NASA launched its most powerful telescope, the $10-billion James Webb, into space on Saturday. The Hubble successor is expected to help scientists find answers to questions about extraterrestrial life and processes in the early universe.
Project nearly cancelled
"The James Webb was nearly 25 years in the making. It was supposed to go into space in 2014, but the developers were behind schedule, affected by the huge costs. As a result, the launch was postponed several times. The U.S. Congress even wanted to close the project several times, because its assembly simply did not fit into the budget.
In early September, it was announced that the launch would take place on December 18, but it was postponed again by a week - until December 25. The long-awaited launch of Webb is being hailed as a real breakthrough and has high hopes for it. It is expected to be able to make 266 observations in its first year. Their total duration is estimated at six thousand hours. Researchers from 41 countries will be able to conduct research.
Infrared telescope
Initially, it was assumed that the James Webb would be able to measure how slow the expansion of the universe. However, after astrophysicists Adam Reece, Saul Perlmutter and Brian Schmidt made the discovery that it was expanding with acceleration, the telescope's operating principle was changed by making the instrument infrared.
Russian astronomer Denis Denisenko of the Department of Galaxy and Variable Stars of the Sternberg State Astronomical Institute in a conversation with "360" explained that the most distant objects in the universe are shifted to the red side relative to the visible range, so observe them in the infrared range is indeed most effective.
One of Webb's main features is its enormous mirror, which measures 6.5 metres in diameter. It is formed by 18 beryllium hexagons. A thin layer of gold was sprayed on each of them. Because of its record size, the mirror was folded during launch and its petals will only unfold in space.
"This mirror is not glass with aluminium, but beryllium with a gold coating. It works in a slightly different way to an optical telescope. That's the first difference. The second difference is that its mirror is not monolithic, but consists of 18 hexagonal cells, or segments. It's a well-known story that it's launched in a folded form - like the two sashes of a truce. They will be in the folded position, then they will unfold and have to form a single spherical surface to get an image in space," explained the expert.
According to Denisenko, the gold coating was chosen because it will make the telescope more reliable and durable. It is less affected by the conditions of open space, that is, Webb will be able to last longer than if its mirror was made of glass and covered with aluminum.
What the James Webb can see
One of the instruments that will absorb light reflected from the mirror is a near-infrared camera. With it, the James Webb will be able to see numerous stars, planets and the centres of galaxies in the Universe.
"It may even be possible to see even more distant objects - the youngest galaxies, the very first galaxies that were born long before the appearance of our Milky Way and the galaxies nearest to us," Denisenko said.
In addition, as emphasized by the scientist, "Webb" will find a solution to one of the biggest problems of modern astrophysics, namely the answer to the question of what came before - the core of active galaxies, aka quasars, or the active galaxies. What came first, supermassive black holes or the galaxies that fed those black holes before they became supermassive.
