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James Webb Space Telescope: “It will open up new possibilities”

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Scientists hope to take a look back at the early days of space after the Big Bang 13.8 billion years ago. On images of stars that are older than our solar system and may no longer exist. Possibly even evidence of a second earth, a blue planet.

With the launch of the James Webb Space Telescope (JWST) planned for autumn, researchers expect completely new insights. “It will simply open up gigantic new windows and new possibilities,” says the director for science at the European space agency ESA, Günther Hasinger.

The start of the approximately ten billion dollar project by the US and Canadian space agencies NASA and CSA as well as ESA had been postponed again and again. Now the gigantic telescope is to take off on board an Ariane launcher in autumn and fly far deeper into space with its four infrared instruments than its predecessor, the Hubble space telescope, which has been in operation for more than 30 years.

But this harbors a risk: While Hubble was repaired and serviced several times with shuttle flights at an altitude of 500 kilometers, this is no longer possible with the “James Webb Space Telescope” at a distance of 1.5 million kilometers. According to Hasinger, the telescope with its 6.5-meter mirror and a sunshade the size of a tennis court needs more than 130 individual mechanisms to unfold. “It’s a very, very complicated game that has to go on before everything is unfolded.” He compares it to a butterfly: “The caterpillar pupates, and then the pupa breaks open and the butterfly unfolds.”


The main mirror of the telescope
(Image: NASA)

This process begins on the way to the goal. “There are five points in the solar system at which gravity cancel each other out,” says Hasinger. The destination is one of them. There, with the earth and sun behind them and with the awning protected from heat radiation, the instruments could begin their measurements in different infrared waves. For this they are partly cooled down. “It will be the first cold telescope. If you want to measure infrared rays, which is heat radiation, then the telescope itself has to be very cold,” says Hasinger.

It will take about seven months for the first examinations. Hasinger believes that the first pictures will probably be seen next July. According to the institute, an instrument co-developed by the Max Planck Institute for Astronomy in Heidelberg, a combination of camera and spectrograph, is so sensitive that it could detect a burning candle on a Jupiter moon.

“Dense molecular clouds with a lot of dust and gas are the creation areas of new stars and planets. The dust, however, absorbs the visible light we are familiar with by sight, and it is therefore difficult or impossible for us to study their inner regions in detail,” says Klaus Jäger from dem Max Planck Institute. For the longer-wave infrared light, dust is a much smaller obstacle. “Observations in the infrared therefore allow us to look into these areas or to receive the infrared radiation from within.”

According to Hasinger, a deep survey of the early expanding universe and a search of the star formation areas are planned with the telescope. “But then a large part of the observation time will go to the extrasolar planets.” The telescope could examine the atmosphere of such exoplanets for molecules that may indicate biological activity. “Whether that succeeds or not, of course, depends on whether we find the right planets.”

The strength of the telescope lies in its spectroscopy – that is, that you can take a chemical fingerprint from any point in the sky. “A picture is beautiful to look at. What we get with the James Webb is that we can read 1000 other pieces of information in every single picture element,” says Hasinger. For example, whether water is even possible anywhere. Near-Earth planets are of course interesting. “At some point you would like to find a planet that is as Earth-like as possible and where water exists and which is close enough that future generations might be able to fly there.”