The day of the launch, several times delayed and scheduled for December 24, the pressure will be maximum in the Guyanese space center of Kourou. On board the Ariane V rocket which takes it into space, the 6.2 tons of the telescope but above all 10 billion dollars in investments and 30 years of work. If all goes according to plan, the new telescope is due to reach orbit six months later. It is located 1.5 million km from the Earth, at the Lagrange L2 point of the Sun-Earth system. This carefully chosen location gives the telescope an optimal position vis-à-vis the sunlight and the Earth. On the other hand, no repair will be possible so far.
30 years of work
What happened during the first hundreds of millions of years of the universe’s life? It was to learn more about this issue that the James Webb Telescope was designed at the NASA offices in the early 1990s, just after the launch of the first large space telescope named Hubble. At that time, scientists already knew that the light from the first stars, the photons that left over 13.5 billion years ago, hide in infrared waves. Hubble, orbiting the Earth, cannot see them. It is able to pick up only visible lights.
See the first galaxies in history
We must not forget that a telescope is in fact a kind of time machine. He observes the light emitted billions of years ago by distant stars. With the expansion of the universe, this light comes to us weaker and redder. By observing in the infrared, the James Webb telescope will therefore reveal a much older universe. For example, clouds of dust or the stars and planets are formed, but above all the first glow of the first stars and galaxies formed in the history of the cosmos.
With its 6.5 m diameter mirror and heat shield the size of a tennis court, #Webb is the largest space telescope ever developed. For this very special passenger, it was necessary to adapt # Ariane5. #WebbFliesAriane https://t.co/CkKPQ2iNIh
– CNES (@CNES) December 20, 2021
A jewel of technology
To unravel the mysteries of the first stars in the universe, the James Webb is a jewel of technology. It has a mirror 6.5 meters in diameter, the largest ever sent into space. Its 18 mirrors are covered with a thin layer of gold to improve its reflective power in the infrared. It is equipped with four instruments for observing wavelengths, one of which, the Miri, was designed in France.
All of these instruments make it the most powerful space telescope in history. And with his extreme sensitivity, he also promises discoveries in other areas of astronomy, on the origin of our solar system, exoplanets and black holes.