Given the numerous factors influencing the potential for life on another planet, astronomers often employ a simplified approach. The most crucial element for life, as we understand it, is the availability of liquid water. Therefore, this forms the cornerstone of current habitability searches. Astronomers aim to identify exoplanets that fall within the temperature range conducive to having liquid water on their surface, specifically between 0 and 100 degrees Celsius.
James Webb begins its search for exoplanets by initially focusing on stars. As mentioned earlier, stars are significantly brighter than planets, making them easier to observe. By closely examining a star, one can detect signs indicating when a planet crosses in front of it. This event, known as a transit, causes a slight decrease in the star’s brightness. Typically, the brightness dips by around 1%, but this small change is sufficient for detection.
When astronomers observe a star and notice regular dips in its brightness, they can deduce that a planet is orbiting the star. By observing how frequently these transits occur, astronomers can gather information about the planet’s orbital period.
This detection technique is called the transit method and is one of the primary methods astronomers use to discover exoplanets with various large telescopes. However, James Webb has an additional capability: it can not only observe transits but also analyze the atmosphere of exoplanets.
