A flickering image of Neptune’s rings is visible from the JWST

As if delicate iridescent fairies race around a cosmic track, Neptune’s rings shimmer in a stunning new view captured by the James Webb Space Telescope (JWST), the most powerful extraterrestrial observatory ever built. It’s the sharpest image of the planet’s rings since Voyager 2’s 1989 flyby, and it reveals a plethora of never-before-seen detail.

“For me, looking at JWST’s new Neptune image is like catching up with a friend you haven’t seen in over 10 years – and he looks great,said Jane Rigby, an astrophysicist at NASA’s Goddard Space Flight Center who is the agency’s JWST project scientist, in an email to American Scientist.

After a thrilling launch on Christmas Day in 2021, the telescope began full operation in July and has since splashed the news with jaw-dropping images of nebulae and discoveries of ancient galaxies that could ‘shatter cosmology’ . But JWST’s piercing infrared eyes also open up new vistas closer to home when they’re focused on the suite of worlds in our solar system.

For example, the telescope view of Neptune shows the planet’s faint dust lanes with unprecedented clarity. These appear as fuzzy particles between the brighter ice-dominated rings, says Mark McCaughrean, senior science adviser at the European Space Agency (ESA) and member of the JWST science working group.

When University of Arizona astronomer Marcia Rieke had the opportunity to observe the new views of Neptune, she said, “As usual, I’m blown away by what we’re seeing.” Rieke, who is currently the principal investigator of JWST’s main imager called the Near Infrared Camera (NIRCam), recalls trying to view Neptune’s rings years ago using a ground-based telescope. on Kitt Peak in Arizona. “We hardly saw anything because of the fineness and clumping of the rings,” she says. “It’s wonderful to see them so clearly and easily [with JWST].”

In this image from JWST’s NIRCam, a handful of hundreds of background galaxies, varying in size and shape, appear alongside the Neptune system. Credit: NASA, ESA, ASC and STScI

Clouds of methane ice appear as bright streaks and blotches in the image, shining in the faint sunlight that reaches Neptune about 2.8 billion miles away. Seven of the planet’s 14 moons are also hidden in the JWST photograph. The brightest is the strange Triton, a large natural satellite covered in nitrogen ice that reflects about 70% of incoming sunlight. While most planetary moons, including all others around Neptune, orbit with the rotation of their planetary host, Triton does so in the opposite direction. This orbit suggests to researchers that the body is likely a migrant from the outer solar system captured long ago by Neptune’s gravity.

“It will be really cool to go measure the spectrum of Triton because it represents a body from further afield,” McCaughrean said.

JWST’s infrared view also shows a thin, glowing band circling the equator, likely produced by hotter gas flowing toward Neptune’s mid-latitudes as part of an increasingly choppy pattern of global atmospheric circulation. According to an ESA press release, such features could drive the planet’s powerful winds and storms.

“What jumps out at me are all the beautiful clouds and storms in Neptune’s atmosphere,” says Nikole Lewis, associate professor of astronomy at Cornell University. “Neptune has the highest measured wind speeds in the solar system, with average wind speeds near [the] equator of 700 miles per hour and maximum wind speeds in places over 1,000 miles per hour. While Lewis’ own work with JWST will focus on planets beyond the solar system, she calls the new image “a stunning snapshot of its turbulent times.”

Unlike Voyager 2, which provided snapshots of Neptune at one point, JWST’s studies of Neptune and other inhabitants of the solar system will continue as long as the observatory itself lasts. By comparing these JWST and future images with those from Voyager 2, scientists hope to learn more about longer-term atmospheric changes on the planet, such as Neptune’s seasons, McCaughrean said. Because the planet is tilted at an angle of 28 degrees along its axis, it experiences four seasons, just like Earth. But on Neptune, each lasts about 40 years due to the long journey of 164 Earth years around the sun. That means the planet has pretty much entered a different season than when Voyager 2 passed, McCaughrean says.

While Neptune may be the crown jewel of the recently released snapshot, the magnified view shows “a bit of the poetic side of planets suspended in space,” McCaughrean says, referring to the background of the images. distant stars and galaxies that seem to surround the icy giant.

Nearly a million miles from Earth and packed with imaging tools, JWST will continue to provide deeper, clearer views of the universe and our place in it. “JWST, even in just a few months, has already started adding that cosmic perspective,” McCaughrean says. “But to be honest, you haven’t seen anything yet.”

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