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Unravelling the mysteries of clouds
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By NASA
Earth (ESD)Earth Home Explore Climate Change Science in Action Multimedia Data For Researchers 4 min read
Via NASA Plane, Scientists Find New Gamma-ray Emission in Storm Clouds
Tropical thunderstorm with lightning, near the airport of Santa Marta, Colombia. Credit: Oscar van der Velde There’s more to thunderclouds than rain and lightning. Along with visible light emissions, thunderclouds can produce intense bursts of gamma rays, the most energetic form of light, that last for millionths of a second. The clouds can also glow steadily with gamma rays for seconds to minutes at a time.
Researchers using NASA airborne platforms have now found a new kind of gamma-ray emission that’s shorter in duration than the steady glows and longer than the microsecond bursts. They’re calling it a flickering gamma-ray flash. The discovery fills in a missing link in scientists’ understanding of thundercloud radiation and provides new insights into the mechanisms that produce lightning. The insights, in turn, could lead to more accurate lightning risk estimates for people, aircraft, and spacecraft.
Researchers from the University of Bergen in Norway led the study in collaboration with scientists from NASA’s Marshall Space Flight Center in Huntsville, Alabama, and NASA’s Goddard Space Flight Center in Greenbelt, Maryland, the U.S. Naval Research Laboratory, and multiple universities in the U.S., Mexico, Colombia, and Europe. The findings were described in a pair of papers in Nature, published Oct. 2.
The international research team made their discovery while flying a battery of detectors aboard a NASA ER-2 research aircraft. In July 2023, the ER-2 set out on a series of 10 flights from MacDill Air Force Base in Tampa, Florida. The plane flew figure-eight flight patterns a few miles above tropical thunderclouds in the Caribbean and Central America, providing unprecedented views of cloud activity.
The scientific payload was developed for the Airborne Lightning Observatory for Fly’s Eye Geostationary Lightning Mapper Simulator and Terrestrial Gamma-ray Flashes (ALOFT) campaign. Instrumentation in the payload included weather radars along with multiple sensors for measuring gamma rays, lightning flashes, and microwave emissions from clouds.
NASA’s high-flying ER-2 airplane carries instrumentation in this artist’s impression of the ALOFT mission to record gamma rays (colored purple for illustration) from thunderclouds.Credit: NASA/ALOFT team The researchers had hoped ALOFT instruments would observe fast radiation bursts known as terrestrial gamma-ray flashes (TGFs). The flashes, first discovered in 1992 by NASA’s Compton Gamma Ray Observatory spacecraft, accompany some lightning strikes and last only millionths of a second. Despite their high intensity and their association with visible lightning, few TGFs have been spotted during previous aircraft-based studies.
“I went to a meeting just before the ALOFT campaign,” said principal investigator Nikolai Østgaard, a space physicist with the University of Bergen. “And they asked me: ‘How many TGFs are you going to see?’ I said: ‘Either we’ll see zero, or we’ll see a lot.’ And then we happened to see 130.”
However, the flickering gamma-ray flashes were a complete surprise.
“They’re almost impossible to detect from space,” said co-principal investigator Martino Marisaldi, who is also a University of Bergen space physicist. “But when you are flying at 20 kilometers [12.5 miles] high, you’re so close that you will see them.” The research team found more than 25 of these new flashes, each lasting between 50 to 200 milliseconds.
The abundance of fast bursts and the discovery of intermediate-duration flashes could be among the most important thundercloud discoveries in a decade or more, said University of New Hampshire physicist Joseph Dwyer, who was not involved in the research. “They’re telling us something about how thunderstorms work, which is really important because thunderstorms produce lightning that hurts and kills a lot of people.”
More broadly, Dwyer said he is excited about the prospects of advancing the field of meteorology. “I think everyone assumes that we figured out lightning a long time ago, but it’s an overlooked area … we don’t understand what’s going on inside those clouds right over our heads.” The discovery of flickering gamma-ray flashes may provide crucial clues scientists need to understand thundercloud dynamics, he said.
