The Mid-infrared ELT Imager and Spectrograph (METIS) is one the first three scientific instruments on ESO's Extremely Large Telescope (ELT). At the time of anticipated first light in 2025, METIS will provide diffraction limited imaging, coronagraphy and medium resolution slit spectroscopy in the 3-19 micrometers range, as well as high resolution (R approximately equals to 100, 000) integral field spectroscopy from 2.9-5.3 micrometers. The unique combination of these observing capabilities with an angular resolution of 0.020 sec, and the sensitivity provided by a 40m aperture, make METIS a very powerful tool to study the infrared sky - from objects in our Solar system, the Galactic center, brown dwarfs, evolved stars, and massive stellar clusters to active galactic nuclei (AGN), local starbursts, transient events, and luminous infrared galaxies at intermediate redshifts. Its main scientific focus, however, will be on the study of proto-planetary disks and exoplanets. In this paper, we describe the instrument concept and performance. We discuss the scientific performance of METIS with respect to AKARI, and elaborate on the relevance of the AKARI archive with respect to the METIS observing program.@en

In this White Paper, which was submitted in response to the European Space Agency (ESA) Voyage 2050 Call, we recommend the ESA plays a proactive role in developing a global collaborative effort to construct a large high-contrast imaging space telescope, e.g. as currently under study by NASA. Such a mission will be needed to characterize a sizable sample of temperate Earth-like planets in the habitable zones of nearby Sun-like stars and to search for extraterrestrial biological activity. We provide an overview of relevant European expertise, and advocate ESA to start a technology development program towards detecting life outside the Solar System. © 2021, The Author(s).@en