Neptune’s Temperature is Behaving Strangely

One of the great things about science is that it builds on itself over time.  Data collected decades ago is still valid and helps scientists spot trends that would otherwise be lost in the flurry of new data they are trying to collect.  And sometimes, that data holds something interesting.  Such is the case when a group of scientists took a look at the infrared data of Neptune’s atmosphere and found not one but two weird changes happening.

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Why do Uranus and Neptune Have Magnetic Fields? Hot ice

The outer “ice giant” planets, Neptune and Uranus, have plenty of mysteries.  One of the biggest is where exactly they got their magnetic fields.  They are strong at that, with Neptune’s being twenty-seven times more powerful than Earth’s, while Uranus’ varies between ?  and four times Earth’s strength.  Chaos rules in these electromagnetic environments, making them exceptionally hard to both understand and model.  Now a team of researchers led by Dr. Vitali Prakpenka of the University of Chicago thinks they might have found the underlying cause of both the field’s strength and its randomness – “hot ice.”

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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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Hubble Releases a New Image of Neptune, Revealing a Rapidly Shifting Storm

This Hubble Space Telescope snapshot of the dynamic blue-green planet Neptune reveals a monstrous dark storm [top center] and the emergence of a smaller dark spot nearby [top right]. CREDITS: NASA, ESA, STScI, M.H. Wong (University of California, Berkeley) and L.A. Sromovsky and P.M. Fry (University of Wisconsin-Madison)

Storms on Neptune seem to follow a pattern of forming, strengthening and then dissipating over the course of about two Earth years. But a Neptunian storm spotted in the planet’s atmosphere over two years ago has done something quite different: it has reversed course and is still going strong.

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Neptune & Triton – August 31, 1989.

Processed using calibrated orange, green, and blue filtered images of Neptune and Triton taken by Voyager 2 on August 31 1989. Image Credit: NASA/JPL-Caltech/Kevin M. Gill

Image-processor extraordinaire Kevin Gill has reached back in time to give us a new image of Neptune and its moon Triton.

When NASA’s Voyager 2 spacecraft flew past Neptune and Triton in August 1989, its cameras were very busy. Kevin has taken separate color-filtered images from that visit and calibrated and combined them to give us a new, almost haunting look at the planet and its largest moon.

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NASA Thinks it’s Time to Return to Neptune With its Trident Mission

Artist's impression of what the surface of Triton may look like. Credit: ESO

Is it time to head back to Neptune and its moon Triton? It might be. After all, we have some unfinished business there.

It’s been 30 years since NASA’s Voyager 2 spacecraft flew past the gas giant and its largest moon, and that flyby posed more questions than it answered. Maybe we’ll get some answers in 2038, when the positions of Jupiter, Neptune, and Triton will be just right for a mission.

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Two of Neptune’s Moons Dance Around Each Other as they Orbit

Neptune's moons Naiad and Thalassa are locked in a lunar dance. Image Credit: NASA/JPL

Like a long-married couple accustomed to each other’s kitchen habits, two of Neptune’s moons are masters at sharing space without colliding. And though both situations may appear odd to an observer, there’s a certain dance-like quality to them both.

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Say Hello to Hippocamp! The New Moon Discovered at Neptune, Which Could Have Broken off from the Larger Moon Proteus

An artist's illustration of the tiny Neptunian moon Hippocamp. Image Credit: NASA, ESA and J. Olmsted (STScI)
An artist's illustration of the tiny Neptunian moon Hippocamp. Image Credit: NASA, ESA and J. Olmsted (STScI)

Moons have the coolest names, don’t they? Proteus, Titan, and Callisto. Phobos, Deimos, and Encephalitis. But not Io. That’s a stupid name for a moon. There’s only two ways to pronounce it and we still get it wrong. Anyway, now we have another cool one: Hippocamp!

Okay, maybe the new name isn’t that cool. It sounds like a summer camp for overweight artiodactyls. But whatever. It’s not every day our Solar System gets a new moon.

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Exploring the Ice Giants: Neptune and Uranus at Opposition for 2018

Neptune, as seen by Voyager 2 in 1989. The deep blue color applied helped enhance the view of features in the atmosphere. Image Credit: NASA/JPL
Neptune, as seen by Voyager 2 in 1989. The deep blue color applied helped enhance the view of features in the atmosphere. Image Credit: NASA/JPL

Have you seen the outer ice giant planets for yourself?

