But those mysteries can wait, at least for a little bit, when you’ve got pictures like these. Nor do they understand the peculiar nature of Neptunian weather and seasons. Scientists don’t know why Neptune radiates more heat than it absorbs from the sun, whereas Uranus, which is similar in composition and orbits closer in, doesn’t. We are much more familiar with Neptune now, although the planet still has its mysteries. In their telescopes, Neptune was a tiny speck of light, as ordinary as any other star in the night sky. Astronomers already suspected that the planet existed they had noticed, more than half a century earlier, some irregularities in Uranus’s orbit that could only be explained by the presence of another celestial body further out. The first direct observations of Neptune were made in 1846. (There will be no Webb views of Venus and Mercury, though Webb’s mirrors are oriented toward deep space and away from the sun, Earth, and other objects in the inner solar system-all bright sources that would fry the observatory’s instruments.) Uranus will eventually get its own close-up too. The observatory has captured a remarkable view of Jupiter and the lustrous auroras drifting over its poles, and snuck a peek at Mars. The new Neptune observations are the first of many for the Webb telescope, which has been making the rounds of the solar system since it began operations this summer. Triton, resembling a shiny, bluish jewel, with its parent planet (NASA, ESA, CSA, and STScI) The Voyager mission detected plumes of nitrogen gas coming from cracks in the frosty surface, and astronomers think that Triton has a subsurface ocean-making the moon an intriguing candidate in the search for microbial alien life. Triton, a world covered in frozen nitrogen, is so reflective that it resembles a star, in Webb’s view. Zoom out further, and you’ll see a bluish jewel that is Triton, Neptune’s largest moon. The tiny specks of light around the planet are moons-seven of them. Those iridescent bright spots on the planet itself? They are clouds made of methane ice. The Webb telescope is far more powerful than Hubble and has not only captured the sharp outlines of the planet’s rings, but resolved the fuzzy bands of dust that hover between them. No spacecraft has visited the planet since Voyager, and space telescopes such as Hubble have already observed the planet about as much as they can. That 33-year-old image was our best view of Neptune’s ring system until now. Voyager’s view of Neptune’s rings (NASA / JPL) Read: A gnarly new theory about Saturn’s rings The evidence for Neptune’s rings came in 1989, when Voyager finally reached that planet and revealed wispy, elegant arcs. (I know, right? Those classic illustrations of the solar system really left a lot out.) Astronomers discovered faint bands around Uranus using ground-based observations in 1977, and NASA’s Voyager mission revealed the same around Jupiter in 1979. After all, Saturn had them, and so, it turned out, did Uranus and Jupiter. Scientists imagined that Neptune might have rings well before they had any evidence. We’ve never seen Neptune and its rings like this before. And already, that promise is being fulfilled. This was part of the promise of the Webb mission: As the telescope searched the depths of the universe for the faintest, earliest galaxies, it would also provide an entirely new view of our cosmic neighborhood. The observatory that produced the image, the James Webb Space Telescope, works in infrared wavelengths, so Neptune resembles a spooky crystal ball dipped in dry ice rather than its usual, striking cobalt-blue self. There they are, a pair of delicate bands encircling a shimmery marble, the whole ensemble doing its best impression of Saturn. So I wanted to present this information to you, and let it sink in a little bit, before getting into the news of the day: Astronomers have directed their best space telescope at Neptune and captured the clearest view of its rings in more than 30 years. But for those of us who have certain textbook images of the solar system in our mind, the knowledge that Neptune is a ringed planet might come as a surprise. Planetary scientists know this, as do hard-core astronomy fans, probably. The planet we’re now told is the farthest from us has a set of narrow bands made of dust.
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