The Hubble Space Telescope, the most innovative observatory of its era, was designed with many things in mind. Mark McCaughrean, senior advisor for science and exploration at the European Space Agency, told Space.com that stars and galaxies existed a few hundred million years after the Big bang.
They didn't have the technology to make Hubble see them, even if they had known about them.
McCaughrean said that Hubble had a lot of top line goals, many of which were 20 years old. Science had changed by the time they built it. Astronomers discovered in the 1980s that the galaxies formed much earlier than expected.
The James Webb Space Telescope works in pictures.
It became obvious that a grander space observatory was needed to get to the early stars and galaxies that lit up the universe after hundreds of millions of years of darkness.
The technology that would allow this observatory to see the first light in the universe had yet to be developed.
The power of the eyes.
The faint light coming from the early stars and galaxies would be collected by the detectors that were missing.
The Hubble was built to detect light. The wavelength of the visible light from these early galaxies is stretched into the part of the spectrum called the redshift because they are so far away.
McCaughrean was a PhD student at the University of Edinburgh when he was involved in the development of the early infrared detectors that are now used in the James Webb Space Telescope.
McCaughrean said that in the 1980s, one detector was used to take pictures of the sky. It took a long time. My thesis was about the first camera that could take 2D images. We had 58 times as many as everyone else, because they only had one.
McCaughrean moved to the U.S. to work on the NearInfrared Camera and Multi-Object Spectrometer (NICMOS), the first detector fitted on the Hubble Space Telescope during its second servicing mission in 1997. The first door for Hubble into the universe was opened by the NICMOS detectors.
The sun will be 1 million miles from Earth. The image is from the European Space Agency.
The technology has come a long way since Hubble's early years, and the James Webb Space Telescope project has been pushing it further along the way.
The detectors on the JWST have 2000 by 2000 words. McCaughrean said that they have lots of them. "We have a lot more of the same things as Hubble did when it was launched."
What will the James Webb Space Telescope be able to do, in combination with all the other aspects of the mission that make it so ground-breaking?
Four cutting edge instruments designed to analyze the chemical composition of the near and distant universe will be created by the James Webb Space Telescope. This is done using a technique called spectroscopy, which looks at how matter in the universe absorbs light. Astronomers will be able to reconstruct what stars, nebulas, galaxies and planets are made of when different chemical elements absorb light at different wavelength.
The James Webb Space Telescope instruments are 10 to 100 times better than anything previously available, according to Randy Kimble, the project scientist for integration, test and commission at NASA's Goddard Space Flight Center. There is an advantage of 1,000 in some of the mid-infrared wavelength.
The farthest reaches of the universe can be seen with the improved resolution of IR. Kimble, who worked on instruments for the Hubble Space Telescope and the Wide Field Camera 3, said that where the Hubble Space Telescope could provide only a rough estimate of an ancient galaxy's age and chemical composition, the new telescope will deliver with precision.
NASA's previous telescope, called the Spitzer, was much smaller and less sensitive. The image is from NASA/JPL-Caltech.
The early star and galaxy formation is not untangled.
Some of the best views into the early universe were opened by the Wide Field Camera 3. Kimble said that Webb is now positioned to surpass that legacy.
Kimble said that the Wide Field Camera 3 runs out of wavelength. It will be interesting to see which ones turn out to be correct, as some of those detections get kind of iffy. It will be possible for Webb to say that we see this particular galaxy 250 million years after the Big bang.
McCaughrean says Hubble can see up to 13 billion years into the past. It already sees that the evolution of the galaxies may have created several generations of stars.
McCaughrean said that the material must have been made by stars we haven't yet seen. You may have had lots of generations of massive stars after 500 million years because big stars form and die quickly.
The universe was very different in the first hundreds of millions of years after the Big bang. Dana Berry created the art for the NASA/WMAP Science Team.
The evolution of the universe is chemical.
The Royal Observatory in Edinburgh has a scientist who is interested in what happens when early stars die and their material is released into the environment to give birth to new stars. The chemical composition of the early universe was very different from what we see today. Jones told Space.com that it only contained hydrogen, helium and a small amount of lithium. The other chemical elements that we see today were cooked up inside the stars.
Jones said that a lot of the chemical synthesis in the universe can be found around low mass stars in their final stages of evolution. Slow process chemistry can happen in their atmospheres because of the temperatures and pressures. It's fascinating to me how we can go from having only three chemical elements to the diversity we see today.
The chemical kitchens of the early galaxies will be examined by the James Webb Space Telescope, as well as the fertilization of the wider universe with the explosion of powerful supernovas.
Jones said that the real power of Webb was spectroscopy. We will be able to view individual objects with the high resolution that we will get with the help of the Webb system.
