction of light.

Enter: Backyard Worlds. At the web site, one can see a “flip book” of four images, shown in rapid succession. If you see something moving, you can tag it with a marking tool, ask if anyone has seen it before in an online forum, and check it against known objects. That’s how Bob Fletcher, a science teacher in Hobart, Tasmania, initially located the brown dwarf in the Astrophysical Journal Letters paper.

"If you had asked the 10-year-old me what I wanted to do when I grew up, I would have said it was to help make a scientific discovery," he says now via email. He continues: "The Backyard Worlds project attracted me early on, since it involved an engaging subject and the possibility of new discoveries. I distinctly remember seeing the object which would become the brown dwarf discovery since it clearly stood out as a stationary flashing object." Later, he says, Kuchner emailed him.

Jackie Faherty, a staff scientist at the American Museum of Natural History and the brains behind Backyard World. (Courtesy Jackie Faherty)

Backyard Worlds had its origins about three years ago, says Kuchner. As he recalls it: “One day Jackie comes up to and says, ‘So you’re looking through WISE data, why not look for objects that are moving, because they could be brown dwarfs.’ And I said, yes we should do that, and forgot about it for a year or two.”

In 2016, the excitement surrounding the possible discovery of Planet 9 rekindled his interest in Faherty’s proposal. That was when he realized that seeking moving objects could also track down Planet 9 as well as brown dwarfs. “But it wouldn’t have happened without Jackie’s clever idea,” he says.

Scanning for distant worlds isn’t mindless; it requires a certain amount of pattern-recognition ability and patience. Not every dot that moves is a world. The involvement of tens of thousands of users, though, resulted in a paper in only a few months—pretty fast for this kind of painstaking work. Backyard Worlds is operated under the aegis of the Zooniverse, a set of about 100 citizen science projects. Kuchner said the Astrophysical Journal Letters paper was the fastest any of them has ever produced published work.

Unlikely Road

For Faherty, Backyards Worlds is more than a fun astronomy project. It’s also about reaching people who wouldn't ordinarily connect with science—a goal that’s close to home, given her own unlikely road to being a scientist. “I constantly think of having access to education, to science,” Faherty says.

Faherty grew up in northern New Jersey—Paterson, Glen Rock and Ridgewood—until she was about 11 years old and the family moved to upstate New York. Paterson was and is very much a working class town, she says. They lived in a house that was shared with extended family. “There was this tiny room with all of our cousins,” she recalls. “We lived there because we had to.”

It was doubly difficult pursuing higher education in science as a woman, because there were few role models. Her mother got an associate's degree, and nobody on that side of the family went to college. Being from a small farming town in Puerto Rico, the usual path was to get married young.

“Especially for young Latina girls, it’s very hard to look through everything that she sees and make the decision she’s going to do something like what I did,” she says now.

That’s why, when she went to college, her initial goal was to be a stockbroker. “I didn’t want to be a scientist,” she said. “I really just wanted to make money. I was good at math but not encouraged to do science.”

Then Faherty saw the sci-fi film Contact, in which a female astronomer (played by Jodie Foster) discovers a signal from an alien civilization, and uses the instructions therein to build an interstellar transport. Something clicked. “It was the first time, maybe the only time there was a woman in the lead in a realistic scientific endeavor,” she says now. “I just didn’t realize it was a possibility before.”

Faherty threw herself into the sciences. Yet rather than encouragement, she was told she didn’t have the background for doing science. “I walked into the chair of the physics department’s office and said I was switching majors. He was not for it.” He told her she was too far behind, and initially she struggled with the material. "I was told I couldn't cut it and I should get out. I didn't listen."

She plunged into the introductory courses and went to tutors to help her with the physics anyways. By the time she graduated from the University of Notre Dame with her bachelors of science in physics, she had exceeded even her own expectations: she won the Outstanding Undergraduate Research Award for undergraduate research. In 2010, she got her PhD from Stony Brook University. 

Afterwards, Faherty continued to follow her fascination in the in-between nature of brown dwarfs, which could be classified as planets if they were orbiting another star. She co-founded the Brown Dwarf NYC research group with Emily Rice, a professor of engineering science and physics at of the College of Staten Island and Kelle Cruz, a professor of astronomy at Hunter College. 

Faherty felt that the initial cool reception from the physics department chair might have had to do with her being a woman, though she says it was never clear. Physics and astronomy are both notoriously male-dominated fields. The National Science Foundation notes that between 1973 and 2012 some 25,668 physics PhDs went to men and 22,172 of those men were white. Only 3,291 PhDs went to women of any race; Hispanic women made up only 106 of those.

The NSF statistics from 2014 are little better. In the physical sciences of the 2,823 doctorates awarded 1,917 were awarded to men, 906 were awarded to women and there were only 45 Hispanic or Latino women in that group. Even the Backyard Worlds team reflects this: Faherty is the only woman on the team.

It’s something her colleagues are conscious of as well. “The science community hasn’t been fair to women or minorities,” Kuchner says, asking: “How many black astronomers are there?” (An American Institute of Physics study from 2014 notes that approximately 1 percent of astronomy faculty are black, and 2 percent are Hispanic.) “This lets us do science with people who might never otherwise get the chance.”

And yet that is a big reason why Faherty embarked on Backyard Worlds in the first place. “Backyard Worlds certainly fits in to my desire to reach any community, especially those that are not as well represented in the sciences," she says. "All you need is access to a computer, the Internet and the desire to excel in astronomy.”

About Jesse Emspak

Jesse Emspak is a freelance science writer based in New York City. His work has appeared in Scientific American, The Economist, New Scientist,, The Christian Science Monitor and Astronomy Magazine.

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