The telescope that can change everything is ready to offer an unprecedented view of the universe

A time machine, a remarkable feat of engineering and technology or the launch of the decade are some of the comments that have been heard about the James Webb, the largest telescope ever sent into space; in Kurú, French Guiana, everything is ready for take off in the beginning tomorrow, Christmas day. After a few delays, it is scheduled to launch on an Ariane 5 rocket at 1:20 p.m., with a 32-minute window to launch.

The James Webb, with Spanish participation, will travel up to 1.5 million kilometers from Earth, approximately four times farther than the Moon. From there, will offer an unprecedented view of the universe at near-infrared and mid-infrared wavelengths, and will allow scientists to study a wide variety of celestial objects, being able to look back in time more than 13.5 billion years to see the first galaxies that were born after the Big Bang.

But for this, in addition to separating from the rocket at 27 minutes and 11 seconds, will have to go on a long journey and overcome a series of critical stages in the next month. The James Webb is so large that it has been folded in origami style to fit on the Arianespace rocket and once in space it will unfold like a transformer toy. Among others, it will have to open its parasol, the size of a tennis court, and then the primary mirror, 6.5 meters, with which it will be able to detect the faint light of stars and distant galaxies with a sensitivity one hundred times greater than that of the Hubble telescope.

All this in the first 29 days, but the engineers spend a minimum of six months calibrating the instruments so that the telescope is ready to do science. The James Webb is a collaboration between the space agencies of the United States (NASA), Europe (ESA) and Canada (CSA) and will face very low temperatures (around -230 degrees Celsius); It will work for a minimum of five years, although it is planned for ten years.

It will work in mid-infrared to observe cold objects, objects very far away and objects that are behind dust

It is designed to expand on Hubble’s scientific successes. Between the two telescopes, more than 30 years have passed and technologically they are very diverse: the size of the primary mirror (6.5 meters compared to 2.4 from Hubble) and its ability to see infrared light (invisible to the human eye) are the Main differences. Thanks to this, the James Webb will be able to look back in time and observe the first stars that existed in the early universe and how the first galaxies formed after the Big Bang and their evolution, in addition to the planets of our solar system and those that other stars orbit (chemical composition of exoplanets).

For this, it has incorporated four state-of-the-art scientific instruments that will provide the necessary data to analyze the materials that make up the stars, nebulae, galaxies and planetary atmospheres, explains ESA. In two of them, the MIRI (camera and spectrograph for the middle infrared) and the NIRSpec (spectrograph for the near infrared) there is Spanish science and several companies from the country participate.

The first is essential for the mission because thanks to the fact that it will work in mid-infrared it will observe cold objects, very distant objects -like the first galaxies- and objects that are behind dust, explains Macarena García, head of the equipment for this instrument at the Space Telescope Science Institute in Baltimore and a member of ESA’s science and operations team for the James Webb.

A different look at the universe

The NIRSpec you will be able to obtain spectra of more than 200 objects simultaneously and will study, for example, the properties and composition of the atmospheres of extrasolar planets. In addition, there are two other instruments, the NIRCam (near-infrared camera), which will search, among others, for supernovae in remote galaxies and light distortions due to dark matter, and the NIRISS (near-infrared camera and spectrograph without groove).

The telescope will equip astronomers and astrophysicists around the world, by hitherto impossible ways, with the necessary capabilities to expand the frontiers of knowledge about our solar system, the formation of stars and planets, and how galaxies are created and evolved. The universe has never been looked at with these eyes, so this look can be a milestone and a surprise.