The Hubble Space Telescope‘s launch in 1990 played a huge role in extending our fundamental understanding of the universe. Hubble took humanity to one of its greatest adventure ever. Not just the Hubble, but the Spitzer Space Telescope too did the same for mankind. But these new discoveries led us to plenty of new questions that cannot be solved by the present capabilities of the telescopes up there.
James Webb Space Telescope (JWST) is scheduled to launch into space on 30th March of 2021 with a goal of carrying out the legacy of Hubble and to answer all the queries. Webb will be the largest, most powerful and complex space telescope ever built and launched into space. Unlike the Hubble, which observes in the near ultraviolet, visible, and near-infrared (0.1 to 1 μm) spectra, the JWST will observe in a lower frequency range, from long-wavelength visible light through mid-infrared (0.6 to 28.3 μm), which will allow it to observe high redshift objects that are too old and too distant for the Hubble to observe.
Webb telescope weighs 6 metric tons and will orbit 1.5 million kilometres from Earth. Webb also holds a much bigger mirror than Hubble. It is a 21 feet 4-inch (6.5 meters) diameter primary mirror, which would give it a significantly larger collecting area than the mirrors available on the current generation of space telescopes.
Recently, NASA tested JWST by commanding the spacecraft’s internal systems to fully extend, and latch its iconic primary mirror into the same configuration it will have when in space. The spacecraft was able to move and unfold as intended.
“Deploying both wings of the telescope while part of the fully assembled observatory is another significant milestone showing Webb will deploy properly in space. This is a great achievement and an inspiring image for the entire team,” said Lee Feinberg, optical telescope element manager for Webb at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
“Hubble, when pushed to its maximum, could see galaxies that were teenagers in terms of age. We want to see babies,” says astrophysicist Blake Bullock, who is a director at Northrop Grumman Aerospace Systems, the contractor on the project. “With the Webb, we will be able to see back in time to the earliest objects in the universe for the first time. Also for the first time, we will be able to characterize other planets going around other stars, distant exoplanets, and see if there are oceans, an atmosphere, what chemical elements are there.”
It is evident from her statement that JWST has some tremendous amount of goals. Let’s check out a few from these goals.
1.Studying the stellar nursery in the Orion Nebula
JWST aims to study about a bustling stellar nursery in the Orion Nebula. Webb will survey an inner region of the nebula called the Trapezium Cluster. This cluster holds the shelter for around a thousand infant stars. All these stars are crowded into space only 4 light-years across.
Mark McCaughrean, the Webb Interdisciplinary Scientist for Star Formation, the man assigned to lead this team says “That’s a location where there are many very young stars that are around a million years old. A million years may not seem very young, but if our solar system were a middle-aged person, the stars in this cluster are just babies, three or four days old. So there are all sorts of interesting things going on with them that we don’t see in the older stars around us today. We’re very interested in understanding how stars and their planetary systems develop in the very earliest stages.”
McCaughrean and his team have three main objectives:
- Survey the distribution of the masses of young objects in this cluster.
- Examine the very earliest phases of planet formation around the cluster’s young stars.
- Study the material many of the young stars are ejecting in jets and outflows.
The infant stars are surrounded by the gas and dust from which they are being made. So it’s hard to observe such stars using visible wavelength. But they are often still observable in the infrared since long-wavelength light can penetrate the dust.
2.Examining the Ice Giants :Uranus and Neptune
Uranus and Neptune are the least-explored of planets in our solar system. Only Voyager 2 has visited these ice giants. This event helped us in understanding more about them. Unfortunately, Voyager 2 was unable to answer all the questions we had and left many more questions than before. Scientists are planning to answer all these by studying the circulation patterns, chemistry and weather of Uranus and Neptune in a way only Webb can.
“The key thing that Webb can do that is very, very difficult to accomplish from any other facility is map their atmospheric temperature and chemical structure,” explained the studies’ leader, Leigh Fletcher, an associate professor of planetary science at the University of Leicester in the United Kingdom. “We think that the weather and climate of the ice giants are going to have a fundamentally different character compared to the gas giants. That’s partly because they’re so far away from the Sun, they’re smaller in size and rotate slower on their axes, but also because the blend of gases and the amount of atmospheric mixing is very different compared with Jupiter and Saturn.”
These studies will be conducted through a Guaranteed Time Observations (GTO) program of the solar system led by Heidi Hammel, a planetary scientist and Webb Interdisciplinary Scientist. Fletcher advises being prepared for seeing phenomena on Uranus and Neptune that are totally unlike what we’ve witnessed in the past.
“Webb really has the capability to see the ice giants in a whole new light. But to understand the continual atmospheric processes that are shaping these giant planets, you really need more than just a couple of samples,” he said. “So we compare Jupiter to Saturn to Uranus to Neptune, and by that, we build up a wider picture of how atmospheres work in general. This is the beginning of understanding how these worlds are changing with time.”
