The project has been going on for three decades. After a long series of postponements, the launch is planned for Christmas Eve.
The James Webb telescope, named after a former Nasa chief, will pick up the thread after the legendary Hubble telescope. Scientists believe that it will be able to show humans what the universe looked like up to the beginning 14 billion years ago.
For that to be possible, they have had to build a completely unusual instrument.
The James Webb telescope is sensitive enough to see the heat signature of a hop on the moon, said one of the project’s founders, Nobel Prize winner John Mather. He is a cosmologist and astrophysicist.
Sensitivity at this level is necessary to capture the faint glow from the very first stars and galaxies that were formed.
Seeing the past
The universe is so vast that it is difficult to understand. The James Webb Telescope will examine the most distant objects that can be observed.
Since light takes time to move, examining distant objects is the same as observing the past. The dim light from the early universe has been moving for over 13 billion years before being captured by the space telescope’s sensors.
How far back we can see is determined by how sensitive the equipment is.
The Hubble Space Telescope, once a pioneer in the field, is sensitive enough to see events in space about 500 million years after the big bang.
Webb can look even further into the past. Scientists hope to be able to observe conditions 200 million years after the beginning of the universe.
Newborn galaxies
The expectations are high.
– This telescope is designed to answer the biggest questions in astronomy today, said astrophysicist Amber Straughn at Nasa in a TED lecture in 2017.
“With the James Webb Telescope, we can hope to observe these newborn galaxies and learn more about how they grow over time,” she continued.
One problem with telescopes on Earth is that the atmosphere creates blur and interference. The largest telescopes are located on high mountain peaks to minimize the problem.
By placing a telescope in space, the problem is completely circumvented. The view of distant stars and galaxies is unobstructed.
Are we alone?
Another important field of research for the new telescope will be exoplanets – planets orbiting distant stars.
Since the first exoplanets were discovered in the 1990s, a flood of discoveries has been made, and the number of confirmed discoveries is approaching 5,000. NASA’s Kepler space telescope contributed to 2,600 of them during almost ten years of operation, until it ran out of fuel in 2018.
The James Webb Telescope can both help to find more and reveal the secrets of those who have already been discovered. By capturing the light that shines through the atmosphere as a planet passes in front of a star, the telescope can provide answers to what it contains.
The ultimate goal is to find out if the earth is unique, or if there are similar planets where life may have arisen.
Researchers in line
– There is a lot of excitement, we have been waiting for this moment for a long time, says one of the researchers associated with the project, Pierre Ferruit from the European Space Agency (Esa), to AFP.
Esa and the Canadian space agency CSA are collaborating with Nasa on the space telescope, and Ferruit has worked with the telescope for much of his career – in the same way as thousands of other research colleagues.
The competition for observation time is already underway.
– The demand is very high. Esa has received over a thousand applications for the first year of operation alone, he says.
– Even after 20 years, the questions that Webb was made to answer are still just as urgent.
