The universe unveiled

SPICA has been designed to be extremely sensitive to infrared radiation. Unlike visible light, infrared radiation is not absorbed by the dust that pervades the universe – as a result, observations in the infrared literally unveil the hidden universe, allowing us to see deep into the inner reaches of galaxies, star forming clouds and planet forming systems.

One of the big questions in astronomy is which processes regulate the formation and evolution of galaxies. Early in the history of the Universe, about twelve billion years ago, the first stars and galaxies started forming. In the next few billion years the process of formation and evolution sped up, becoming increasingly more efficient until that activity peaked about nine billion years ago, and since then the production of these megastructures has been slowing down continuously. The cause for the increase, peak and subsequent decrease of galaxy formation efficiency is still the subject of speculation. With SPICA spectral ‘fingerprints’ will be taken for many thousands of galaxies spread over cosmic time. With these fingerprints we will be able to accurately probe the physical conditions in and around these galaxies, and thus determine which are the factors that govern the formation and evolution of galaxies.

 

In the nearby universe SPICA will provide detailed insight into the formation processes of stars and planetary systems. These occur deep inside dense dusty clouds of matter and can only be studied in the infrared. Equally, observations of  the infrared spectral fingerprints of ions, atoms, molecules, dust grains and ices  allow astronomers to probe not only the physical conditions in and around planet forming disks, but also to establish where in the planet forming disk molecules like water are solid or gaseous, and thus  will chart the ‘snowline’. By combining these results with observations of dust rings around full-grown planetary systems the link can be made to the solar system and its dust ring, the so-called ‘Oort cloud’; in this way SPICA will yield valuable clues to the formation of our own planetary system.

 

SPICA candidate

The SPICA proposal was submitted to ESA in 2016 by a large international consortium, with partners from 20 universities and institutes (including Stockholm University)  from Europe, North America and Asia, as a response to the fifth call medium scale mission proposals for ESA’s ‘Cosmic Vision’ programme. Along with the SPICA 25 mission proposals were submitted by different European-led consortia. Of these 25 only SPICA and two other proposals have been selected for the last round, in which three parallel detailed studies will be undertaken to establish which mission provides the best balance between scientific results and technical feasibility. It is expected that in 2021 the final decision will be taken as to which of these three projects will be implemented as ESA’s M5 mission for launch at the end of the next decade.