Because one mistake can be fatal, the engineers leave nothing to chance. Everything has been exhausted and tested to the last. Partly because of this, the mission was often postponed. “Careers depend on it,” emphasizes Peter Rumler, project leader James Webb at ESA, from French Guiana. “People have spent a good part of their lives working on this.”
‘You only take such a step forward once every 30 years’
Webb’s mirror has a diameter of 6.5 meters, almost three times as wide as the Hubble. This allows the telescope to look sharper and more sensitively. There are four instruments on board that analyze the collected light, including the partly Dutch MIRI.
“You only take such a step every thirty years,” says Ewine van Dishoeck, professor of molecular astrophysics at the University of Leiden, who has been working on the project for 24 years. “We are building this telescope not just for ourselves but for new generations of researchers, my scientific children and grandchildren.”
Webb is going to look deeper into the universe than ever before. Hubble has already had an extreme deep fieldphoto”, says astronomer Lucas Ellerbroek. “You then aim the telescope at a boring piece of space where nothing can be seen. If you wait long enough, all galaxies will appear.” These galaxies are 13.2 billion years old and come from the early days of the universe. Webb looks even further, and therefore further back in time. “To really the oldest light from the young universe.”
Planets outside our solar system
Scientists who study planets outside our solar system – so-called exoplanets – are also enthusiastic. With James Webb they want to discover more about these worlds. What kind of atmosphere do they have? How hot is it there?
You can find this out by looking at starlight that has passed through a planet’s atmosphere. If there is water or carbon dioxide there, those substances absorb certain wavelengths of light, which are then missing. This can only be investigated from Earth for the largest planets. With Webb it should be possible to look at smaller worlds that are more like Earth.
Twenty years of lying awake
Scientists still have many questions about exoplanets. Are there continents or building blocks for life? Webb can only find indirect indications for this. “In my life, we are never going to take a real photo of an exoplanet, we only see a bright spot,” says Ignas Snellen, professor of observational astrophysics at Leiden University. He does think that it will become increasingly clear whether our solar system is special or just ordinary.
But first it’s nail biting. Many things can still cause the mission to fail. “We have been awake for twenty years about this,” says professor Van Dishoeck. She herself will investigate the clouds from which stars and planets form. “The first time you get data is always a special moment. I don’t care what it is, it’s just a gift and a surprise when you open it.”
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