There's a Polar Cyclone on Uranus' North Pole

NASA scientists used microwave observations to spot the first polar cyclone on Uranus, seen here as a light-colored dot to the right of center in each image of the planet. The images use wavelength bands K, Ka, and Q, from left. To highlight cyclone features, a different color map was used for each. Credit: NASA/JPL-Caltech/VLA.

Uranus takes 84 years to orbit the Sun, and so that last time that planet’s north polar region was pointed at Earth, radio telescope technology was in its infancy.

But now, scientists have been using radio telescopes like the Very Large Array (VLA) the past few years as Uranus has slowly revealing more and more of its north pole. VLA microwave observations from 2021 and 2022 show a giant cyclone swirling around this region, with a bright, compact spot centered at Uranus’ pole. Data also reveals patterns in temperature, zonal wind speed and trace gas variations consistent with a polar cyclone.

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Four of Uranus’ Moons Might Have Liquid Oceans, Too

Recent computer models estimate the likelihood of interior oceans in four of Uranus’ major moons: Ariel, Umbriel, Titania, and Oberon, but Miranda is likely too small to sustain enough heat for an interior ocean. (Credit: NASA/JPL-Caltech)

The study of ocean worlds, planetary bodies with potential interior reservoirs of liquid water, has come to the forefront in terms of astrobiology and the search for life beyond Earth. From Jupiter’s Galilean Moons to Saturn’s Titan and Mimas to Neptune’s Triton and even Pluto, scientists are craving to better understand if these worlds truly possess interior bodies of liquid water. But what about Uranus and its more than two dozen moons? Could they harbor interior oceans, as well?

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The Rings of Uranus Shine Bright in Stunning New JWST Image

This zoomed-in image of Uranus, captured by Webb’s Near-Infrared Camera (NIRCam) Feb. 6, 2023, reveals stunning views of the planet’s rings. Credit: NASA, ESA, CSA, STScI IMAGE PROCESSING: Joseph DePasquale (STScI).

The James Webb Space Telescope has taken a stunning new image of the ice giant world Uranus. But what stands out most is the dramatic new view of the planet’s rings, which show up as never before with JWST’s infrared eyes.

Instead of being faint and wispy, the rings show up brilliantly. Additionally, bright, luminous features in the planet’s atmosphere show how an extensive storm system at the north pole of this planet getting larger and brighter.

But you’ll also want to see the full-frame image view, which also shows the six largest of Uranus’ 27 known moons. And, as we’ve become accustomed to seeing in JWST images, several distant background galaxies. Yes, every JWST image is a Deep Field!

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It's Time For Your Annual Weather Update for the Outer Solar System

Jupiter, as seen by the Hubble Space Telescope in November 2022 and January 2023. Credits: NASA, ESA, STScI, Amy Simon (NASA-GSFC), and Michael H. Wong (UC Berkeley); Image Processing: Joseph DePasquale (STScI).

A couple times a year, the Hubble Space Telescope turns its powerful gaze on the giant planets in the outer Solar System, studying their cloudtops and weather systems. With the Outer Planet Atmospheres Legacy (OPAL) Program, Hubble provides us with these views and also delivers weather reports on what’s happening. Here’s an updated report and some new images of the stormy surfaces of Jupiter and Uranus.  

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A Migrating Moon Might Have Turned Uranus Over on its Side

There are plenty of interesting things about Uranus. Its season lasts as long as its day, it’s the second least-dense planet, and it has a collection of 27 moons. But maybe the most puzzling fact about Uranus is that it is the only planet that lines on its side – relative to its orbital plane, at least. The most common suggestion for why the planet is tilted 98 degrees on its axis is that it was struck by a series of large impacts early in the solar system’s formation. However, new studies from a team at the Sorbonne point to a potential alternative explanation – Uranus used to have another, larger moon that pulled it onto its side and then impacted the planet itself.

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Why are Uranus and Neptune Different Colors? Haze

NASA’s Voyager 2 spacecraft captured these views of Uranus (on the left) and Neptune (on the right) during its flybys of the planets in the 1980s.

Way back in the late 1980s, the Voyager 2 spacecraft visited Uranus and Neptune. During the flybys, we got to see the first close-up views of those ice giants. Even then, planetary scientists noticed a marked color difference between the two. Yes, they both sport shades of blue. But, if you look closely at Uranus, you see a featureless pale blue planet. Neptune, on the other hand, boasts interesting clouds, dark banding, and dark spots that come and go. They’re all set against a darker blue backdrop.

So, why the difference? Planetary scientists have long suspected aerosols (droplets of gas that have liquids or dust suspended in them) in each atmosphere. But, according to a team of scientists studying the layers of the planets, the hazes those aerosols create may only be part of the story.

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Giant Balls of Mush Made From Ammonia and Water Form in the Atmospheres of Uranus and Neptune

One advantage to planetary science is that insights from one planet could explain phenomena on another.  We understand Venus’ greenhouse gas effect from our own experience on the Earth, and Jupiter and Saturn share some characteristics.  But Jupiter also provides insight into other, farther out systems, such as Uranus and Neptune.  Now, a discovery from a spacecraft orbiting Jupiter might have solved a long-standing mystery about Uranus and Neptune – where has all the ammonia gone?

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What Mission Could Detect Oceans at Uranus’ Moons?

Exploration of ocean worlds has become a hot topic of late, primarily due to their role as a potential harbor for alien life.  Moons that have confirmed subsurface oceans garner much of the attention, such as Enceladus and Europa.  But they may not be the only ones.  Uranus’ larger moonsMiranda, Ariel, and Umbriel could potentially also have subsurface oceans even farther out into the solar system.  We just haven’t sent any instruments close enough to be able to check.  Now a team led by Dr. Corey Cochrane at NASA’s Jet Propulsion laboratory has done some preliminary work to show that a relatively simple flyby of the Uranian system with an averagely sensitive magnetometer could provide the data needed to determine if those larger moons harbor subsurface oceans.  This work is another step down the path of expanding what we think of as habitable environments in the solar system.

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Uranus X-Rays are Probably Reflected Sunlight, but There Could be Another Source as Well

X-rays offer a unique insight into the astronomical world.  Invisible to the naked eye, most commonly they are thought of as the semi-dangerous source of medical scans.  However, X-ray observatories, like the Chandra X-ray Observatory are capable of seeing astronomical features that no other telescope can.  Recently scientists found some of those X-rays coming from a relatively unexpected source – Uranus.

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Uranus’ Moons are Surprisingly Similar to Dwarf Planets in the Kuiper Belt

Ö. H. Detre et al./MPIA

Astronomer William Herschel discovered Uranus—and two of its moons—230 years ago. Now a group of astronomers working with data from the telescope that bears his name, the Herschel Space Observatory, have made an unexpected discovery. It looks like Uranus’ moons bear a striking similarity to icy dwarf planets.

The Herschel Space Observatory has been retired since 2013. But all of its data is still of interest to researchers. This discovery was a happy accident, resulting from tests on data from the observatory’s camera detector. Uranus is a very bright infrared energy source, and the team was measuring the influence of very bright infrared objects on the camera.

The images of the moons were discovered by accident.

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