Being able to say that life exists in other places, within or outside our Solar system, will fundamentally change our view on the role of humanity in the Universe. Is the Earth really unique as a cradle of life? We are in a position where we will find the answer in the next decades.
The enormous technological progress of the past decades has put us in a position to start examining the climate and the habitability of other worlds in detail. Within our own Solar System Mars and the icy moons of Jupiter and Saturn are particularly interesting through the (former) presence of liquid water. Studies of the physical and chemical boundaries, and hallmarks of habitability based upon studies of Earth and in the wider Solar System will enable extrapolation to exoplanets.
An important challenge will be to recognize and understand the chemical biomarkers on other worlds, where both climatological and geological circumstances and the biological processes may be significantly different. Future efforts will focus on in situ detection of biomarkers on planetary surfaces, as well as through remote sensing. The in situ search for biosignatures focuses primarily on biomolecules, organic compounds that life uses, and biominerals on and embedded in the surface, whereas remote sensing focuses on the detection of atmospheric markers that betray the presence of biological activity, such as oxygen and methane on Earth.
Very remarkable is current progress in research into exoplanets, planets around stars other than the Sun. Although the nearest stars are over a hundred thousand times more distant than Mars, scientists are getting ever better at not only finding new exoplanets, but also at characterizing their atmospheric properties (as well as the chemistry of planetary systems in formation).
The European Extremely Large Telescope (E-ELT) will play a central role in this effort. As a first step, the first-light instrument METIS (2024/25), which is being built under Dutch leadership, will examine the atmospheres of rocky exoplanets like the Earth for the first time. The next step is the development of the second-generation E-ELT instrument EPICS (2030/35), which can also detect biomarker gases. The Netherlands is playing a leading role here as well. Ultimately, a complete characterization of the atmospheres of terrestrial planets can only be realized with a specialized space telescope (2035+). All these technological developments will be realized in the framework of the European Space Agency (ESA), and of the European Southern Observatory (ESO).
The importance of collaboration with Dutch industry for this research path is evident and crucial. However, the benefits are equally important for this very industry. Ambitious explorative programs like the search for extraterrestrial life bring unique technological spin-offs, since the challenging specifications of their instrumentation lead to new technological developments.