In the wake of its inaugural full calendar year of operations, astronomers are leveraging the capabilities of the James Webb Space Telescope (JWST) to explore the potential for life on a myriad of recently discovered planets. Unveiling the diverse landscapes of these remote worlds, the JWST is proving to be a groundbreaking tool in expanding our understanding of celestial bodies within our galaxy.
Wasp-107b, situated 1,300 light years away, boasts a surreal environment where quartz crystals hover above a scorching atmosphere composed of vaporized sand grains. GJ1214, nicknamed the “sauna planet,” with a mass eight times that of Earth, orbits its parent star in close proximity, enveloped in a thick, steam-laden atmosphere. Meanwhile, the Orion Nebula hosts Jupiter-sized planets freely drifting in space, detached from any discernible parent star, posing a puzzling conundrum for astronomers.
Launched on Christmas Day in 2021, the JWST, with its $10 billion budget, consists of a 6.5-meter gold-plated mirror, a tennis court-sized sunshield, and sophisticated instruments cooled to near absolute zero. This unique configuration enables the telescope to observe the cosmos in infrared radiation, unraveling the mysteries of the universe’s infancy and capturing images of stars emerging from dust clouds.
Beyond its intended purposes, the JWST is proving invaluable for the study of extrasolar planets, also known as exoplanets. Historically, the detection of planets beyond our solar system was challenging due to their diminished size and brightness compared to the radiant stars they orbited. However, advancements in highly sensitive cameras, coupled with the JWST’s infrared capabilities, have led to the identification of over 5,500 exoplanets, with several hundred in proximity to Earth.
Astronomers are now directing their attention to these nearby exoplanets, including Wasp-107b and the enigmatic Orion Nebula rogue planets, scrutinizing their atmospheres and mapping their distinctive features. Professor Jayne Birkby of the University of Oxford highlights the fortuitous position scientists now find themselves in, able to study these distant worlds in intricate detail—a stark contrast to just three decades ago when the existence of exoplanets was uncertain.
The JWST’s recent focus on Trappist-1, a red dwarf star with seven small rocky worlds, is particularly noteworthy. Positioned 40 light years from Earth, three of its planets reside in the habitable zone, offering conditions suitable for liquid water—a key ingredient for the potential flourishing of life. Initial analyses, courtesy of the JWST, reveal that two of these innermost planets possess either no atmosphere or an extremely thin one. Astronomers, including Dr. Jo Barstow of the Open University, express optimism about the Trappist-1 system’s potential to harbor life, emphasizing the ongoing importance of the JWST in unlocking the secrets of our cosmic neighbors.
One particular challenge impacting the investigation of stars like Trappist-1 revolves around the peculiar nature of red dwarfs. While this might not seem like a critical issue, it holds significant implications, as explained by Barstow. Unlike our sun, which has relatively few sunspots associated with intense solar activity, Trappist-1 exhibits dozens of constantly changing spots. This characteristic poses a considerable obstacle in distinguishing between these spots and features of a planet’s atmosphere, making it challenging to unveil the secrets of the Trappist-1 system.
Astronomers utilizing the James Webb Space Telescope (JWST) to explore potential extraterrestrial life focus on identifying a set of biological markers known as the Big Four: oxygen, carbon dioxide, water, and methane. The presence of these elements in an exoplanet’s atmosphere would strongly indicate the existence of some form of life.
Birkby notes, “The exact proportions would vary. Earth’s atmosphere is currently 21% oxygen, but this composition would have been vastly different 2.5 billion years ago, during the time when there was minimal oxygen. Life still existed on Earth at that point, predating the great oxidation event initiated by cyanobacteria producing oxygen through photosynthesis.”
The implications of a world with an atmosphere containing all of the Big Four remain uncertain, and Birkby expresses excitement, saying, “In present-day Earth-like amounts, it would be hard not to get excited.”
Despite the optimism, some scientists exercise caution. Barstow points out, “Even with a perfect profile of gases and water vapor in an exoplanet’s atmosphere, the evidence remains indirect. Claiming definitively that life exists based on these measurements is challenging. Even with 99% certainty, there would still be lingering doubts about the possibility of non-biological phenomena causing the observed effects.”
The James Webb Space Telescope’s future promises both intrigue and longevity. Launched flawlessly on an Ariane 5 rocket from the European Space Agency’s launchpad in French Guiana, the telescope used minimal fuel to position itself precisely, potentially extending its expected 10-year lifespan. However, as Professor Stephen Wilkins notes, the telescope’s performance will degrade over time due to meteorite impacts and cosmic rays. Despite this, astronomers anticipate a wealth of scientific discoveries, especially regarding exoplanets, with Wilkins emphasizing the excitement surrounding the telescope’s ability to unveil the chemistry of exoplanetary atmospheres and reveal previously unknown and unusual worlds.