Tsunamis
These awe-inspiring waves are typically caused by large, undersea earthquakes at tectonic plate boundaries. When the ocean floor at a plate boundary rises or falls suddenly, it displaces the water above it and launches the rolling waves that will become a tsunami.
Most tsunamis–about 80 percent–happen within the Pacific Ocean's 'Ring of Fire,' a geologically active area where tectonic shifts make volcanoes and earthquakes common.
Tsunamis may also be caused by underwater landslides or volcanic eruptions. They may even be launched, as they frequently were in Earth's ancient past, by the impact of a large meteorite plunging into an ocean.
Tsunamis race across the sea at up to 500 miles (805 kilometers) an hour—about as fast as a jet airplane. At that pace, they can cross the entire expanse of the Pacific Ocean in less than a day. And their long wavelengths mean they lose very little energy along the way.
More than 1,500 people died in Rikuzentakata, one of several towns eradicated by a tsunami that hit Japan.
In deep ocean, tsunami waves may appear only a foot or so high. But as they approach shoreline and enter shallower water they slow down and begin to grow in energy and height. The tops of the waves move faster than their bottoms do, which causes them to rise precipitously. What Happens When It Hits Land
A tsunami's trough, the low point beneath the wave's crest, often reaches shore first. When it does, it produces a vacuum effect that sucks coastal water seaward and exposes harbor and sea floors. This retreating of sea water is an important warning sign of a tsunami, because the wave's crest and its enormous volume of water typically hit shore five minutes or so later. Recognizing this phenomenon can save lives.
A tsunami is usually composed of a series of waves, called a wave train, so its destructive force may be compounded as successive waves reach shore. People experiencing a tsunami should remember that the danger may not have passed with the first wave and should await official word that it is safe to return to vulnerable locations.
Some tsunamis do not appear on shore as massive breaking waves but instead resemble a quickly surging tide that inundates coastal areas.
The best defense against any tsunami is early warning that allows people to seek higher ground. The Pacific Tsunami Warning System, a coalition of 26 nations headquartered in Hawaii, maintains a web of seismic equipment and water level gauges to identify tsunamis at sea. Similar systems are proposed to protect coastal areas worldwide. Lightning Strikes A supercell thunderstorm strikes in South Dakota. Among the most severe storms, supercells can bring strong winds, hail, and even tornadoes. (See more extreme weather pictures.) Photograph by Jim Reed, National Geographic
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Yahoo
11-07-2025
- Yahoo
'Ball Lightning' Caught on Film After Storm in Canada
During a recent lightning storm, a couple from Canada caught a rare weather mystery on camera. Right from their porch, Ed and Melinda Pardy watched as a lightning bolt struck the land less than a kilometer from their home. In the bolt's wake, a brilliant ball of blue light was left hovering above the ground. The couple managed to capture a 23-second video of the strange apparition. "It looks like a firebolt, but not really, it's the wrong color," Melinda Pardy can be heard saying in the background of the footage, which was provided to several Canadian broadcasters. According to an interview with Canada's CTV News, the bizarre globe of bright light was about one to two meters in diameter, and it hovered above the ground for about a minute before it went out with a 'pop'. Related: Ed Pardy thinks it may have been a rare glimpse of ball lightning, a hypothetical weather phenomenon defined by thousands of eyewitness accounts collected over the centuries. Some have even reported fiery orbs flying through their windows. Despite all the anecdotes, there's no real scientific explanation for the claimed events. The size of the observed light sphere, its color, and behavior can vary quite a lot, so it's hard to confirm if all the stories are due to the same physics. In recent decades, scientists have tried to generate models of plasma balls in the lab, to understand how orbs of light could move around and last for so long. But because of their random and rare nature, real-world examples are much harder to study. In 2014, scientists in China got lucky. They filmed what they argue is the first video of ball lightning, capturing the incident by accident. Upon further analysis, they found evidence that ball lightning is composed of tiny bits of soil, which could be vaporized by lightning and set a-glow. Their observations and measurements were published in a peer-reviewed paper, but some scientists