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Space Photos of the Week: Tune Into Neptune

Voyager 2 completed its historic flyby 30 years ago. No probe has been back since.
crescent of Neptune's south pole
We're looking at Neptune’s south pole, just barely illuminated by the sun. Voyager 2 took this photo from 560,000 miles away, and even at that extreme distance, the camera on the spacecraft managed to pick up features in the atmosphere as small as 75 miles in diameter. One example: Look on the lower left at the edge of the curve, where you can see a bright white strip of clouds that appears to stretch upward into the shadow.JPL

Thirty years ago NASA’s Voyager 2 spacecraft flew past Neptune, completing its epic journey through the outer solar system. The eighth and outermost planet in our neighborhood, Neptune is considered one of the ice giants, along with Uranus. But that name is a misnomer since the planet is actually covered in gas, and whatever ice is below that is basically slushy.

When Voyager launched we had no idea what Uranus and Neptune looked like up close. The mission uncovered two worlds very unlike any other planets in our solar system, and we now know that both have rings, as well as robust storms and bizarre icy moons. And as scientists discover more exoplanets around other stars, many of them end up looking an awful lot like Neptune—which means that the Voyager 2 planetary data from long ago turns out to be a good model for other planets we might discover in the future.

Did you know Neptune has rings? Most large planets do. Voyager 2 snapped this photo in 1989 during its flyby, and this was the first photo of said rings in detail. Like those surrounding Jupiter and Uranus. Neptune's rings are likely made out of carbon-containing molecules that have been irradiated by the Sun and become darker as a result.NASA/JPL
As Voyager flew by Neptune it kept turning its camera, capturing this beautiful image of a shadowed, crescent Neptune along with its moon Triton. Triton is dwarfed by the sheer size of Neptune, and the darkness of space around them and their shadow feels like a fitting ending to Voyager 2’s journey.NASA/JPL
Triton from 25,000 miles away: This moon is one of the most interesting in the entire solar system. It’s covered with a snakeskin-textured terrain and even has dust devil-like plumes of nitrogen ice jutting out into space. Something else strange is happening on this desolate moon; the surface is pocked with circular depressions that don’t exist anywhere else in the solar system. Scientists suspect that the frozen substances on the surface could be sinking into the ground or melting away, but until we swing by there again, there’s no way to know for sure.NASA/JPL
This image combines red and green filters on Voyager 2’s narrow angle camera to show off the true blue of Neptune’s rich atmosphere, composed mostly of helium, hydrogen, and methane. The methane in the upper atmosphere is responsible for absorbing all the red light from the Sun, which is why Neptune is such a deep azure. The winds in that atmosphere can move at speeds of 1,000 miles per hour, though, which keeps things mixed up: The dark oval storm in the north has since disappeared, and this is the only time it has been captured in a photo with the smaller storm below, nicknamed “Skeeter.”JPL
The ultramarine blue planet almost glows from 4.4 million miles away. While Voyager 2’s mission to Neptune brought the astronomical community a whole new perspective on a far-off planet, it also introduced scientists to many more mysteries, which might not be solved for many decades.NASA/JPL

Want more pretty aqua orbs? Gaze upon WIRED’s full collection of space photos here.

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