Yesterday in Washington, D.C. there was a NASA panel about water and its connection with the possibility of finding extraterrestrial life. Some scientists summarized the findings of recent decades obout the presence of water in space and exoplanets. According to Ellen Stofan, chief scientist at NASA, in the course of our life we may finally have an answer whether we are alone in the solar system and beyond.
Ellen Stofan’s statement is motivated by the experience accumulated over the years and water is at the center of everything. Life on Earth is strongly influenced by water and is believed to have been born in water so that’s where the search for extraterrestrial life starts. We are strongly influenced by this because we don’t know other forms of life.
The studies of Titan, the largest moon of Saturn, led many scientists to theorize the possibility that life forms of life may exist that are based on a biochemistry very different from that of Earth. This is extremely interesting but until the possibility of the existence of life on Titan or other places where there’s no liquid water is proved or disproved the efforts of scientists will focus especially on places where there is water.
Hydrogen and oxygen are very common elements in the universe so water is also a substance that can be found in abundance. Astronomers detected the presence of water even in interstellar clouds. However, the most in-depth studies concern water sources existing in the solar system.
For a long time, scientists focused on what is called the Sun’s habitable zone, that in which a planet can hold liquid water. Mars is inside it but because of the absence of a magnetic field to protect it from the solar wind, most of its atmosphere got dispersed in space.
There’s water on Mars and in the first phase of its history it was habitable. Many spacecraft and some rovers studied it and are still studying it to see if the red planet has ever hosted life forms and its evolution into a desert almost certainly dead.
In recent years, the research has expanded. The existence of underground oceans on Europa, one of Jupiter’s moons, and Enceladus, one of Saturn’s moons, made us realize that life forms could exist even in places that in theory are too far away from their star. From this point of view, the latest interesting discovery concerns clues that suggest that Ganymede also has an underground ocean.
All this research helps us understand the possible conditions on planets in other solar systems but we’re just at the beginning of this type of study. The first exoplanet was discovered only 20 years ago and, although now a few thousands of them were identified, They’re a very small part of the oens that exist in the Milky Way only.
This sample sthat is still limited of exoplanets suggests that the most common ones are of the types known as super-Earth and mini-Neptune. Many planets may be completely covered by oceans. The research is in the process of development and the experience accumulated over the past decades is allowing to build new instruments and to interpret in a more and more complete way the data collected.
NASA is planning a mission called TESS (Transiting Exoplanet Survey Satellite), a new exoplanet hunter. ESA is developing the Plato (Planetary Transits and Oscillations of stars) mission for the same purpose. The James Webb Space Telescope will help in the study of exoplanets as well.
Before the discovery of the first exoplanet, many scientists were pessimistic about the possibility of going beyond the theory in the study of possible alien life forms. The discoveries of the past 20 years turned this attitude upside down and today the study of exoplanets is considered very interesting, especially among the younger generation. The discovery of alien life forms, in the solar system or beyond, could really take place in the near future.