The search for an Earth-like planet is one of the key goals of astronomers. The closer a potential planet for settlement is to us, the better.
Since its discovery the first planet outside our solar system in the 1990s, NASA and astronomers around the world were intensively searching for a second Earth – a planet that could not only support life, but also offer conditions similar to those we experience every day.
A key factor in the search for planets capable of supporting life is the so-called habitable zone. This is the distance from the star at which liquid water could exist on the planet’s surface. Water is considered one of the basic ingredients necessary for the development of life. The planet must also have enough mass and size to maintain an atmosphere that can stabilize temperatures and protect against harmful cosmic radiation. The ideal planet would be rocky, like Earth, because gas giants like Jupiter and Saturn cannot support life as we know it.
In addition, the star around which the planet orbits plays an important role. Stars similar to the Sunclass G, are the best candidates because they emit stable light and heat for billions of years, which provides a chance for life to evolve. Nevertheless, there is increasing interest in the so-called red dwarfs – smaller and cooler stars that make up the majority of our galaxy. While their stellar activity may be more variable, planets in their habitable zones are easier to discover.
How can we find another Earth?
The most important tools in the search for new planets are space telescopes. The Kepler mission, launched in 2009, was a breakthrough in exoplanet research. This telescope observed over 150,000 stars in one selected region of the sky, looking for tiny drops in brightness caused by a planet passing in front of its star. Thanks to Kepler, scientists have discovered thousands of planets, including many potentially rocky objects similar in size to Earth.
Kepler’s successor is TESS (Transiting Exoplanet Survey Satellite)which launched in 2018. TESS differs from Kepler mainly in the scope of its search – instead of focusing on one region, it monitors almost the entire sky, looking for planets around stars relatively close to Earth.
However, a real breakthrough in the study of exoplanet atmospheres comes with the James Webb Telescope (JWST), which began its observations in 2022. JWST, equipped with advanced tools for examining infrared lightallows astronomers to analyze the chemical composition of the atmospheres of distant planets. This makes it possible not only to confirm whether water may exist on a given planet, but also to examine whether there are other substances in the atmosphere that could indicate the presence of life, such as methane or oxygen.
Have we found the second Earth yet?
Scientists have already found at least several planets that would meet the conditions to become a potential “second Earth”. However, the problem is always the same. They are far enough away to be beyond our reach. Even moving at the speed of light, It would take several generations to reach such a planet. One of the most promising discoveries is the planet TOI 700 d. It is located about 100 light-years away from us, in the TOI 700 star system. This planet orbits in the habitable zone of its star, which means that water could exist on its surface. Interestingly, TOI 700 e, the smaller sister of TOI 700 d, is also located in this zone, making the whole system a fascinating target for future research.
Another interesting case is the TRAPPIST-1 system, where as many as seven rocky planets orbiting a red dwarf were discovered. Three of these planets are in the habitable zone and their masses and sizes are comparable to Earth. This system, located just 40 light-years away, is one of the best studied by telescopes, and its planets are ideal targets for JWST.
Graphics: depositphotos
Source: antyweb.pl
