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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.

Uranus and Neptune: The Big Picture

To understand what’s happening let’s look at what we know about Uranus and Neptune. They’re called “ice giants” because their cores have high proportions of oxygen, carbon, nitrogen, and sulfur. Those elements are called “ices” because they are volatile chemical compounds that freeze right around 100 K. However, the clue to the different colors lies in the planets’ atmospheres. Each has hydrogen, helium, and methane as its main components. These blankets of gases are where each planet’s “weather” occurs. It turns out you need a lot of observations—both visually and in other wavelengths of light—over long periods of time to watch weather play out on these two worlds.

Voyager gave astronomers a taste of what’s “out there”. That led to more long-term observations using other ground-based and space-based observatories. Those studies reveal details about the weather at those worlds and what it does specifically to turn Uranus so pale.

Concentrated Hazes on Uranus and Neptune

Why so blue on Neptune and not so blue on Uranus? As the headline says: hazes. But, scientists needed to explain the existence and activity of hazes in the upper atmospheres of ice giant planets. So, they created a model. The work was done by a team led by Patrick Irwin, Professor of Planetary Physics at Oxford University in England.

Their model actually uses observations of multiple atmospheric layers on Uranus and Neptune. “This is the first model to simultaneously fit observations of reflected sunlight from ultraviolet to near-infrared wavelengths,” explained Irwin in a press release statement. He is the lead author of a paper presenting the team’s model in an upcoming issue of the Journal of Geophysical Research: Planets. “It’s also the first to explain the difference in visible color between Uranus and Neptune.”

Irwin’s team analyzed a set of observations of both planets in ultraviolet, visible, and near-infrared wavelengths (from 0.3 to 2.5 micrometers). The data came from the Near-Infrared Integral Field Spectrometer (NIFS) on the Gemini North telescope (part of the NOIRLab) as well as archival data from the NASA Infrared Telescope Facility. Images and data from the NASA/ESA Hubble Space Telescope also contributed to the study. Together the data revealed surprising structure and activity in both atmospheres.

Inside Blue Planet Atmospheres

The resulting model reveals striking differences between two worlds that otherwise look fairly similar. If we look at each planet in visible light, of course, we see the different shades of blue. The infrared and other data go deeper and reveal details about haze layers. The team’s model shows three layers of aerosols at different heights in the atmosphere. The layer that affects the colors is the middle layer, which is thick with haze particles and is called the Aerosol-2 layer. Both planets have that layer, but it’s the one that appears thicker on Uranus than on Neptune.

The Cause and Effect of Hazes on Uranus and Neptune

This diagram shows three layers of aerosols in the atmospheres of Uranus and Neptune, as modeled by a team of scientists led by Patrick Irwin. The height scale on the diagram represents the pressure above 10 bar. The deepest layer (the Aerosol-1 layer) is thick and composed of a mixture of hydrogen sulfide ice and particles produced by the interaction of the planets’ atmospheres with sunlight.  The key layer that affects the colors is the middle layer, which is a layer of haze particles (referred to in the paper as the Aerosol-2 layer) that is thicker on Uranus than on Neptune. Above both of these layers is an extended layer of haze (the Aerosol-3 layer) similar to the layer below it but more tenuous. On Neptune, large methane ice particles also form above this layer. Courtesy International Gemini Observatory/NOIRLab/NSF/AURA, J. da Silva/NASA /JPL-Caltech /B. JónssonDid you miss our previous article…
https://www.mansbrand.com/compare-sand-dunes-across-the-solar-system-from-venus-to-pluto/

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Review: Mountain Hardwear Kor Airshell Hoody

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10 hours ago

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June 8, 2023

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Ultralight Wind Shell
Mountain Hardwear Kor Airshell Hoody

$150, 5.1 oz./145g (men’s medium)

Sizes: men’s S-XXL, women’s XS-XL

backcountry.com

After sweating hard on a sunny and humid June morning hiking up the headwall of Huntington Ravine—the steepest and hardest trail on Mount Washington—we hit the cool wind blowing across the mountain’s alpine terrain. I pulled on my Kor Airshell Hoody and it tamed that wind while breathing so well that the wet sun shirt against my skin dried out quickly. And that pattern of sweating and hitting wind kept repeating itself on that two-day, 21-mile hut trek in New Hampshire’s Presidential Range, providing plenty of opportunities for the Kor to show off its strengths.

