Astrophysics follows three approaches to answering this question. We may have another mission soon.
Is there life outside Earth? And if so: how widespread is life in our universe? These are the big questions we want to answer in astrophysics.
We try to do this in three different ways. One of them is the high-resolution observation of exoplanets, that is, planets orbiting other stars. An exoplanet’s atmosphere could contain gases that indicate the presence of life.
You are listening out into space to see if a distant civilization is sending signals.
The second way is to look for external communication signals. You are listening out into space to see if a distant civilization is sending signals.
The third approach is to look for traces of biological activity in our solar system. This happened first on the moon, and then on Mars. Thanks to NASA’s Galileo mission, we’ve known since 1995 that there are also large amounts of water, and therefore potential habitats, in the outer solar system on the icy moons of the gas giants Jupiter and Saturn. Jupiter’s moon Europa, for example, contains twice as much water as all of Earth’s oceans combined.
Are there conditions on the moons of Jupiter and Saturn that make life possible?
The search for potential habitats – and even for life itself – on the moons of the outer solar system is currently a very active area of research. The questions one tries to answer are: Are there conditions that allow life to evolve? Where do these conditions exist on the moon? How can we better explore these places? And when promising evidence is found, how can we be sure it is, in fact, life?
The main mission trying to answer these questions is the Juice spacecraft, which was developed and built under the supervision of the European Space Agency and in which I am also involved. Joss embarked on her eight-year voyage into the Jovian system on April 14th. The probe’s main task is to study the habitability of Jupiter’s moons.
Once we determine more precisely which moon of Jupiter or Saturn is the most promising for life, the European Space Agency wants to send another mission to that moon. This mission will be equipped with specialized life detection hardware. It should be clear over the next year or two when this mission, which will cost around 1 billion Swiss francs, will begin its journey, where it will go and exactly how the search for life will take place.