https://www.space.com/james-webb-space-telescope-first-year-in-space
Just one year after launch, the James Webb Space Telescope is exceeding all expectations, and astronomers are thrilled.
Launched on Dec. 25, 2021, the $10 billion infrared observatory was designed to learn how galaxies form and grow, to peer far back into the universe to the era of the first galaxies, to watch stars be born inside their nebulous embryos in unprecedented detail, and to probe the atmospheres of exoplanets and characterize some of the closest rocky worlds.
However, the complexity of the James Webb Space Telescope (Webb or JWST), including its fold-out, segmented 21-foot (6.5 meters) mirror and its delicate sun-shield the size of a tennis court, meant that astronomers were on tenterhooks as to whether the JWST would perform as hoped.
It turns out, they needn't have worried. "I guess we really weren't expecting the results to be this good," Brenda Frye, an astronomy at Steward Observatory at the University of Arizona, told Space.com.
The James Webb Space Telescope launched atop an Ariane 5 rocket from French Guiana on Dec. 25, 2021.(Image credit: NASA/Bill Ingalls)
"It's amazing," Steve Longmore, an astrophysicist at Liverpool John Moores University in the U.K., told Space.com. "It's delivering at least as well, and better in a lot of circumstances, than what we were expecting."
And if it exceeds its own targets, it definitely surpasses those of its predecessors. "It's leaps and bounds better than what we've been able to see before," Susan Mullally, JWST's deputy project scientist from the Space Telescope Science Institute (STScI) in Maryland, which operates the observatory, told Space.com, adding that she is "blown away by the imagery, honestly. The images are beautiful."
The main reason that JWST is performing so well is because of its superlative optics, which are able to achieve their maximum potential resolution for the majority of infrared wavelengths that the telescope observes in. This success means that JWST's images have a clarity to them that were unobtainable by the likes of the Hubble Space Telescope and NASA's retired Spitzer Space Telescope, or larger telescopes on the ground such as those at the Keck Observatory in Hawaii, whose vision is blurred by Earth's atmosphere.
But with JWST, individual stars so close together they were once indistinguishable can now be resolved; the structures of very distant galaxies are now discernible; and even something close by such as the rings of Neptune pop with the most detail seen in decades.
The James Webb Space Telescope's stunning view of Neptune, with its rings clearly visible.(Image credit: NASA/ESA/CSA/STScI)
"When the JWST's images of Neptune first came out, both Heidi [Hammel, an interdisciplinary scientist on JWST and an expert on the outer planets of the solar system] and myself looked at them, and then at each other, and asked, 'are we really looking at Neptune'?" Naomi Rowe-Gurney, an astronomer at NASA Goddard Space Flight Center in Maryland, told Space.com.
Although the Keck Observatory has imaged Neptune's rings, our most impressive view before JWST came from Voyager 2's flyby in 1989. "Heidi had not seen the rings [this well] since Voyager 2, and I had never seen the rings like this because Voyager was before I was born!" Rowe-Gurney said.
Normally, faint details or features around a bright object, such as the dark and tenuous rings around blue Neptune, are difficult to see against the glare of the bright object. To counteract this, an instrument is required to have the characteristic of "high dynamic range" to take in both the faint and the bright at the same time.
"We didn't realize that JWST would have this amazing dynamic range and be able to resolve really faint things like the rings of Neptune and the small moons and rings of Jupiter," Rowe-Gurney said.