Turning to aircraft-based instrumentation rather than satellites ensured a lot of bang for research bucks, said the study’s project scientist, Timothy Lang of NASA’s Marshall Space Flight Center in Huntsville, Alabama.
“If we had gotten one flash, we would have been ecstatic — and we got well over 100,” he said. This research could lead to a significant advance in our understanding of thunderstorms and radiation from thunderstorms. “It shows that if you have the right problem and you’re willing to take a little bit of risk, you can have a huge payoff.”
By James Riordon
NASA’s Earth Science News Team
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Last Updated Oct 02, 2024 EditorJenny MarderContactJames RiordonLocationMarshall Space Flight Center Related Terms
Earth Gamma Rays Goddard Space Flight Center View the full article
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By European Space Agency
Video: 00:03:12 There’s a mystery out there in deep space – and solving it will make Earth safer. That’s why the European Space Agency’s Hera mission is taking shape – to go where one particular spacecraft has gone before.
On 26 September 2022, moving at 6.1 km/s, NASA’s DART spacecraft crashed into the Dimorphos asteroid. Part of our Solar System changed. The impact shrunk the orbit of the Great Pyramid-sized Dimorphos around its parent asteroid, the mountain-sized Didymos.
This grand experiment was performed to prove we could defend Earth against an incoming asteroid, by striking it with a spacecraft to deflect it. DART succeeded. But that still leaves many things scientists don’t know: What is the precise mass and makeup of Dimorphos? What did the impact do to the asteroid? How big is the crater left by DART’s collision? Or has Dimorphos completely cracked apart, to be held together only by its own weak gravity?
That’s why we’re going back – with ESA’s Hera mission. The spacecraft will revisit Dimorphos to gather vital close-up data about the deflected body, to turn DART’s grand-scale experiment into a well-understood and potentially repeatable planetary defence technique.
The mission will also perform the most detailed exploration yet of a binary asteroid system – although binaries make up 15% of all known asteroids, one has never been surveyed in detail.
Hera will also perform technology demonstration experiments, including the deployment ESA’s first deep space ‘CubeSats’ – shoebox-sized spacecraft to venture closer than the main mission then eventually land – and an ambitious test of 'self-driving' for the main spacecraft, based on vision-based navigation.
By the end of Hera’s observations, Dimorphos will become the best studied asteroid in history – which is vital, because if a body of this size ever struck Earth it could destroy a whole city. The dinosaurs had no defence against asteroids, because they never had a space agency. But – through Hera – we are teaching ourselves what we can do to reduce this hazard and make space safer.
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By USH
The world is full of mysterious places, and Vottovaara Mountain in Russia's Republic of Karelia is one of them. This site has been revered for thousands of years by ancient Saami tribes and shamans, who considered it a sacred place surrounded with powerful energy.
Image credit: Universe Inside You
Vottovaara is home to numerous strange megalithic structures and ruins that many believe couldn't have formed naturally. Among these are around 1,600 sacred stones, known as "seids," arranged in a puzzling pattern. These stones, often unusually shaped, are precariously balanced on small rocks in ways that defy simple explanations. While scientists suggest that this was the result of natural processes during the Ice Age, the sheer number and precision of these balanced stones challenge the idea that they occurred by chance.
Another intriguing feature of Vottovaara is a structure referred to as "the well," which locals believe to be an ancient, man-made water reservoir.
As you climb Vottovaara, you'll notice an eerie transformation in the trees. None of the trees on the summit are older than a few decades, and while young pines and firs start growing normally, they soon begin to twist and deform in bizarre ways. This phenomenon is thought to be caused by some unknown energy affecting the trees.
Known as Death Mountain, Vottovaara also is believed to be connected to ancient spirits that are said to inhabit the area, adding to its aura of mystery.
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By European Space Agency
Launched less than two months ago, ESA’s EarthCARE satellite has already returned images from two of its four instruments. Now, it has also delivered the first images from its multispectral imager, showcasing various types of clouds and cloud temperatures worldwide. This instrument is set to add valuable context to the data from EarthCARE’s other instruments.
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