Launch of new era: Leiden and James Webb telescope

Part I: How the Dutch helped build one of the most important instruments on board.

A key role is reserved for Leiden professor Ewine van Dishoeck. She has been involved with JWST from the beginning. In 1997, van Dishoeck was part of a small group of scientists that suggested the idea of sending a hyper-sensitive infrared instrument along. This became the Mid-InfraRed Instrument (MIRI): an infrared camera and spectrometer for which the Netherlands developed a large part of the optics and which will soon enable us to look right through cosmic dust.

A Dutch 'passenger' on board

Professor of Infrared Astronomy Bernhard Brandl was closely involved in the construction of MIRI. 'Unlike the other scientific instruments aboard, MIRI has not been designed and built by space agencies NASA and ESA, but by an international consortium of institutes,' he says. 'The Netherlands Research School for Astronomy (NOVA) was one of them.'

Brandl took part in many discussions and interactions, and also participated in the first test campaigns of the instrument. 'I guided the team that developed the medium-resolution spectrometer of MIRI,' he says. A spectrometer catches the light emitted by an object in space and separates it into different wavelengths, creating a 'fingerprint' that contains key information on these astronomical objects. Brandl: 'MIRI will be able to "see" light in the mid-infrared spectrum, with wavelengths invisible to the human eye.'

A giant leap forward

According to Brandl, MIRI is a giant leap forward. 'Such a powerful infrared spectrometer in space will be unique. It will enable us to look at cooler objects, which emit at these longer wavelengths. We will learn so many new things from the atmospheres of nearby exoplanets, to the evolution of distant galaxies. Furthermore, MIRI will allow us to analyse the spectra of different light points taken at once, which provides new research opportunities that would not have been possible with a classical spectrometer.'

As the successor to the beloved Hubble Space Telescope, Webb will have much more light collecting power - which equals more sensitivity and sharper images. 'Webb's angular resolution and sensitivity puts it way ahead of previous missions,' Leiden professor Marijn Franx points out. He was involved in the development of another instrument on Webb: NIRSPEC.

How are Earth-like planets formed?

As remuneration for their contribution, researchers involved in developing Webb will receive guaranteed observation time. Van Dishoeck wants to use her share to study the composition of the gas and dust in disks in which new planets are being born. This can then be compared with that of atmospheres of mature exoplanets, which are planets around stars other than our Sun. 'Compounds such as water, carbon dioxide and methane can only be observed in the infrared or from space,' she explains to the Dutch Financieel Dagblad. 'And thanks to MIRI, Webb will be able to pick up even the faintest infrared light.'

The composition of these atmospheres tells us more about the history of the formation of planets, but also, for example, whether there are planets that are similar to Earth or that contain more or less water and other building blocks for life compared with our own home planet.

The distant past

Franx will search for galaxies in the early Universe. 'They're very different from the ones we see nearby. We believe they are much more massive, contain many more stars, and are forming stars at a much higher rate,' he says. 'But we don't know very well what these stars are made of, or about their dust content. What kind of metals do they contain?.' Having more clues to questions like this can help us better understand the evolution of the Universe and the future of galaxies like our own Milky Way.