American Physical Society Sites|APS|Journals|Physics Magazine
- American Physical Society Sites
- Meetings & Events
- Policy & Advocacy
- Careers In Physics
- About APS
- Become a Member
Searches for life on other planets get the Congressional spotlight
October 1, 2015 | Emily Conover
Photo: NASA Ames/JPL-Caltech/T. Pyle
An artist's depiction of the planet Kepler-452b, the first near-Earth-size world to be found in the habitable zone of a star similar to our sun.
In an uncharacteristically harmonious and enthusiastic meeting of the House Committee on Science, Space, and Technology on Tuesday, September 29, curious representatives peppered four scientists with questions about the search for life on other planets. Fortuitously, the event fell the day after NASA unveiled strong evidence for liquid water on Mars that grabbed headlines and captured the public imagination — apparently including members of the Science Committee: Chairman Lamar Smith said he was "absolutely astounded."
One representative resorted to poetry to express his appreciation for the search for life on other planets — Ed Perlmutter (D-CO) recited a Tennyson quote written on the wall of the meeting room — "For I dipped into the future, far as human eyes could see, saw the vision of the world, and all the wonder that would be.” The research, he added, "gives me goosebumps."
Astrobiology — the study of life in our solar system and beyond — unites a variety of fields, including astronomy, physics, biology, and geology. At the hearing, the scientists discussed the possibilities for microbial life on the four solar system bodies considered possible hosts — Mars, Europa, Titan, and Enceladus — as well as current and upcoming exoplanet research, and efforts in the search for extraterrestrial intelligence (SETI).
In her testimony, NASA Chief Scientist Ellen Stofan focused on the search for life — either current or fossilized — on Mars. She highlighted the astrobiology capabilities of the planned Mars 2020 rover, but argued that NASA's plan for a crewed mission to Mars is also essential to finding life, if it's there. "I believe it will take human explorers — geologists and astrobiologists — who can move quickly and make intuitive decisions on their feet," she said.
But how might one detect the fingerprints life may have left on the solar system's four likely suspects? Jonathan Lunine of Cornell University explained, "The evidence will not be entire living organisms. Much more likely is that we will detect signatures that indicate that life is at work or was at work in these environments," Lunine said. "Biology is built from a very limited, selected set of molecules. And so if we can recognize patterns in the makeup of organic molecules and their isotopes, we then have strong evidence of biology at work."
Jacob Bean of the University of Chicago made the case for zeroing in on exoplanets in the search for life. Telescopes are currently scouring the skies for Earth-sized planets in the habitable zones of their stars, and by using spectroscopy to identify components of exoplanet atmospheres, scientists may eventually be able to detect "biosignature gases," like molecular oxygen, that could point to a foreign planet crawling with creatures. Bean highlighted the importance of the Kepler telescope and the upcoming James Webb Space Telescope and Transiting Exoplanet Survey Satellite for these efforts. But in order to study the atmospheres of the most enticing prospects — Earth-like planets around Sun-like stars — an expanded program in exoplanet exploration, including a flagship telescope with next-generation optics, will be needed, he said.
If other intelligent life exists, scientists could detect its technology using radio telescopes like the Arecibo Observatory and the Green Bank Telescope. "These facilities are among the world's best at searching for the faint whispers of distant technologies," said Andrew Siemion, director of the SETI Research Center at the University of California, Berkeley. He cited the Breakthrough Listen initiative — a $100 Million, 10-year effort funded by Russian billionaire Yuri Milner's Breakthrough Prize Foundation — as an exciting prospect in the next decade.
The search for life on other planets, lawmakers noted, can inspire young people to pursue science, and they stressed the importance of outreach. "While it's exciting to search for intelligent life elsewhere in the universe, I hope we don't neglect nurturing the intelligent life we have right here in our country," said Eddie Bernice Johnson (D-TX).
Stofan was optimistic about the probability of discovering life on another planet; instruments under development could allow scientists to discover some form of life within as little as 10 to 20 years, she said. But Bean was less sanguine, calling the possibility of finding biosignatures from exoplanets in the next decade "unlikely," an answer that seemed to disappoint Chairman Smith.
The experts agreed that astrobiology research should be prioritized, and emphasized the importance of uninterrupted funding if progress is to be made. "I think that life is the most interesting property of the universe," said Siemion. "If we don't understand that, then I think we don't understand perhaps one of the most fundamental properties of the universe that we live in."