This jacket also displayed excellent breathability when I wore it running hilly trails from the Boise Foothills to central Massachusetts, on spring days of cool wind and temps in the 50s and low 60s Fahrenheit—with me sweating hard on each occasion, but the jacket only getting slightly damp inside and drying in minutes when my exertion level dropped going downhill. I also tested this hoody mountain biking in breezy, partly sunny, 50-degree conditions; and during cool, windy periods while backpacking in the first week of April on a section of the Arizona Trail along the Gila River and in Arizona’s Aravaipa Canyon.

Wind4 016 9
Hi, I’m Michael Lanza, creator of The Big Outside. Click here to sign up for my FREE email newsletter. Join The Big Outside to get full access to all of my blog’s stories. Click here for my e-guides to classic backpacking trips. Click here to learn how I can help you plan your next trip.

The Mountain Hardwear Kor Airshell Hoody.
” data-image-caption=”Testing the Mountain Hardwear Kor Airshell Hoody in New Hampshire’s Presidential Range.
” data-medium-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/06/Mountain-Hardwear-Kor-Airshell-Hoody-with-hood-down-scaled.jpg?fit=300%2C200&ssl=1″ data-large-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/06/Mountain-Hardwear-Kor-Airshell-Hoody-with-hood-down-scaled.jpg?fit=900%2C600&ssl=1″ decoding=”async” width=”900″ height=”600″ src=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/06/Mountain-Hardwear-Kor-Airshell-Hoody-with-hood-down.jpg?resize=900%2C600&ssl=1″ alt=”The Mountain Hardwear Kor Airshell Hoody.” class=”wp-image-58993″ srcset=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/06/Mountain-Hardwear-Kor-Airshell-Hoody-with-hood-down-scaled.jpg?resize=1024%2C683&ssl=1 1024w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/06/Mountain-Hardwear-Kor-Airshell-Hoody-with-hood-down-scaled.jpg?resize=300%2C200&ssl=1 300w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/06/Mountain-Hardwear-Kor-Airshell-Hoody-with-hood-down-scaled.jpg?resize=768%2C512&ssl=1 768w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/06/Mountain-Hardwear-Kor-Airshell-Hoody-with-hood-down-scaled.jpg?resize=1536%2C1024&ssl=1 1536w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/06/Mountain-Hardwear-Kor-Airshell-Hoody-with-hood-down-scaled.jpg?resize=2048%2C1365&ssl=1 2048w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/06/Mountain-Hardwear-Kor-Airshell-Hoody-with-hood-down-scaled.jpg?resize=150%2C100&ssl=1 150w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/06/Mountain-Hardwear-Kor-Airshell-Hoody-with-hood-down-scaled.jpg?w=1800&ssl=1 1800w” sizes=”(max-width: 900px)
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https://mansbrand.com/phew-californias-largest-reservoir-is-nearly-full/

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Phew, California’s Largest Reservoir is Nearly Full

Published

12 hours ago

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June 8, 2023

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California residents will be glad to know their reservoirs are nearly full again after years of drought. New satellite photos show the levels of Shasta Lake, California’s largest reservoir, going from 31% capacity last November to nearly 100% in May 2023. The reservoir was filled with heavy rains and a significant mountain snowpack that melted into the nearby rivers.

This is the highest levels this lake has seen in over four years, following years of persistent and extreme drought in the US southwest. Scientists are working on ways to recharge ground reservoirs with any excess water, to minimize the effect of the next inevitable drought.

Shasta Lake is the eighth largest human-made reservoir in the United States. It has 587 km (365 miles) of mostly mountainous shoreline, with a maximum depth of 157 meters (517 feet.) Lake Mead in Nevada is the largest reservoir in the US.

Here’s a comparison image of Shasta Lake from just a few months ago, November 18, 2022. The tan “bathtub ring” around the perimeter of the lake shows where water had been in previous years.

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A much smaller Shasta Lake, as seen on as seen on November 18, 2022 by the Operational Land Imager (OLI) on the Landsat 8 satellite. Credit: US Geological Survey/NASA Earth Observatory/Lauren Dauphin.

By May 29, it was 98% full, according to California Department of Water Resources (DWR), and the brown ring had disappeared.

Shasta Lake was created in 1948 by the Shasta Dam. Planning for the dam started in 1919 and it was built in the years between 1935 to 1945. Its main purpose is for flood control, water storage for agricultural operations, and hydroelectric generation.

Lake Oroville, the state’s second-largest reservoir, was also near capacity on May 29, at 97% full.

NASA cautions that full reservoirs do not ensure plentiful water for years into the future. Additionally, the increased water levels currently seen in the reservoirs does not necessarily equate to replenished groundwater stores, which is of great concern to the state of California.

