James Webb Space Telescope around the corner from deep universe towards our home solar system, and take a picture of luminous Neptune and its fine, dusty rings in detail we haven’t seen in decades.
The last time astronomers got such a clear view of the farthest planet from the sun was when Voyager 2 became the first and only space probe to fly over the ice giant for just a few hours in 1989.
Webb’s unprecedented infrared imaging capability has now provided a new glimpse into Neptune’s atmosphere, said Mark McGreen, ESA’s senior science and exploration adviser.
McCurren, who has worked on the Webb project for more than 20 years, said the telescope is “removing all that glare and background away” so we can “begin to extract the composition of the atmosphere” of the planet.
Neptune appears dark blue in earlier images taken by the Hubble Space Telescope due to methane in its atmosphere.
However, the near-infrared wavelengths captured by the NIRCam primary web imager show the planet as grayish-white, with ice clouds on the surface.
“The rings are more reflective of infrared, so it’s easier to see,” McCogren said.
In a statement, NASA said the image also shows an “interesting brightness” near the top of Neptune. Since the planet tilts away from Earth and takes 164 years to orbit the sun, astronomers haven’t gotten a good look at the North Pole yet.
Webb also discovered seven of Neptune’s 14 known moons. Looming over Neptune in a magnified image is what appears to be a very bright spiky star, but is in fact Triton, Neptune’s strangely massive moon full of famous Webb eccentric halos.
Triton, which is larger than the dwarf planet Pluto, appears brighter than Neptune because it is covered in ice, which reflects light. Meanwhile, McCurren said that Neptune “absorbs most of the light falling on it.”
Since Triton orbits in the wrong direction around Neptune, it is once thought to have been a near Kuiper belt object captured in the planet’s orbit. “So it’s great to go and have a look,” McCurren said.
As astronomers sweep the universe in search of other planets like ours, they find that ice giants like Neptune and Uranus are the most common in the Milky Way. “By being able to look at these things in great detail, we can enter our observations of other ice giants,” McCurren said.
Operating since July, Webb is the most powerful space telescope ever built, and it has already released unprecedentedly abundant data. Scientists hope it heralds a new era of discovery.
The search is expected to take place based on Webb’s observations of Neptune and Triton next year.
“The kind of astronomy we see now was unimaginable five years ago,” McCurren said.
“Of course, we knew he was going to do this, we built it to do it, it’s exactly the machine that we designed. But to suddenly start seeing things at these longer wavelengths, which was impossible before… It’s pretty cool.”