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After five successive postponements, corresponding budget overruns and after 30 years have passed since its original design, the time has finally come, and on Christmas Day, to launch the James Webb Space Telescope, the successor to Hubble, the largest and most sophisticated telescope ever sent into space, opening a new era in astronomy and astrophysics.
This is a collaborative mission between the US space agency (NASA), the European Space Agency (ESA) and the Canadian Space Agency. The launch is scheduled to take place on a European Arian 5 rocket shortly after noon on Saturday, at 14:20 Cyprus time, from the European spaceport at Kourou in French Guinea in northeastern South America.
If all goes well, the $10 billion telescope will orbit the Sun at the second Lagrange point, or L2, staying at a roughly constant distance of 1.5 million kilometres from Earth, or about four times farther from the Moon. By comparison, the Hubble Space Telescope, launched in 1990, is one third of that distance from our planet (nearly 550 kilometres).
The James Webb is expected to reach the L2 point a month after its launch. Then, there will be a setup and adjustment period that will last six months. It is expected to start collecting data and making its first observations in mid-2022.
The telescope, built primarily by the US company Northrop Grumman and named after the head of NASA in the 1960s, is much more sensitive than Hubble and will see mainly in the infrared part of the spectrum, which will allow it to observe through clouds of dust and gas, while Hubble operates mainly in the optical and ultraviolet parts of the spectrum.
As Dr. E. Saridakis, principal investigator of the Institute of Astronomy, Astrophysics, Space Applications and Remote Sensing (IADET/EAA), the new telescope will provide improved infrared resolution and sensitivity compared to Hubble and will be used in a huge range of research in the fields of astronomy, astrophysics and cosmology, from the atmospheric characterisation of potentially habitable exoplanets, to the observation of some of the most distant and oldest events and objects in the Universe, such as the formation of the first galaxies.
James Webb has a mass of 6 tons and 6.25 times the collecting surface area, hence sensitivity, compared to Hubble. In addition, it has a significantly larger field of view, covering 15 times the area of the sky. Its primary mirror consists of 18 hexagonal sections, made of gold-plated beryllium, which unfold and adjust to form a 6.5 m diameter mirror. Its largest component is the five-layer solar shield, which reduces the solar radiation reaching the telescope by a million times and is the main reason for its large size (20 by 14 metres).
Unlike the Hubble telescope, which made observations in the ultraviolet, visible and near-infrared regions of the electromagnetic spectrum (0.1 to 1 μm), the James Webb will be able to take data in a lower frequency range, from long-wavelength visible light to mid-infrared (0.6 to 28.3 μm), which will allow it to observe high redshift objects, and thus much older and much farther away than Hubble could observe. Space telescopes have the advantage that they can make observations without the obstacle of the Earth's atmosphere. Saridakis, ia can observe the most distant objects in the observable Universe, looking 13.5 billion years back in time, recording the light of the first stars and galaxies after the Big Bang, thus allowing cosmological and gravitational theories to be tested. In addition, it will be able to observe the large black holes present at the centres of galaxies, providing evidence for their formation and evolution. It will also collect data on the formation of stars and new planetary systems, phenomena which, because they occur in dense clouds, are difficult to see. Another category of observations that James Webb will make are those related to exoplanets. Its spectrometers are able to collect and analyse the radiation that passes through the atmosphere of exoplanets in order to draw conclusions about their chemical composition and possible signs of life.
At the same time, the James Webb will also carry out observations in our own solar system, related to the atmospheres of planets and their satellites with atmospheres. It will be able to focus on the study of Jupiter and its satellites, especially Ganymede and Europa, with its possible oceans beneath the icy surface, Io with its hidden thiophyte volcanoes, and Saturn's satellite Titan with its hydrocarbon lakes.
Finally, as Saturn's rings, as well as those of Neptune, Uranus and Jupiter, are much better observed in the infrared, Webb is expected to provide a wealth of evidence about their formation.
Astrophysicist Dr Alexis Delivorias, a partner at the Eugenides Planetarium, says in a post on the Foundation's website that this is perhaps the most important space telescope of the next decade.
Having far exceeded both its original budget and its originally planned launch date, there have even been thoughts of cancelling the whole project. Fortunately for astronomical research, this did not happen, and the international scientific community is eagerly awaiting its successful launch and placement in orbit around a point about 1.5 million km away from Earth. With the data it will collect, it will help astronomers to investigate almost every era of the evolution of the Universe, from the first luminous structures formed after the Big Bang to the formation of planetary systems and the identification of exoplanets favourable for the emergence of life.
He points out that it will allow astronomers to penetrate regions that are opaque to optical telescopes, such as dust- and gas-filled stellar nurseries and newborn planetary systems. At the same time, however, it will collect data on the most distant galaxies in the Universe, making a crucial contribution to investigating the big cosmological questions that remain unanswered. With its penetrating gaze, it will take us even further into space and even further back in time than the now-aging Hubble, helping astronomers to greatly expand their knowledge of the creation and early evolutionary stages of the Universe's first stars and galaxies.
The launch will be covered live on NASA (https:/www.nasa.govasalive) and ESA (https:/www.esa.int/ESA_Multimedia/ESA_Web_TV) television, and can also be followed via Facebook (https:/www.facebook.com/events/305381571443979), YouTube (https:/www.youtube.com/channel/UCIBaDdAbGlFDeS33shmlD0A) and other applications. A related video is available on YouTube: https:/www.youtube.com/watch?v=XR-UQcXMysE IDP Attached is a photo of the James Webb Telescope
Source: CNA
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