In 2025, we may detect the first signs of life outside our solar system.
This potential is important for success 6.5-meter-diameter James Webb Space Telescope (JWST). Launching in 2021, on an Ariane-5 rocket from Kourou, a coastal town in French Guiana, JWST is our largest space telescope to date. Since it began collecting data, the telescope has allowed astronomers to observe some of the most dim objects in the universe, such as ancient galaxies and black holes.
Perhaps more importantly, in 2022, the telescope also gave us our first glimpse of rocky exoplanets in what astronomers call the habitable zone. This is the region around a star where the temperature is just right for the existence of liquid water – one of the key ingredients of life as we know it – in the planet’s rocky surface. These Earth-sized planets were found orbiting a small red star Trappist-1A star 40 light-years away with one-tenth the mass of the Sun. Red stars are cooler and smaller than our yellow Sun, making it difficult to detect Earth-sized planets orbiting them. Nevertheless, the signal detected from exoplanets is usually weaker than the signal emitted by a more luminous host star. Discovering these planets was a very difficult technological achievement.
The next step – detecting molecules in planetary atmospheres – will be an even more challenging astronomical feat. Every time a planet passes between us and its star—when it transits—the star’s light filters through the planet’s atmosphere and hits molecules in its path, creating the spectral absorption features that We can search. It is very difficult to identify these features. To accomplish this, JWST will need to collect enough data from multiple planetary transitions to suppress the signal from the host star and enhance the molecular properties of the incredibly thin atmospheres of rocky exoplanets (if you squish these planets into an apple). , for example, at that scale their atmosphere would be thinner than a fruit peel). However, with a space telescope as powerful as JWST, 2025 could be the year we finally detect these molecular signatures.
TRAPPIST-1’s detection of water in exoplanets, however, is not our only chance to find life in distant exoplanets. In 2024, for example, JWST also revealed possible signs of carbon dioxide and methane in the atmosphere. K2-18bis a planet located at a distance of 124 light years from Earth. K2-18b, however, is not a rocky, Earth-like planet orbiting its star in the habitable zone. Instead, it is likely to be a giant gas ball with a water ocean similar to Neptune (though smaller in size). This means that if there is life on K2-18b, it could be completely different from life as we know it on Earth.
In 2025, JWST will likely shed more light on these tantalizing discoveries, and hopefully confirm for the first time, if there is life on alien worlds light-years away from our own.