“The past four years are a testament to how drastically reservoirs can change over the course of one or two years,” said NASA Earth Observatory’s Lindsey Doermann. “In addition to the many demands for water, lake levels need to be drawn down to create capacity for flood control in wetter seasons. The California DWR is collaborating with other agencies to incorporate better forecasting and observation technologies in order to optimize water releases.”

California enacted a law about 10 years ago to try to protect groundwater reserves from overpumping for agricultural needs. The Sustainable Groundwater Management Act requires local groundwater agencies to halt long-term depletion and achieve sustainability, according to an article on Cal Matters, a state news website. But the deadlines are almost 20 years away, and basins are still being stressed. Groundwater may account for two-thirds of agricultural water use during drought years.

“Just one wet year is nowhere near large enough to refill the amount of groundwater storage that we’ve lost, say, over the last 10 years or more,” said Jeanine Jones, a drought manager with the California DWR, in the Cal Matters article.

A recent study using data from NASA’s Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On satellite missions found that groundwater depletion in the Central Valley has been accelerating since 2003.

NASA said that officials in California are working to leverage the recent influx of water. While some groundwater recharge happens naturally, resource managers can employ other strategies to send water underground, such as diverting it into canals or ponds and injecting it into the subsurface.

The post Phew, California’s Largest Reservoir is Nearly Full appeared first on Universe Today.

Did you miss our previous article…
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NASA’s Europa Clipper Taking “Message in a Bottle” to Jupiter

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13 hours ago

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June 8, 2023

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Laurence Tognetti 600

NASA believes in getting the public excited about space, and they’re carrying on this tradition by recently announcing that space fans from around the world can travel to Jupiter with the Europa Clipper mission. Though, not literally, but by adding their names to a microchip for the “Message in a Bottle” campaign that will also contain “In Praise of Mystery: A Poem for Europa”, which is an original poem by U.S. Poet Laureate Ada Limón.

Participants are encouraged to visit the Europa Clipper “Message in a Bottle” website, where they’re invited to listen to an audio reading of the poem narrated by Limón, and by clicking her name at the bottom of the poem they can watch an animated video of the narrated reading.

Upon submitting their name and email address, the participant will receive an image of their name on a piece of string-tied, rolled paper in a corked glass bottle with Europa’s icy surface in the foreground and the massive Jupiter with a glistening Europa Clipper spacecraft in the background. Participants can then download the image for free directly or via the email they receive and share with their family and friends!

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Example of a participant’s name being sent to Europa with NASA’s “Message in a Bottle” campaign. (Credit: NASA)

“‘Message in a Bottle’ is the perfect convergence of science, art, and technology, and we are excited to share with the world the opportunity to be a part of Europa Clipper’s journey,” Dr. Nicola Fox, who is the associate administrator for NASA’s Science Mission Directorate in Washington DC, said in the announcement. “I just love the thought that our names will be traveling across our solar system aboard the radiation-tolerant spacecraft that seeks to unlock the secrets of Jupiter’s frozen moon.”

Born in Sonoma, California, Ada Limón is an award-winning author of Mexican descent, with her most notable works being “The Carrying”, which was awarded the National Book Critics Circle Award, and “The Hurting Kind”, which was shortlisted for the Griffin Poetry Prize. In 2022, Limón was designated 24th Poet Laureate Consultant in Poetry by Librarian of Congress Carla Hayden, making her the first Latina to be named a U.S. Poet Laureate, and subsequently reappointed to an additional two-year term in 2023. Limón had the privilege of visiting JPL in January 2023 to both see the Europa Clipper spacecraft up-close and learn more about its amazing mission to the icy world.

The Europa Clipper “Message in a Bottle” campaign builds off past NASA campaigns that involve sending names or other tokens of Earth on deep space missions. The most notable campaign is the Golden Record of the Voyager missions that was an elaborate effort encompassing a plethora of individuals, disciplines, and institutions.

In the end, two records were made with each containing 115 images, plus music, sounds, and greetings in several current and ancient languages of Earth with each record sitting on the Voyager 1 and 2 spacecraft in hopes of an extraterrestrial civilization finding them one day. In preparation for the records being found, the scientists include a cartridge and stylus and instructions on how the records could be played.

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The Voyager Golden Record. (Credit: NASA)

Most recently, the NASA Artemis I mission allowed participants to add their names to a flash drive that traveled with the mission around the Moon and back, and NASA’s Perseverance rover mission allowed participants to send their name on a microchip placed on the rover.

The overarching goal of all these campaigns, from the Golden Record to Europa
Did you miss our previous article…
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