The most ambitious and costly telescope ever built was thrown into the air on Christmas Day, with the goal of looking deeper into the sky – and backward – than ever before.
After 30 years of planning and construction that has experienced several delays and rising prices, James Webb’s $ 10bn telescope is finally on its way to a special orbit, four times farther from Earth than the Moon.
One of the main objectives is to photograph the first stars and galaxies formed from the ancient atmosphere in the “cosmic dawn” about 200m after the Big Bang.
But astronomers also expect Webb’s telescope to offer valuable resources for our solar system, especially the planets – in our solar system and in orbits around the galaxy. Its equipment will measure the atmosphere, and it will search for living things.
Richard Ellis, professor of astronomy at University College London, has been involved in the project since the early 1990’s, when the US space agency NASA convened a scientific team to prepare a successor to Hubble’s observatory. just released. Named James Webb after NASA leader who led the Apollo program in the 1960s.
“It was very expensive, it was too late and Webb was threatened with multiple evictions,” Ellis said. “But now, now, we have a telescope that astronomers enjoy and are proud of.”
Webb’s 6.5-meter-tall glass makes it 100 times stronger than Hubble. But the main difference between the two major telescopes is that Hubble sees visible light, while Webb operates in the infrared environment. The latter is ideal for detecting distant objects because its light is transferred over long distances due to the spread of nature.
With Hubble located 550km above the Earth, Webb will be 1.5m km from the “Lagrange second point”, or L2. Here the gravitational force from the Sun and the Earth controls exactly the motion of the satellite, so that it appears to be floating in the same position in the sky.
The advantage of L2 in the orbit of Earth orbit is that its long distance from Earth makes Webb easy to keep cool and avoid being disturbed by Earth’s infrared radiation. One disadvantage is that it is far removed from the repair and maintenance work if there is a problem. Hubble was rescued from the embarrassment in 1993, when Shuttle’s astronauts installed a faulty mirror system.
Webb will take about a month to reach L2 once it is launched by the European Ariane 5 rocket. Along the way, it will unveil its first mirror, made of 18 gold hexagonal plates covered with gold beryllium coated gold, and a large sunscreen, which is as big as a tennis court and will keep the telescope in permanent shade at the expected temperature. -233 C.
But even this isn’t cool enough for one of Webb’s four devices, the infrared central device, or MIRI. It will be lowered to -266C, just seven degrees above zero, and cryocooler. “It works just as well as your home refrigerator, except that the cooler is helium, which is liquid at a much lower temperature,” said Gillian Wright, director of the UK Astronomy Technology Center in Edinburgh and director of the MIRI team.
MIRI will play a key role in detecting early starlight through dark dense galaxies at dawn and analyzing the atmosphere of distant planets. But when asked what he really hoped for, Wright replied: “I am thrilled to have found the most amazing thing. We have never had an infrared central device like MIRI in the air and it will find things we do not know here. “
Wright added that Webb and its equipment will be working in succession in April and May to see if all goes well. Astronomy is the beginning of July.
The Space Telescope Science Institute in Baltimore has been allocating time to astronomers at Hubble for 30 years and will do the same at Webb. Opportunities are so extensively registered that their peer-reviewed approach is used to select who should be available, some are reserved for scientists with the equipment to build a telescope.
Wright said his team would take a closer look at a small celestial body that Hubble had previously studied called Hubble Deep Field to look at the weakest and most original galaxies. “We also have a huge space program,” he said. Another question that scientists want to answer is how exoplanets – stars around our galaxy — are made up of cosmic dust.
Although the launch of Christmas Day from Kourou, French Guiana, went well, astronomers had to endure what Ellis called “a few months of hardship” as they waited for Webb to complete his gruesome and instrumentalist program.
If the telescope comes in the right order, it promises great scientific benefits – a celestial Christmas gift that should last for ten years.
Says Ellis: “I have been working to reconstruct the first galaxy of galaxies. “Seeing the ‘natural dawn’ with Webb will be the end of my career.”