Neptune and Uranus are so similar that scientists sometimes refer to the distant, icy planets as planetary twins. But these ice giants have one big difference: their color.
“We would expect temperatures to be slowly growing warmer, not colder.”
The ice giants Uranus and Neptune don’t get nearly enough press; all the attention goes to their larger siblings, mighty Jupiter and magnificent Saturn.
Even by the wild standards of the outer solar system, the strange orbits that carry Neptune’s two innermost moons are unprecedented, according to newly published research.
In 2018, astronomers using the NASA/ESA Hubble Space Telescope spotted a giant dark storm, which is 7,400 km (4,600 miles) across, in the northern hemisphere of Neptune. Observations a year later showed that the vortex began drifting southward toward the equator, where such storms are expected to vanish from sight. To the surprise of astronomers, Hubble spotted the vortex change direction by August 2020, doubling back to the north. At the same time as the spot’s stunning reversal, a new, slightly smaller dark feature appeared near its bigger cousin and later disappeared.
Bobbing up and down like a carousel horse might not sound like a stable way to orbit a planet, but it works for one little moon of Neptune. The planet’s innermost known satellite, Naiad, has a tilted orbit and it moves up-and-down relative to its neighboring moon, Thalassa.
A faint and frigid little moon doesn’t have to go by “Neptune XIV” anymore.
It’s both solid and liquid, it’s 60 times denser than ordinary water ice, and it forms at temperatures almost as hot as the sun’s surface.
A dark storm on Neptune, once big enough to reach from Boston to Portugal, is dwindling to nothing as the Hubble Space Telescope keeps watch.
A pioneering new study uncovering the ‘primitive atmosphere’ surrounding a distant world could provide a pivotal breakthrough in the search to how planets form and develop in far-flung galaxies.
