E.T. has not been found, but Cornell astronomers may be taking a step in the right direction. Using data collected from the NASA Kepler Mission, which examined a portion of the Milky Way galaxy, a team of Cornell researchers recently identified three Earth-like planets, all of which, they said, could host life.
The findings were published online April 23 in Astrophysical Journal Letters.
According to Phillip Muirhead Ph.D. ’11, the lead author of the study and a current researcher at California Institute of Technology, the astronomers used the Cornell-built Triple Spectrograph — a state-of-the-art instrument that allows astronomers to efficiently measure the properties of stars — to identify “planet candidates,” or bodies that resemble the Earth in size, mass and temperature.
“We found that these particular [three] planet candidates reside at distances from their star where they receive an amount of light similar to the Earth,” he said. “Therefore, we say that these planets reside in their star’s ‘habitable zones.’”
Prof. James Lloyd, astronomy, another co-author of the paper, said that access to light indicates that the planets are strong candidates for hosting life.
“There are good reasons to believe that life is common in the sense that it probably occurs many times throughout the Universe, but the Universe is a big place, so we need to know where to look,” he said. “These three planets make the top of the list of the best places we know to look.”
Bárbara Rojas-Ayala Ph.D. ’12 another of the study’s co-authors, who is now a researcher at the American Museum of Natural History, said that liquid water is essential for life on Earth — but, with the technology currently available to scientists, it is impossible to distinguish whether these planets contain water.
“With the current technology, it is not possible for us to observe the atmospheres and surfaces of these planets. Therefore, we cannot know for sure if they even have conditions favorable for life as we know it,” Rojas-Ayala said. “Still, these planets should be the preferred targets for future space telescopes to study their atmospheres.”
Lloyd said that the researchers hope their work will inspire other scientists to point their telescopes in the direction of these new planet candidates.
“There are many more planets being found by Kepler on an ongoing basis, and the same kind of characterization to determine their sizes and temperatures is needed,” he said. “We will need to find out in detail whether the planets have atmospheres, [if they] can support life and, ultimately, if they do.”
Muirhead said that astronomers can use space telescopes such as the Hubble Space Telescope to study these plants’ atmospheres.
“If we detect signatures of life, such as oxygen and methane, that would provide evidence for extraterrestrial life in the Universe,” he said.
Lloyd touted the collaborative nature of the project, which brought together the techniques developed by two of his graduate students in their Ph.D. theses.
“[This research is] a great example of how science can be greater than the sum of its parts,” he said, “And how the work of graduate students on some very narrow details makes the difference in a really important problem: knowing which planets are potentially habitable.”