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NASA detects unexpected lightning storms in Jupiter's upper atmosphere
Some of the most extreme weather in the Solar System just got stranger.
- The Juno space probe orbiting Jupiter has observed lightning at impossibly high points in the Jovian atmosphere.
- The findings, combined with other atmopsheric data, led to the creation of a new model of the atmosphere.
- The findings answer a few questions about Jupiter, but create many more.
Since 2016, NASA's Juno spacecraft has been observing Jupiter's atmosphere, magnetosphere, and gravitational field. It has already managed to take fantastic images, discovered new cyclones, and analyze the gasses that make up the planet in the time it has spent investigating it.
This week, Juno was able to add another discovery to its name with the unexpected finding of lightning in the upper atmosphere of the Solar System's largest planet.
The findings are described in the study "Small lightning flashes from shallow electrical storms on Jupiter," published in Nature. Previous missions to Jupiter, including Voyager 1, Galileo, and New Horizons all observed lightning, but without the benefits of the equipment on Juno or more recent developments in models of the Jovian atmosphere.
In this case, the lighting is notable for how high it is occurring in the atmosphere. While previous observations suggested lightning in water-based clouds deep inside the gas planet, the new data suggests lightning exists in the upper atmosphere in clouds of water and ammonia. This lightning is dubbed "shallow lightning."
According to a press release by Cornell University, the ammonia is vital in creating the lightning, as it functions as an "anti-freeze" of sorts to keep the water in the clouds from freezing. The collision of droplets of mixed ammonia and water with ice water particles creates the charge needed for lightning strikes.
This is different from any process that creates lightning on Earth.
That wasn't the only bit of strangeness the probe noticed. While Juno saw plenty of ammonia near the equator and at lower levels of the atmosphere, it was hard-pressed to find much anywhere else. To explain this, researchers developed a new model of atmospheric mixing. They suggest that the ammonia at lower levels of the atmosphere rises into storm clouds, interacts with water to cause the aforementioned lightning, and then falls back down in the form of hailstones.
This model explains many things, including why Juno couldn't detect ammonia where it expected to: the mushballs would be more challenging to detect than ammonia or water vapor. The scientists further speculated that the weight of the mushballs pulls the ammonia to lower levels of the atmosphere where it is detected in more significant amounts.
A NASA designed graphic demonstrating the weather systems theorized to create "mushballs." The liquid water and ammonia rises in the storm clouds until they reach points where the extremely low temperatures cause them to freeze. Freezing into semi-solid "mushballs" causes them to fall where they redistribute ammonia throughout the lower atmosphere.
How can we possibly know all of this?
Juno relies on several pieces of equipment. The most relevant in this case is the microwave radiometer. This device uses microwaves to measure the Jovian atmosphere's composition. When microwaves hit water or ammonia particles, they begin to heat up. By hitting the planet with microwaves and then looking for changes in the particles' observed temperature, the probe can determine what chemicals are present.
The findings of these studies demonstrate that Jupiter's atmosphere is more complicated than previously thought. Given how we already knew about the storms larger than Earth, temperatures that swing between extremes in different layers of the atmosphere, and winds that blow at 100 meters per second, that is saying something.
- NASA's Juno Probe Overcame Insane Obstacles to Reach Jupiter ... ›
- Jupiter formation: Scientists discover new origin story - Big Think ›
- Does Lightning Come From Outer Space? - Big Think ›
An open letter predicts that a massive wall of rock is about to plunge into Barry Arm Fjord in Alaska.
- A remote area visited by tourists and cruises, and home to fishing villages, is about to be visited by a devastating tsunami.
- A wall of rock exposed by a receding glacier is about crash into the waters below.
- Glaciers hold such areas together — and when they're gone, bad stuff can be left behind.
The Barry Glacier gives its name to Alaska's Barry Arm Fjord, and a new open letter forecasts trouble ahead.
Thanks to global warming, the glacier has been retreating, so far removing two-thirds of its support for a steep mile-long slope, or scarp, containing perhaps 500 million cubic meters of material. (Think the Hoover Dam times several hundred.) The slope has been moving slowly since 1957, but scientists say it's become an avalanche waiting to happen, maybe within the next year, and likely within 20. When it does come crashing down into the fjord, it could set in motion a frightening tsunami overwhelming the fjord's normally peaceful waters .
