Planetary Scientists Hope to Discover What No One Has Found Before

LIFE IN SPACE?

Kepler-186f

ARTISTS’ RENDERINGS/NASA Planetary scientists hope to discover what no one has found before

By Paige Bowers than 20 years ago when scientists at Ames exoplanets Kepler-186f — an Earth-size Research Center in California determined body in the habitable zone of a star that’s IS IMAGINATION SPARKED BY that a high-powered photometer could smaller than the sun — and Kepler-452b, original Star Trek episodes measure the faintest fluctuation of which is in the habitable zone of a star he watched as a boy, John brightness in stars — a dip that signified a similar to the sun, Grunsfeld said. Grunsfeld stared at the night planet had passed in front of the star. After “What it means to me is that there are sky and wondered whether building a photometer accurate enough for other Earth-like planets in the habitable Hplanets orbited the twinkling stars beyond the task, NASA scientists discovered three zone and we haven’t seen them yet,” our solar system. If such planets existed, exoplanets in ground observations that Grunsfeld said. “My guess is that we’ll Grunsfeld mused, would they be inhabited began in 1995. learn about them in the next year or so.” by some sort of life form? In March 2009, NASA launched its Kepler In the meantime, these discoveries “It didn’t seem real,” Grunsfeld said. mission, sending a photometer into space are helping NASA design its next set of “But (space) was the source of our modern to find exoplanets. Five were discovered missions. westerns.” in Kepler’s first 43 days of data, and, since The Transiting Exoplanet Survey Satel- Kepler-452b Now, as associate administrator for then, a total of 1,030 planets have been lite (TESS) and the James Webb Space NASA’s Science Mission Directorate, confirmed through the mission. Telescope (JSWT) will go into orbit in 2017 Grunsfeld has overseen research that has “When we designed and built (the and 2018, respectively. Grunsfeld said the Kepler-186f — the first validated Earth- answered at least one pressing question photometer and Kepler), we didn’t know telescope’s infrared technology could help size planet orbiting a distant star in the from his youth: There are nearly 1,900 if planets were common or rare,” said Paul scientists study the exoplanets in detail like habitable zone — is in the Kepler-186 star exoplanets — or planets orbiting a star Hertz, NASA’s director of astrophysics. never before, allowing them to find signs system, about 500 light-years from Earth. other than the sun — in our region of the “Kepler data shows us that pretty much of life through “biosignature gases” such as Kepler-452b, dubbed “an older, bigger Milky Way galaxy. every star has planets around it, and oxygen, carbon dioxide or sulfur dioxide. cousin to Earth,” takes 385 days to orbit “Now that we know there are planets one-fifth of those stars has a rocky planet NASA also announced this spring the the star Kepler-452, which is 1,400 light- everywhere, the big question is whether — like Earth — in its habitable zone (a range formation of a coalition of experts to look years from Earth. anyone is out there,” Grunsfeld said. of distance from a star where liquid water for life on planets beyond our solar system. “We’re on the cusp of being able to answer might pool on the planet’s surface).” Nexus for Exoplanet System Science that.” Kepler regularly discovers new planets. For NASA, the breakthrough began more Two of its most notable discoveries are the CONTINUED EXOPLANETS An artist’s rendering, courtesy of NASA, shows the relative sizes of some exoplanets discovered by Kepler that are in a habitable zone.

Kepler-22b Discovered in 2011 with a temperature similar to Earth’s.

Kepler-69c A year on Kepler-69c takes about 242 Earth-days to complete. Kepler spacecraft

BALL AEROSPACE; ARTIST’S RENDERING/NASA The centuries-old quest to find Earth-like planets orbiting other stars spurred NASA to launch the Kepler spacecraft on March 7, 2009. At left, scientists lower the photometer onto Kepler in a clean room at Ball Aerospace & Technologies Corp. in Boulder, Colo. At right is an artist’s rendering of Kepler in space. The spacecraft, named after the German Renaissance astronomer Johannes Kepler, was designed to look for planets crossing in front of their host stars. To date, Kepler has found 1,030 confirmed exoplanets.

Kepler-452b Larger than Earth, the gravity on Kepler-452b is also stronger. (NExSS) connects scientists in several key we want to bring these developing powerful disciplines, including earth and planetary people to the table.” telescopes that will be sciences and astrophysics. One of the scientists is “My goal for the able to examine planets “We knew that the science being used to Penelope Boston, director rest of my career in finer detail. figure out some of these questions would of cave and karst studies “Right now, we require a broad community of people,” at the New Mexico is to work on this can’t take pictures of said Shawn Domagal-Goldman, a research Institute of Mining and question of how elephants grazing on the scientist in the Sciences and Exploration Technology. Boston, plains on planets of other Kepler-62f Directorate at NASA’s Goddard Space Flight who crawls down into many planets are stars,” Hertz said. “Our Researchers think Kepler-62f is Center and member of two NExSS teams. hot tropical caves to out there that best technique is to look likely engulfed in water. “We just needed a new network to make search for microbial life, for gases in the atmo- that happen.” believes that if we can could harbor life sphere that wouldn’t The network unites at least 15 teams of find life in dangerous and how many exist if there were no life. scientists and offers research grants. More caves on our own planet, If we were to see those importantly, it gets those teams to share we can probably use have signs of life.” kinds of gases, we could their perspectives in virtual meetings, the same techniques — Shawn Domagal-Goldman, ask ourselves whether workshops and white papers so that to discover life in other research scientist at NASA’s they were caused by life Kepler-186f the overall science becomes stronger, planetary caves. Goddard Space Flight Center or something else.” Research suggests that Kepler- Domagal-Goldman said. Astrobiologist Victoria Hertz is excited about 186f’s terrain is likely to be rocky. “For me personally, my goal for the rest Meadows, a University of the future. “Life appears of my career is to work on this question Washington astronomy to have arisen quickly of how many planets are out there that professor, is building computer models of and robustly on Earth and it seems unlikely could harbor life and how many have signs the stars Kepler is monitoring so she can that it was an accident or one-of-a-kind of life,” Domagal-Goldman said. “To get develop a catalog of planets that could exist event,” Hertz said. “If the same conditions there, you have to ask questions like, what around those stars. we have here on Earth exist on (these are the properties of the star? Are there Other scientists are using computer simu- exoplanets) … it’s time for us to go out and Earth other planets in the system? What is the lations to create models of how planetary find data to see if this hunch is actually No exoplanet comes close to composition of the star and does that influ- systems form so that they can determine correct. It’s exciting that we’re living in matching Earth’s environment. ence the composition of the planet? And how these worlds would have to evolve a time when we can turn our telescopes so on. … It gets so complicated so quickly to sustain life. They are also exploring the and apply our science to that question and with just a simple question. That’s why Earth’s frozen lakes for signs of life and maybe get an answer.”