This week is a good time to check the most difficult of the major planets off of your life list, as Neptune reaches opposition for 2018 on Friday, September 7th at at ~18:00 Universal Time (UT)/2:00 PM EDT. And while it may not look like much more than a gray-blue dot at the eyepiece, the outermost ice giant world has a fascinating tale to tell. Continue reading “Exploring the Ice Giants: Neptune and Uranus at Opposition for 2018”

Neptune’s Huge Storm Is Shrinking Away In New Images From Hubble

Jupiter's prominent storm, the Great Red Spot, is held in place by the alternating storm bands in Jupiter's atmosphere. Image: By NASA, ESA, and A. Simon (Goddard Space Flight Center) [Public domain], via Wikimedia Commons

Back in the late 1980’s, Voyager 2 was the first spacecraft to capture images of the giant storms in Neptune’s atmosphere. Before then, little was known about the deep winds cycling through Neptune’s atmosphere. But Hubble has been turning its sharp eye towards Neptune over the years to study these storms, and over the past couple of years, it’s watched one enormous storm petering out of existence.

“It looks like we’re capturing the demise of this dark vortex, and it’s different from what well-known studies led us to expect.” – Michael H. Wong, University of California at Berkeley.

When we think of storms on the other planets in our Solar System, we automatically think of Jupiter. Jupiter’s Great Red Spot is a fixture in our Solar System, and has lasted 200 years or more. But the storms on Neptune are different: they’re transient.

Voyager 2 captured this image of Neptune in 1982, when it was over 7 million km (4.4 million miles) away from the planet. The Great Dark Spot in the middle of the image was the first storm ever seen on Neptune. Image: By NASA (JPL image) [Public domain], via Wikimedia Commons

The storm on Neptune moves in an anti-cyclonic direction, and if it were on Earth, it would span from Boston to Portugal. Neptune has a much deeper atmosphere than Earth—in fact it’s all atmosphere—and this storm brings up material from deep inside. This gives scientists a chance to study the depths of Neptune’s atmosphere without sending a spacecraft there.

The first question facing scientists is ‘What is the storm made of?’ The best candidate is a chemical called hydrogen sulfide (H2S). H2S is a toxic chemical that stinks like rotten eggs. But particles of H2S are not actually dark, they’re reflective. Joshua Tollefson from the University of California at Berkeley, explains: “The particles themselves are still highly reflective; they are just slightly darker than the particles in the surrounding atmosphere.”

“We have no evidence of how these vortices are formed or how fast they rotate.” – Agustín Sánchez-Lavega, University of the Basque Country in Spain.

But beyond guessing what chemical the spot might me made of, scientists don’t know much else. “We have no evidence of how these vortices are formed or how fast they rotate,” said Agustín Sánchez-Lavega from the University of the Basque Country in Spain. “It is most likely that they arise from an instability in the sheared eastward and westward winds.”

There’ve been predictions about how storms on Neptune should behave, based on work done in the past. The expectation was that storms like this would drift toward the equator, then break up in a burst of activity. But this dark storm is on its own path, and is defying expectations.

“We thought that once the vortex got too close to the equator, it would break up and perhaps create a spectacular outburst of cloud activity.” – Michael H. Wong, University of California at Berkeley.

“It looks like we’re capturing the demise of this dark vortex, and it’s different from what well-known studies led us to expect,” said Michael H. Wong of the University of California at Berkeley, referring to work by Ray LeBeau (now at St. Louis University) and Tim Dowling’s team at the University of Louisville. “Their dynamical simulations said that anticyclones under Neptune’s wind shear would probably drift toward the equator. We thought that once the vortex got too close to the equator, it would break up and perhaps create a spectacular outburst of cloud activity.”

Rather than going out in some kind of notable burst of activity, this storm is just fading away. And it’s also not drifting toward the equator as expected, but is making its way toward the south pole. Again, the inevitable comparison is with Jupiter’s Great Red Spot (GRS).

The GRS is held in place by the prominent storm bands in Jupiter’s atmosphere. And those bands move in alternating directions, constraining the movement of the GRS. Neptune doesn’t have those bands, so it’s thought that storms on Neptune would tend to drift to the equator, rather than toward the south pole.

Jupiter’s prominent storm, the Great Red Spot, is held in place by the alternating storm bands in Jupiter’s atmosphere. Image: By NASA, ESA, and A. Simon (Goddard Space Flight Center) [Public domain], via Wikimedia Commons

This isn’t the first time that Hubble has been keeping an eye on Neptune’s storms. The Space Telescope has also looked at storms on Neptune in 1994 and 1996. The video below tells the story of Hubble’s storm watching mission.

The images of Neptune’s storms are from the Hubble Outer Planets Atmosphere Legacy (OPAL) program. OPAL gathers long-term baseline images of the outer planets to help us understand the evolution and atmospheres of the gas giants. Images of Jupiter, Saturn, Uranus and Neptune are being taken with a variety of filters to form a kind of time-lapse database of atmospheric activity on the four gas planets.