The region is known for its star-forming activity. The dust will be visible through the telescope's heart. M. Robberto is a member of the Hubble Space Telescope Orion Treasury Project Team.
Peering into the hearts of star-forming regions.
The Hubble Space Telescope and the James Webb Space Telescope will reveal different aspects of the universe. While Hubble's strength is in looking at the visible universe, the telescope will be able to see through dust in the center of the universe.
McCaughrean said that stars are being born in places like the Orion Nebula. Dust absorbs optical light, so we couldn't see into them.
The previous telescopes were much smaller than the one we have today. They only glimpsed the star-forming regions in a limited resolution when they saw as far as Webb.
Jones said that before, when we could see the site of star formation, we would see multiple objects all mushed together. Webb will be able to separate them all. We would be able to see multiple stars being born in clusters.
Astronomers have been able to map star-formation in our own galaxy, but the James Webb Space Telescope will take out star birth centers in far away reaches of the universe.
"We will see more distant, more extreme galaxies, where the environment is very different from what we see in the Milky Way," said Jones. We used to only be able to see stars about 8 times the mass of the sun, but now we should be able to see the formation of stars about the size of the sun.
The comets and asteroids that made up the Kuiper Belt will be looked at by the James Webb Space Telescope. The image is from NOIRLab/NSF/AURA/J. da Silva.
There is an outer solar system.
It won't be all about far away places. Scientists interested in Earth's more local neighborhood will also have fun with him.
McCaughrean said that we can't look inwards towards the sun, but we will be able to look out. We can see planets like Mars, Jupiter, Saturn, Uranus and Neptune in the Kuiper Belt.
The outer solar system is surrounded by comets, asteroids and other debris in the Kuiper Belt. It's a dark and cold region and it's difficult to explore because of the objects.
McCaughrean said that theJWST can do fantastic spectroscopy. The objects are cold and don't reflect much light, so you need a big telescope. We hope to be able to see the ices and various molecule on their surfaces.
There are other planets.
Since the conception of the James Webb Space Telescope, new areas have emerged that may not have been foreseen when the first light machine was first conceived. The first two planets were discovered in 1995. Thousands of exoplanets of various sizes have been found. While not designed with these potential other Earths in mind, the James Webb Space Telescope is able to tell us much more about their nature than any other mission before.
McCaughrean said that the planets have atmospheres that have different types of molecule in them. Carbon dioxide, oxygen, and nitrogen are things. It's best to look at the molecule through the use of the IR.
The NearInfrared Camera (NIRCAM) is fitted with extra implements called coronographs, which block out the light of a star to see more clearly what is happening around it. It might involve alien systems of planets with water and atmospheres that could support life.
"Thirty years ago, nobody would have thought that we could study the atmospheres of planets around other stars," said Kimble. "Now we are doing it frequently, and we are going to do that much better."
The unknowns.
The James Webb Space Telescope changed astronomy. Many of its most ground-breaking discoveries may come from areas that are completely unknown today.
Kimble said that Hubble and the other general purpose observatories are exciting. They have a broad range of capabilities that allow them to make discoveries that are not in the areas that you designed the telescopes for. Half of Hubble's top 10 hits were things they knew they were building for and half were things that people had no idea about. I hope that will be the case for Webb.
Jones was only a little girl when the James Webb Space Telescope was conceived, but she will be able to uncover the great unknowns for decades to come.
Jones said that the James Webb Space Telescope will change the view of the universe. It's only thanks to people who thought about it when I was younger that I can now make the most of it.
The space Telescope Instruments of James Webb.
The NIRCAM is a camera.
The light from the earliest stars and galaxies will be detected by NIRCam. The camera is fitted with some extra implements called coronographs. The coronographs will allow the astronomer to see what's happening around a star, which is great for discovering exoplanets.
The NIRSpec is a Near InfraRed Spectrograph.
The main tool for cracking the chemistry of the universe is NIRSpec. It will reveal the properties of the observed objects, including their temperature, mass and chemical composition.
The light coming from these objects will be very faint, so the James Webb Space Telescope will have to stare at them for hundreds of hours. NIRSPec will be able to observe 100 distant galaxies at the same time.
McCaughrean said that it lets you open doors and let the light through from one galaxy, but then block off all the light from everything else. You can open 100 doors at the same time. That is very sophisticated and has never been flown in space.
The Mid-Infrared instrument is used in the detection of light.
MIRI is a combination of a camera and a spectrograph, but unlike the previous two, it observes in the longer wavelength of the mid-infrared part of the spectrum, which will make it a go-to instrument for anyone looking to study comets and asteroids. The Hubble Space Telescope turned into a legend due to the images of MIRI.
The Fine Guidance Sensor and Slitless Spectrograph are used.
FGS/NIRISS will help to detect the first light, spot exoplanets and analyze their chemistry.
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