The new space telescope can look further back in time and should be able to revolutionize our knowledge of the universe. A large and advanced mirror will capture the light from the first stars and galaxies formed after the Big Bang.
Scientists guarantee that James Webb – as the new space telescope is called – will take even more spectacular pictures than the Hubble Telescope, which was launched just over 30 years ago and has had an impressively long life.
The development of James Webb has been going on for about the same time.
Now it is the intention that the telescope will finally be launched – according to the plan on Christmas Day.
– The launch of James Webb has been 14 years delayed and the project has become 28 times more expensive than the original price, says Pål Brekke at the Norwegian Space Center.
– The development of the telescope was started in the late 1990s and was planned to be launched in 2007 with a total cost of 500 million dollars. Several technical challenges and problems in financing the construction have delayed the launch. The entire project was close to being canceled in 2011.
–James Webb (the name comes from NASA’s former top executive) should be able to give us the “news” much faster than the Hubble Telescope, because it has a mirror with a diameter of not less than 6.5 meters, while Hubble has a 2.4 meter large mirror.
– James Webb wants to revolutionize astronomy and our knowledge of the universe. The telescope will look further into space than ever before, take pictures and analyze exoplanets, stars and galaxies, says Pål Brekke.
The study of the beginning of the universe will be a major task for the new telescope. Since the universe is 13.8 billion years old, we can only learn something about it by studying galaxies where light has been 10-13 billion years along the way.
–It is a long journey for light, so the very first galaxies are seen in even large telescopes only as some very faint patches of light.
Because the James Webb Space Telescope (JWST) has a much larger mirror, this telescope should be able to collect light to view these first galaxies much faster than Hubble.
But first, the new telescope will be ready for use. Pål Brekke explains:
– The telescope is folded, because otherwise it would not fit in the rocket. When all the different parts have to be unfolded again, a lot can go wrong. There is no way to repair things if something goes wrong – unlike the Hubble Space Telescope.
Brekke says that more than a thousand people from 17 different countries have participated in the construction, construction, testing and launch of the telescope.
But not least, there are thousands of scientists who have been waiting for many years for the images from the new space telescope.
– There are therefore many who want to breathe a sigh of relief on the day the telescope has unfolded and arrived at its new home in orbit around Lagrange point number 2. This point is located approx. 1.5 million km from Earth, always on the opposite side to the Sun. Here, James Webb will go in a fairly stable path without having to use a lot of fuel, says Pål Brekke.
–– One of the first things that happens after the telescope has come up in space, is that the huge sunshade unfolds. It should help keep the telescope super cold since the instruments in the telescope will not be able to observe if it is not very cold.
– The sunshade measures 21 x 14 meters – much like a tennis court – and consists of five layers of separate layers with fabricated kapton, a very thin, strong plastic material. Each layer is coated with a highly reflective metal surface. Each layer is thinner than half of a sheet of paper.
It is of course an engineering feat to unpack such a huge sunshade – made of ultra-thin layers – of telescopic poles. Therefore, engineers will hold their breath when it is “unpacked”.
– The temperature on the shadow side of the sunshade will be minus 225 C. For one of the instruments this is also too “hot” and it must be cooled further using liquid helium to minus 266 C, only seven degrees above the absolute zero point, says Pål Break.
The next critical phase is when the telescope itself is to be unfolded.
– The main mirror consists of 18 hexagonal segments, each with a diameter of 1.32 meters. They are made of beryllium which is strong and light – each segment weighs only 20 kg. They are further coated with a thin layer of pure gold, which effectively reflects infrared light.
In total, the mirror has a collection area of approximately 25 square meters. It’s about seven times the size of the Hubble mirror.
– Each segment of the mirror can be fine-tuned using small pistons behind the mirrors and can be adjusted with an accuracy of one ten thousandth of a human hair thickness, says Pål Brekke.
He also says that the telescope is so sensitive that it should be able to observe the heat radiation from a bee at the Moon’s distance or detect a candle on one of Jupiter’s moons – about 800 million km away.
The telescope will follow the earth’s orbit around the sun and will constantly turn the back of the sunshade towards the sun. Even the faint heat radiation from the earth or the moon will interfere with the measurements of distant celestial bodies without such a sunshade.
Pål Brekke at the Norwegian Space Center is aware that James Webb is much more than an upgrade of the Hubble Space Telescope.
– The much larger mirror will collect more light so that more distant objects can be observed and give us sharper images. Equally important is that James Webb will observe infrared light from the universe – radiation we cannot see with our eyes. This is what we often call heat radiation. Many people have probably seen pictures taken with thermal cameras. When observing infrared radiation, one can not do this in orbit around the Earth such as Hubble, but one must be far away from the earth and other light sources.
The point of it? Yes, that we should be able to see in mists and clouds of dust where new stars – with associated planets – are born.
Pål Brekke also believes that James Webb will be able to give us better answers as to whether any of the thousands of exoplanets we have discovered in recent years can be home to living organisms.
In other words, we can get one step closer to finding out if we are alone in the universe.
– James Webb can also look further back in time. The light from the first stars and galaxies formed after the Big Bang no longer exists as visible light. As the universe expands, this light has been stretched and is now visible only as infrared radiation. James Webb is thus almost like a time machine to count and will give scientists access to the entire history of the universe, says Pål Brekke at the Norwegian Space Center.
–
