The next frontier in space exploration is about to begin.
NASA’s James Webb Space Telescope (JWST) is getting ready to launch, peering at the cosmos with a massive segmented mirror that stretches across 21 feet. With its large, beehive-shaped mirror, James Webb will be able to directly observe a part of space and time that astronomers have never seen before.
The telescope has a few high-priority targets on its list, ranging from distant galaxies from near the universe's infancy to asteroids hovering around the largest planet of the Solar System.
Cristina Thomas, a researcher at the Planetary Science Institute at NASA’s Goddard Space Flight Center, hopes to learn the other side of the universe’s story with the launch of JWST.
“James Webb is going to bring us to this entirely other side of the electromagnetic spectrum, really, to see all of these wavelengths that we just can't see from the ground in incredible detail,” Thomas tells Inverse.
Here are a few of the subjects that Webb will observe in great detail.
5. The Trojan Asteroids
The Trojan asteroids are two groups of rocky bodies that lead and follow Jupiter, and they may have been accompanying the giant planet for the past four billion years.
Although they know very little about the Trojans, scientists believe that they may have been dragged from all over the outer Solar System during its early history billions of years ago and have been trapped in these stable positions ever since, according to NASA.
However, the Trojans are difficult to observe due to their distance and their low albedo, or ability to reflect light.
Jonathan Lunine, chair of the Department of Astronomy at Cornell University, hopes that Webb will be able to provide information on where the asteroids came from and what role they played in Jupiter’s formation.
“There’s the opportunity potentially to get spectra of a number of those objects,” Lunine tells Inverse. “Particularly to see whether the ones that are in the front and the ones that are in the back, the Greeks and the Romans I guess, have some differences in composition that might show up at wavelengths that really have not been applied to those objects before.”
The Trojan asteroids have special features observable in the wavelength that JWST will capture.
“When we look at the ground-based observations, the wavelengths that we can see from the ground are very ambiguous,” Thomas says. “Their sector has very specific signatures because they’re not connected very well to composition.”
Scientists are hoping to learn about the Trojans, where they came from and how they originally formed. The telescope will be able to work with the upcoming Lucy mission to unlock their secrets.
4. The ice moons: Enceladus, Europa, and Titan
Finding habitability in the Solar System is not just confined to planets like Mars, but extends to the most unlikely bodies. The outer Solar System’s icy moons may have the potential for habitability, opening the door to life.
Saturn’s moon Enceladus has a subsurface ocean and plumes of water ice and vapor erupting from the moon’s south polar region, making it one of the most promising places for life in the Solar System.
Its larger counterpart Titan also has the potential for life, possibly harbored in its methane lakes or a liquid water ocean deep below its surface. Meanwhile, Jupiter’s moon Europa has a vast ocean of liquid water, twice as large as the oceans on Earth.
“Webb’s observations of those objects are really more in the area of understanding those bodies as planetary objects,” Lunine says.
JWST will investigate the plumes of Europa and Enceladus, and their icy surfaces.
“With Europa and Enceladus, we’re very aware now that there’s under surface oceans, but what’s in that ocean?” Thomas says. “That changes a lot about the composition and how we understand whether or not those feed into the building blocks of life.”
3. Near-Earth asteroids
There are two main reasons to observe Near-Earth Objects (NEO); the first is to learn about the formation of the Solar System, while the second is to defend Earth against potential impacts by these large objects.
“I’m really excited about the possibilities that open up here,” Thomas says. “We have various different things, from the objects that are close to Earth, and all the way out to the Kuiper Belt objects.”
The Kuiper Belt is the same region of the Solar System that contains Pluto. Planetary scientists believe the Belt contains the leftover remains of the Solar System’s early formation.
“We expect to see that the asteroids are going to look very different than the Kuiper belt objects, and there’s going to be a lot of really interesting comparison science here,” Thomas says.
Scientists have only observed a couple of objects from the Kuiper belt, including Pluto.
“It’s been possible to do observations of large Kuiper belt objects from Earth and by the Hubble telescope,” Lunine says. “But the Earth’s atmosphere gets in the way of many wavelengths that are of interest, and Hubble has limited range in the near-infrared.”
Webb will observe these objects in the near-infrared and cover the wavelengths absorbed by Earth’s atmosphere.
Since discovering the first confirmed exoplanet in 1992, astronomers have observed more than 4,000 alien worlds around distant stars.
A large number of exoplanet discoveries is due in large part to NASA’s Kepler mission and the Transiting Exoplanet Survey Satellite (TESS) missions. But now, scientists will be able to get a closer look at these worlds.
JWST will study the atmosphere of exoplanets in greater detail than those missions and probe whether or not they contain the ingredients necessary for life. It will have a high enough resolution to witness planets passing in front of their home star and draw out atmospheric properties when they transit.
“We have a much larger mirror which means that we can see much fainter things,” Thomas says. “There’s a coronagraph on JWST that will be able to block the light from a central star so that you can actually try to probe a planet directly, which I think will be really exciting.”
One planet that JWST will directly observe is TRAPPIST-1e.
The exoplanet is located only 40 light years away from Earth, and is around the same size as our planet. TRAPPIST-1e also orbits within its star’s habitable zone, which is not too far nor too close for liquid water to exist on its surface.
JWST is planning for five transit observations of TRAPPIST-1e.
“[JWST] is looking for evidence of those atmospheres and looking at surface composition as these planets pass behind their stars,” Lunine says. “So, it could be a real tour de force for the mapping of the atmospheres, and in some cases even the surfaces, of these planets around other stars.”
1. Distant galaxies
The Webb telescope will also be able to peer back in time, observing distant galaxies that have been nearly shielded by their distance.
“Space is expanding, and it’s carrying the cluster of galaxies with it,” Lunine says.
As the universe expands, the further away a galaxy is, the faster it moves away from our view. The faster an object is moving away from us, the more light from that object shifts towards the red part of the spectrum.
“For the most distant galaxies that have been observed, that shift to the red is so large that in the case of Hubble, those galaxies have been shifted to wavelengths that are really at the far end of the red where Hubble can look and even beyond that,” Lunine says.
On the other hand, JWST has infrared capabilities that will look deeper at galaxies that are moving away from our view. The further away scientists can observe, the earlier in the timeline of the universe since light travels at a finite speed further back in time.
Seeing that far back in time allows scientists to better understand how the first galaxies came to be and how they evolved.
“If you were an alien who came to Earth and showed up at a convention of scientists, you probably wouldn’t see many babies there,” Lunine says. “So you would wonder what these creatures actually looked like when they were first born, and that would be an interesting question.”
“We would like that same information for galaxies,” he adds.
As the telescope gets ready for launch, anticipation is high for the images and data that Webb will beam down to Earth.
“I am very excited and very much looking forward to the things that we’re not going to expect,” Thomas says. “There have been so many great discoveries from various missions that NASA has been involved with over the years, and sometimes the greatest thing is that picture that totally blows your mind that is just completely unexpected.”
“And so the thing that I’m really looking forward to is, what is that going to be?”