disagree on the physics. Instead, they suspect ball lightning is the result of light, trapped within a sphere of highly compressed air. No scientist has yet confirmed the short video from Alberta is footage of ball lightning, but the Pardy couple says they have been approached by researchers. "If it is ball lightning," veteran storm chaser George Kourounis told CTV News, "then this is one of the best ball lightning videos I've ever seen." But there are plenty of online skeptics. Some have suggested the curious ball of electricity could be the result of a power flash on a high voltage line, which can't be seen in the video, although the Pardy's say there are no powerlines close by. Frank Florian, senior manager of planetarium and space sciences at the TELUS World of Science, told Global News that whatever the couple saw, it was a very strange weather phenomenon. "It could be ball lightning or it could be something that's more of an artifact of a lightning strike itself," he said. This may be one of those mysteries we never get an answer to. Expired Cans of Salmon From Decades Ago Contained a Huge Surprise Melting Glaciers Could Reawaken Hundreds of Earth's Volcanoes Blue Sharks May Be Secret Chameleons, Scientists Discover
Forbes
10-07-2025
- Forbes
Spectacular ‘Space Lightning' Photographed By NASA Astronaut
A "sprite" over Mexico as seen from the International Space Station on July 3, 2025 by astronaut ... More Nicole Ayers. An astronaut on the International Space Station has captured a rare kind of lightning called a sprite while traveling 250 miles above the Texas–Mexico border. Referred to as 'space lightning' and compared to a jellyfish in shape, the rare weather phenomenon was captured on camera by NASA astronaut Nichole Ayers. The rare image was taken on July 3 by pilot Nichole Ayers, who launched to the ISS on March 14, 2025, as part of the SpaceX Crew-10 mission. It shows an ethereal crimson jellyfish-like flash shooting from the tops of clouds and into space. It's known as a 'red sprite,' but also as a transient luminous event, lightning in Earth's upper atmosphere. According to NASA, these colorful, bright, faster-than-lightning flashes are generated above the clouds by thunderstorms. Ayers' Explanation Of The 'Sprite' 'Just. Wow. As we went over Mexico and the U.S. this morning, I caught this sprite,' wrote Ayers on X/Twitter. 'Sprites are TLEs or Transient Luminous Events that happen above the clouds and are triggered by intense electrical activity in the thunderstorms below. We have a great view above the clouds, so scientists can use these types of pictures to better understand the formation, characteristics, and relationship of TLEs to thunderstorms.' In a later message, she stated that it was a gigantic jet, another type of TLE. 'So cool to learn as we go up here,' she wrote. The image also shows the glow of Dallas, Austin, San Antonio and Houston to the northeast, with Torreón, Mexico, to the southwest. 'Our hearts go out to the families affected by the flooding in the Texas Hill Country this weekend,' added Ayers. A "sprite" over Mexico as seen from the International Space Station on July 3, 2025 by astronaut ... More Nicole Ayers. How The Image Was Taken The ISS is the best observation point humankind has for monitoring Earth at night but photographing lightning takes a huge amount of patience and trial and error. Astronauts on the ISS take photos from the Cupola (Italian for dome), an observatory module that has seven windows and allows photography of Earth. Ayers took the shot using a Nikon Z9 and a 50mm lens as part of a time-lapse project during which she took multiple images. 'To record a photo like this takes skill to set up the camera but more than that, the knowledge of what lightning systems are likely to create sprites and the willingness to take 2000-5000 images where only one will record a sprite,' wrote NASA astronaut and astrophotographer Don Pettit on X/Twitter, who arrived back from the ISS on April 19. 'Kudos to Nicole for her imagery efforts!' The Moon's shadow, or umbra, is pictured covering portions of the Canadian provinces of Quebec and ... More New Brunswick and the American state of Maine in this photograph from the International Space Station as it soared into the solar eclipse from 261 miles above. The ISS And The 'Great North American Eclipse' Perhaps the most widely seen images taken from the ISS were those of the total solar eclipse on April 8, 2024. NASA flight engineers Matthew Dominick and Jeanette Epps captured unique views of the moon's shadow over part of Maine, U.S. and Quebec and New Brunswick, Canada. For the shots, NASA carefully adjusted the altitude of the orbiting laboratory for months, leading up to the final total solar eclipse in the contiguous U.S. until 2044. Wishing you clear skies and wide eyes.