Hammel added, “We now know of hundreds of exoplanets — planets around other stars — of the size of our local ice giants. Uranus and Neptune provide us with ground truth for studies of these newly discovered worlds.”
3.A Gaze into the Birthplaces of Massive Stars:
Highly massive Stars often die young. They usually end their short lives in violent explosions called supernovae, but very little is known about their births and these birth regions. In 2021, shortly after the launch of NASA’s James Webb Space Telescope, scientists plan to study three of these clouds to understand their structure. They are:
- The Brick: One of the darkest infrared-dark clouds in our galaxy, this roughly brick-shaped cloud resides near the galaxy’s centre, about 26,000 light-years from Earth. More than 100,000 times the mass of the Sun, the Brick doesn’t seem to be forming any massive stars—yet. But it has so much mass in such a small area that if it does form stars, as scientists think that it should, it would be one of the most massive star clusters in our galaxy, much like the Arches and Quintuplet clusters, also in the neighbourhood of the galaxy’s centre.
- The Snake: With a name inspired by its serpentine shape, this extremely filamentary cloud is about 12,000 light-years away with a total mass of 100,000 Suns. Scattered along the Snake are warm, dense dust clouds, each containing about 1,000 times the mass of the Sun in gas and dust. These clouds are being heated by young, massive stars forming inside of them. The Snake may be a section of a much longer filament that is a “Bone of the Milky Way,” tracing out the galaxy’s spiral structure.
- IRDC 18223: Located about 11,000 light-years away, this cloud is also part of a “Bone of the Milky Way.” It shows active, massive star formation happening in one side of it, while the other side seems completely quiet and unperturbed. A bubble on the active side is already starting to destroy the initial filament that was there before. While the quiescent side has not started forming stars yet, it probably will soon.
“What we’re trying to do is look at the birthplaces of massive stars,” explained Erick Young, principal investigator of a program that will use Webb to study this phenomenon. He is an astronomer with the Universities Space Research Association in Columbia, Maryland. “Determining the actual structure of the clouds is very important in trying to understand the star formation process,” he said.
4.A Search for Potentially Habitable Exoplanets:
The star TRAPPIST-1 was first discovered in 1999 by astronomer John Gizis and colleagues. Astronomers using NASA’s Spitzer Space Telescope and ground-based telescopes discovered that the system has seven planets. Three of these planets are in the theoretical “habitable zone,” the area around a star where rocky planets are most likely to hold liquid water. JWST will observe those worlds with the goal of making the first detailed near-infrared study of the atmosphere of a habitable-zone planet. There are more than one team of astronomers will be assigned to study the TRAPPIST-1 system with Webb.
“It’s a coordinated effort because no one team could do everything we wanted to do with the TRAPPIST-1 system. The level of cooperation has been really spectacular,” explained Nikole Lewis of Cornell University, the principal investigator on one of the teams.
Transmission spectroscopy is going to be used to find signs of an atmosphere over there. They will look for the appearances of any transits in the spectrum. In addition to examining planets using transmission spectroscopy, the teams will also employ a technique known as a phase curve. This involves observing a planet over the course of an entire orbit, which is only practical for the hottest worlds with the shortest orbital periods.
Since the exoplanets are so far away, scientists cannot look for signs of life by visiting these distant worlds. Instead, they must use a cutting-edge telescope like Webb to see what’s inside the atmospheres of exoplanets. One possible indication of life, or biosignature, is the presence of oxygen in an exoplanet’s atmosphere. In a new study, researchers identified a strong signal that oxygen molecules produce when they collide. Scientists say Webb has the potential to detect this signal in the atmospheres of exoplanets.
5.Continuing Spitzer’s Legacy:
After more than 16 years of exploration, NASA’s Spitzer Space Telescope wound up its mission on 30th January of 2020. Spitzer has made its journey beyond alluring with its amazing discoveries such as planets outside our solar system, called exoplanets, and galaxies that formed close to the beginning of the universe. Many of these discoveries will be studied more precisely with the use of the James Webb Space Telescope. Both these telescopes are specialized for infrared light. But Webb is far more powerful and considered as a beast in comparison with Spitzer due to Webb’s giant gold-coated beryllium mirror and nine new technologies.
” We have a lot of new questions to ask about the universe because of Spitzer,” said Michael Werner, Spitzer project scientist based at NASA’s Jet Propulsion Laboratory in Pasadena, California. “It’s very gratifying to know there’s such a powerful set of capabilities coming along to follow up on what we’ve been able to start with Spitzer.”
“Having a huge telescope in space is hard. But having a huge telescope that’s cold is much harder,” said Amber Straughn, deputy project scientist for James Webb Space Telescope Science Communications. “Spitzer helped us learn how to better operate a very cold telescope in space.”
Overall, we can say that the James Webb Space Telescope is best of its kind and it’s going to alter our entire understanding of the universe to the core.
-Saifudheen
Credits: NASA,Wikipedia
READ MORE: “Spitzer reveals the Precise timing of a black hole dance“
Author
