Which forecast describes the time frame for detecting spectral signatures of life on planets and moons around other stars?

• A. Within a few centuries
• B. Within a couple of decades, we will probably be able to detect the spectral signatures of life on planets and moons around other stars.
• C. Not in the foreseeable future
• D. More than a millennium

Answer: (B)

Detecting life-related spectral signatures on planets around other stars relies on pushing the capabilities of telescopes to high-contrast spectroscopy and direct imaging so we can separate a planet’s faint light from its star’s glare. The best forecast is that within a couple of decades we will probably be able to detect these atmospheric biosignatures, because current and planned observatories—both space-based and ground-based—are being developed with the goal of measuring exoplanet atmospheres and searching for gases like oxygen, ozone, methane, and water vapor in combinations that hint at biology. This near-term timeline reflects the steady progress and investments underway, making it more plausible than centuries or millennia-long horizons, while acknowledging the substantial challenges involved.