Yahoo
08-07-2025
- Yahoo
Astronaut captures amazing red sprite phenomenon from space
Speeding around the Earth at 28,000 km/h, NASA astronaut Nichole Ayers captured an incredible view of a phenomenon known as a red sprite. Here's the science behind this 'transient luminous event'. Lightning flashes through the air several million times every day, all around the world. The vast majority of those bolts occur inside clouds, between different clouds, or between the clouds and the ground. They happen as a result of large build-ups of negative or positive charge within clouds and along the ground, and act to balance out those charges. A small fraction of these discharges — about one in every 1,600 on average — actually occur above the clouds. These 'transient luminous events' or TLEs happen when the charge build-up within a thunderstorm balances out between the cloud and the upper atmosphere, near the edge of space. The different forms of transient luminous events. (NOAA) On July 3, 2025, from her vantage point in the cupola of the International Space Station, astronaut Nichole Ayers was snapping pictures of thunderstorms as the station passed over Mexico and the United States. In a spectacular feat of timing, one of her photographs managed to catch one of these TLEs, known as a red sprite, right in the middle of discharging! This cropped view of the image snapped by astronaut Nichole Ayers zooms in on the red sprite she captured on July 3, 2025. (astro_ayers/X/NASA) READ MORE: Sprites are rapid flashes of red light that occur high up in the atmosphere, over 50 kilometres above the ground. While they are referred to as upper atmospheric lightning, the only thing red sprites have in common with the typical form of lightning we see is the movement of electric charge from one part of the atmosphere to another. Other than that, they are very different phenomena. Another sprite seen from the ISS on August 10, 2015, over Central America. (NASA) Lightning only occurs in the lowest part of the atmosphere — the troposphere — and as it flashes through the air, it heats that air to temperatures hotter than the surface of the Sun. Sprites, on the other hand, only happen in the thin upper atmosphere — the mesosphere and ionosphere — and they are a cold plasma phenomenon. Their glow probably has more in common with that of a fluorescent light bulb, or the Aurora Borealis. The colour of a sprite comes from the fact that our atmosphere is mostly nitrogen. When an air molecule becomes energized, one of the electrons orbiting around it will jump up to a higher level. To return to its 'ground state', where the electron drops back down into its normal orbit, it emits a flash of light to dump its excess energy. In the case of nitrogen, the light emitted has a very strong red component, along with a bit of blue and purple. This immense 'jellyfish sprite' was captured over a storm in West Texas on July 2, 2020. (Stephen Hummel) It seems that we've known about sprites, or at least transient luminous events in general, for around 300 years. According to NASA, pilots apparently were reporting sightings of them since the first military and commercial flights in the early part of the 20th century. It wasn't until 1989, though, that they were finally caught on camera. While we know what sprites are, explaining how they form is a bit more challenging. However, here's what we know, as well as what researchers speculate, about the process. The formation of a sprite starts inside a thunderstorm. There, the exchange of electrons between colliding ice crystals and snow pellets produces distinct regions of electric charge within the cloud. Weak positive charge collects at the base, strong negative charge accumulates in the middle, and strong positive charge builds at the top. Most often, lightning will balance the negative charge at the core of the cloud by linking it with a region of positive charge on the ground, inside another nearby cloud, or even within the same cloud. This is the common negative lightning that occurs millions of times per day. The likely distribution of electric charge of a cumulonimbus cloud has been drawn onto this User-generated Content image of a storm taken on Aug 27, 2022, from Carrot River, SK, and uploaded to the Weather Network's UGC gallery. (Fran Bryson/UGC) Occasionally, though, the strong positive charge accumulated at the top of the thunderstorm cloud has a chance to discharge, by linking with a region of negative charge along the ground. When this happens, we see a powerful stroke of positive lightning. This appears to be the point where a sprite has a chance to form. Normally, as a thunderstorm cloud is rolling along through the troposphere, at the same time, the air much higher up has a strong positive charge due to interactions with particles streaming into the atmosphere from space. Usually, this upper atmospheric positive charge doesn't have anywhere to go. It needs a region of negative charge to balance out. The negatively charged core of the thunderstorm could do this. However, the positive charge accumulated at the top of the cloud stands in the way. When a positive lightning strike lances out between the top of the cloud and the ground, though, much of that excess positive charge is stripped away. At that moment, the negative charge in the middle of the cloud becomes directly exposed to the positively charged mesosphere, allowing a connection to form. Based on observations, sprites are almost always preceded by a positive lightning strike. Thus, they are a potential trigger for the phenomenon. Even so, a positive lightning strike doesn't always guarantee that a sprite will appear. Thus, it's likely that some other component needs to be present for the sprite to form. That other component could be gravity waves. The video above was recorded from atop Mount Locke in West Texas, in May 2020, by Stephen Hummel, the dark sky specialist at the McDonald Observatory. In the video, gravity waves can clearly be seen, illuminated by a phenomenon called airglow, radiating away from a storm along the horizon to the lower right. Amid the gravity waves streaming through the field of view, several sprites are also captured (watch closely at 1s, 3s, 7s and 12s into the video). Gravity waves behave like ripples on the surface of a pond, with air rising and falling as it tries to balance out the forces of gravity and buoyancy. When a powerful thunderstorm's strong updraft winds reach the top of the troposphere, they are deflected by the stable air of the lower stratosphere, and are forced to spread outward instead. Research has already shown that the action of gravity waves can have an impact on the upper atmosphere. This could be another way they influence what happens, far above the surface. Now, exactly how gravity waves might play a role in sprite formation isn't yet known. Some researchers have noted that sprites appear to form at what they call "plasma irregularities" in the ionosphere. However, these irregularities are themselves, also a mystery. It could be that gravity waves play a role in forming these irregularities. For now, though, no one knows. To understand this phenomenon better, more sightings, more captures, and more research are required. Click here to view the video
