The main goal of modern astronomy and planetary science is to discover the components of life spread throughout the universe. Two scientists studying exoplanets and astrobiology believe that thanks to next-generation telescopes like the James Webb Telescope, most researchers will soon be able to measure the chemical makeup of the atmospheres of planets around other stars.
The two scientists’ best hopes are to find that there is a chemical trace of life on one or more of these planets. Two researchers, who think that there may be life in the Solar System, as in previous discoveries on Mars or Jupiter, say that a telescope should be sent to obtain physical samples, since it is difficult to look for signs of life in space or on the sun.
The James Webb Space Telescope is the only telescope to discover changes in light in space.
Astrobiologists will study starlight interacting with a planet’s surface or atmosphere to detect life on a distant planet. If the atmosphere or surface has been transformed by life, the light may carry a cue called a “biosignature.” Detecting these subtle changes in light from a potentially habitable exoplanet would require an incredibly powerful telescope. For now, the only telescope with such success has been the new James Webb Space Telescope.
Beginning science operations in July 2022, James Webb read the spectrum of the gas giant exoplanet WASP-96b. The spectrum showed the presence of water and clouds, but a planet as large and hot as WASP-96b is also considered unlikely to host life. But these early data show that James Webb was able to detect weak chemical signatures in light from exoplanets.
Webb will explore planets closer to Earth in the coming months
In the coming months, Webb prepares to turn its mirrors to TRAPPIST-1e, a potentially habitable Earth-sized planet just 39 light-years from Earth. The telescope can look for biosignatures by studying planets as they pass in front of their host stars and by capturing starlight filtering through the planet’s atmosphere. But because it’s not designed to search for life, the telescope can only examine a few of the closest potentially habitable planets. It can also only detect changes in the levels of carbon dioxide, methane and water vapor in the atmosphere. Only a fraction of what we have written indicates the existence of life, and Webb fails to detect the presence of oxygen, the strongest sign for life.
The researchers noted that there are three massive, ground-based Giant Magellen Telescopes, Thirty Meter Telescopes and European Extremely Large Telescopes currently under construction that can search for biosignatures, each much more powerful than existing telescopes on Earth. These telescopes can easily probe the atmospheres of the closest planets for oxygen, although Earth’s atmosphere distorts the starlight.
Even if astrobiologists use the most powerful telescopes in the coming decades, they will only be able to detect powerful biosignatures produced by worlds that have been completely transformed by life. To avoid false results, astronomers and astrobiologists will need to study a planet of interest well enough to understand whether its geological or atmospheric processes can mimic a biosignature. Still, next-generation exoplanet studies have the potential to break the bar for the extraordinary evidence needed to prove the existence of life in space. Early findings from the James Webb Space Telescope give us an idea of the exciting progress that will soon take place.
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