Stars in his eyes: An Amherst man scrutinizes space to help scientists discover new planets
Ernie Dalkas looks at a website called Planet Hunters to try to discover planets Wednesday at his home in Amherst.
JERREY ROBERTS Purchase photo reprints »
Open star cluster Purchase photo reprints »
Ernie Dalkas of Amherst uses a website called Planet Hunters to try to discover planets.
JERREY ROBERTS Purchase photo reprints »
Planet Hunters website
JERREY ROBERTS Purchase photo reprints »
AMHERST — Ernest “Ernie” Dalkas, a retired construction engineer, spends his days searching for new planets, preferably ones where living, breathing creatures might be found.
He’s not peering at the sky through a high-powered telescope, though. He’s sitting in an easy chair in the living room of his Amherst home, scrolling through laptop screens filled with patterns of white dots.
Usually, the television is on.
“It’s something good to do while listening to golf,” Dalkas, 64, said in an interview last week. “It’s fascinating and fun. It’s mindless work that helps pass the time, but it’s also productive.”
Dalkas is a volunteer for Planet Hunters, at www.planethunters.org. It’s not some kooky collection of science fiction lovers. It’s a serious group of 200,000 volunteers sanctioned by NASA and Oxford University. A Yale professor is among its founders.
And he is one of 180 amateur scientists who have helped to identify the most recent potential life-bearing planet candidate, for which he received credit in a January piece published in Astrophysical Journal.
Planet Hunters disseminates data from the Kepler spacecraft, a mission launched by NASA in 2009, in which a telescope sent into outer space points at 160,000 distant stars and collects their brightness data every 30 minutes. The data are then released in what are called light curves, representing 35 days of data. The use for these data, represented by the specks of white against the black screen, is locating habitable planets.
If the light curves indicate a planet is passing by the star, there will be one or more dips in the light curve. And if these planets are determined to be in a zone not too distant from the host star, there is a chance they could support life.
So far, the Kepler mission has confirmed 105 planets and has 2,740 planet candidates. The scientific team uses an algorithm to detect the movement of planets around the stars being monitored, but some planets can slip through these programs. Thus the need for actual human observation of the light curves data.
The article in Astrophysical Journal notes that through Planet Hunters “a few unique systems were identified that had been overlooked by the Kepler automatic detection and validation pipeline.”
The planet Dalkas helped find is called 10096941.
He said its radius is five times larger than Earth’s. The planet itself might not be able to support life, he said, especially if it is a gas giant more akin to Jupiter, but would likely have moons orbiting it that may have their own atmospheres and rivers of water.
That’s for the NASA scientists to determine.
“I think it’s very exciting that an average citizen without an advanced degree in science can still make a discovery that helps advance our understanding of the universe,” Dalkas said.
Debra Fischer, a Yale professor who helped start Planet Hunters in fall 2010, said that having observers scrutinize the data helps the trained researchers.
The idea of putting the data out in such a public way, she said, came from a postdoctoral fellow who was interested in ways of involving the public and seeing whether they could support the scientific teams. This dovetailed with efforts by Chris Lintott, a professor at Oxford University, to involve non-scientists in real science projects that had already been taking place online.
Fischer said there is an appetite for this kind of research among the public, as the discovery of planets outside the solar system, known as exoplanets, is fascinating to many people.
“Everyone loves exoplanets,” Fischer said.
The actual work involved isn’t terribly labor-intensive.
Most days when he has some spare time, Dalkas settles into his living room, logs into his Planet Hunters account and selects the “classify” button. A white bubble pops up next to the light curves, indicated by distinct dot patterns, some that are straight and others that undulate, prompting a series of questions in which Dalkas classifies the seemingly random light curves he is assigned.
Dalkas identifies each one’s traits as quiet or variable, then, based on its pattern, further determines whether he thinks the light curves represent a regular star, a pulsating star or an irregular star.
Then he moves on to the search for the so-called transits of planets. If the light curves exhibit a transit, usually evident in the light wave making a sharp move downward on the screen as the star’s brightness dims, Dalkas points the cursor at the spot and marks it. Once he has completed this process, which takes between 5 and 10 seconds, he moves on to another light curve.
“The idea is that people are good at spotting patterns,” Dalkas said. “It’s proven to be very helpful. We’ve discovered quite a few planet candidates.”
Dalkas added that he can go days without a planet candidate and then suddenly mark several light curves with possible planets. He has evaluated and classified close to 140,000 of these light curves, spending an estimated 400 hours doing it over the past 18 months. The planet he helped to identify is the only one verified as likely to be a planet in a habitable zone, but he has marked an additional 63 candidates that have passed an initial vetting process by the scientists, he said.
Fischer said there are a number of tests to figure out whether the transit candidates are really planets, including taking observations from the W.M. Keck Observatory in Hawaii and determining whether people might be mistakenly marking what are known as stellar binaries, or two-star solar systems, instead of planets.
“There’s a whole checklist we go down,” Fischer said.
Dalkas said that neither his wife, Ellen, nor his children, Jared, 17 and Lacey, 12, share his interest in space, though it was his daughter who indirectly got him involved in the project. After she pleaded for a dog, Dalkas said, he got one for the family, which he now ends up taking on daily walks. During these walks he often listens to podcasts of “Search for Extraterrestrial Life’s Big Picture Science,” a program where he first heard about Planet Hunters.
Dalkas, a disabled Vietnam War veteran, said he has always been interested in space and the origins of life, enjoying listening to “Star Talk,” a radio show hosted by astrophysicist Neil deGrasse Tyson, director of the Hayden Planetarium at the American Museum of Natural History. As a volunteer, he feels he is helping in the quest to find life beyond Earth.
The Kepler data released so far include 2.4 million distinct light curves, so Dalkas has seen fewer than 6 percent of those available to analyze. But volunteers have combined to classify 17.07 million light curves, meaning each one, on average, has been examined more than seven times, adding to the precision.
Fischer said she estimates the 17.07 million views of light curves by Planet Hunters volunteers is the equivalent of 100 years it would take just one person to evaluate the data. Their work has already doubled the number of exoplanets found by the Kepler team, she said.
“This is not just a public outreach program, this can bring a large crowd of people together,” Fischer said. “Their eyes and brains are looking at data and making a difference.”
Fischer said Planet Hunters is easy and understandable enough for anyone to use. Volunteers include everyone from schoolchildren to retired engineers, not just those who would normally be interested in science, she said.
“There’s not a pigeonhole,” Fischer said.
Dalkas said he sees it as a way for ordinary citizens to participate and make discoveries.
“It gives people like me, with just a few minutes of training, the opportunity to start making these discoveries,” he said.