The Barry Arm Fjord
Camping on the fjord's Black Sand Beach
Image source: Matt Zimmerman
The Barry Arm Fjord is a stretch of water between the Harriman Fjord and the Port Wills Fjord, located at the northwest corner of the well-known Prince William Sound. It's a beautiful area, home to a few hundred people supporting the local fishing industry, and it's also a popular destination for tourists — its Black Sand Beach is one of Alaska's most scenic — and cruise ships.
Not Alaska’s first watery rodeo, but likely the biggest
Image source: whrc.org
There have been at least two similar events in the state's recent history, though not on such a massive scale. On July 9, 1958, an earthquake nearby caused 40 million cubic yards of rock to suddenly slide 2,000 feet down into Lituya Bay, producing a tsunami whose peak waves reportedly reached 1,720 feet in height. By the time the wall of water reached the mouth of the bay, it was still 75 feet high. At Taan Fjord in 2015, a landslide caused a tsunami that crested at 600 feet. Both of these events thankfully occurred in sparsely populated areas, so few fatalities occurred.
The Barry Arm event will be larger than either of these by far.
"This is an enormous slope — the mass that could fail weighs over a billion tonnes," said geologist Dave Petley, speaking to Earther. "The internal structure of that rock mass, which will determine whether it collapses, is very complex. At the moment we don't know enough about it to be able to forecast its future behavior."
Outside of Alaska, on the west coast of Greenland, a landslide-produced tsunami towered 300 feet high, obliterating a fishing village in its path.
What the letter predicts for Barry Arm Fjord
Moving slowly at first...
Image source: whrc.org
"The effects would be especially severe near where the landslide enters the water at the head of Barry Arm. Additionally, areas of shallow water, or low-lying land near the shore, would be in danger even further from the source. A minor failure may not produce significant impacts beyond the inner parts of the fiord, while a complete failure could be destructive throughout Barry Arm, Harriman Fiord, and parts of Port Wells. Our initial results show complex impacts further from the landslide than Barry Arm, with over 30 foot waves in some distant bays, including Whittier."
The discovery of the impeding landslide began with an observation by the sister of geologist Hig Higman of Ground Truth, an organization in Seldovia, Alaska. Artist Valisa Higman was vacationing in the area and sent her brother some photos of worrying fractures she noticed in the slope, taken while she was on a boat cruising the fjord.
Higman confirmed his sister's hunch via available satellite imagery and, digging deeper, found that between 2009 and 2015 the slope had moved 600 feet downhill, leaving a prominent scar.
Ohio State's Chunli Dai unearthed a connection between the movement and the receding of the Barry Glacier. Comparison of the Barry Arm slope with other similar areas, combined with computer modeling of the possible resulting tsunamis, led to the publication of the group's letter.
While the full group of signatories from 14 organizations and institutions has only been working on the situation for a month, the implications were immediately clear. The signers include experts from Ohio State University, the University of Southern California, and the Anchorage and Fairbanks campuses of the University of Alaska.
Once informed of the open letter's contents, the Alaska's Department of Natural Resources immediately released a warning that "an increasingly likely landslide could generate a wave with devastating effects on fishermen and recreationalists."
How do you prepare for something like this?
Image source: whrc.org
The obvious question is what can be done to prepare for the landslide and tsunami? For one thing, there's more to understand about the upcoming event, and the researchers lay out their plan in the letter:
"To inform and refine hazard mitigation efforts, we would like to pursue several lines of investigation: Detect changes in the slope that might forewarn of a landslide, better understand what could trigger a landslide, and refine tsunami model projections. By mapping the landslide and nearby terrain, both above and below sea level, we can more accurately determine the basic physical dimensions of the landslide. This can be paired with GPS and seismic measurements made over time to see how the slope responds to changes in the glacier and to events like rainstorms and earthquakes. Field and satellite data can support near-real time hazard monitoring, while computer models of landslide and tsunami scenarios can help identify specific places that are most at risk."
In the letter, the authors reached out to those living in and visiting the area, asking, "What specific questions are most important to you?" and "What could be done to reduce the danger to people who want to visit or work in Barry Arm?" They also invited locals to let them know about any changes, including even small rock-falls and landslides.
What makes some people more likely to shiver than others?
Some people just aren't bothered by the cold, no matter how low the temperature dips. And the reason for this may be in a person's genes.
Eating veggies is good for you. Now we can stop debating how much we should eat.
- A massive new study confirms that five servings of fruit and veggies a day can lower the risk of death.
- The maximum benefit is found at two servings of fruit and three of veggies—anything more offers no extra benefit according to the researchers.
- Not all fruits and veggies are equal. Leafy greens are better for you than starchy corn and potatoes.