New probes to study nearby worlds, advanced telescopes to peer at far away planets, and expanding ideas about the signs of life are fueling a renaissance in the search for life beyond Earth.
Why it matters: It’s an age-old question — is life as we know it on Earth unique, or is the universe actually teeming with life?
New probes to study nearby worlds, advanced telescopes to peer at far away planets, and expanding ideas about the signs of life are fueling a renaissance in the search for life beyond Earth.
Why it matters: It’s an age-old question — is life as we know it on Earth unique, or is the universe actually teeming with life?
The big picture: The boom in the search for life isn’t just about more funding and better telescopes, says Andrew Siemion of Breakthrough Listen, a project combing space for radio signatures of life.
- “We’re also seeing a Copernican revolution take place within astronomy, where the ubiquity of extrasolar planets is being viscerally felt and understood. That has really shaped the question of whether we are alone and the search for life.”
- More than 4,000 exoplanets have been discovered, almost entirely in the last three decades, but as far as scientists know, Earth’s life still remains unique.
What’s happening: Upcoming missions will search for signs of life — and conditions for it — on worlds near and far from Earth.
- NASA is slated to send two new missions to Venus in hopes of better understanding how a planet’s geology is tied to its ability to harbor life and determining whether phosphine — a possible signature of life — is present in Venus’ cloudy atmosphere.
- Japan plans to send a robot to Mars’ moon Phobos in 2024 to collect and return samples from the satellite, which some scientists think may actually be the best place to search for signs of life on the Red Planet. Other missions to gather samples from Mars itself are also underway.
- “We’re not in recon mode anymore, at least in the inner solar system,” says Bethany Ehlmann, a professor of planetary science at Caltech.
Jupiter’s moon Europa will be studied for signs of life in a NASA mission planned for the next decade. Researchers are pitching a similar study of Saturn’s small, icy satellite Enceladus, a potentially habitable harbor in our solar system.
- “Although these worlds don’t exist in the classical habitable zone, conditions could be favorable for life in the vast oceans that exist beneath their ice shells,” says Lynnae Quick, a planetary scientist at NASA who studies ocean worlds and is a member of the science team for the Europa Clipper mission.
Beyond the boundaries of our solar system, scientists are continuing the search for signs of life that aren’t molecules from microbes but radio signals that would indicate other technologically advanced life is out there.
- But today’s sophisticated technology may still not be sensitive enough to detect signals from other worlds so new radio telescopes are being developed, like the Next Generation Very Large Array and the Square Kilometer Array observatory, with larger collecting areas — and therefore more sensitivity — than today’s radio telescopes.
- “It will be the first time [we can be] truly sensitive to an Earth-like civilization in any snapshot observation,” Siemion says.
What to watch: As modeling of planetary atmospheres improves and scientists’ understanding of the diversity of worlds widens, they’re starting to look for even more fundamental signs of life.
- There appear to be patterns in the chemical reactions of living systems that differ from not-living systems, says Tessa Fisher, a graduate student at Arizona State University who is studying these reactions.
- And more complex molecules typically take more steps to create, she says. The molecules created in each reaction could be measured with an instrument on a space probe.
- This work is “demonstrating a shift toward looking for a smoking gun for evidence of life — oxygen or amino acids — to thinking about life from a systems level point of view and looking at how life interacts with its environment.”
Far out: “By 2051, I expect there will be some astronomy being done from the Moon,” Siemion says.
- There, astronomers don’t have to contend with Earth’s atmosphere and interference from radio signals. Siemion and some other researchers are proposing a “lunar astronomy village” of telescopes that share infrastructure.
- “It is more sci-fi but with the pace of things it may not be so far-fetched,” he says.