Cosmic Muons Can 3D-Scan Hurricanes

Superenergetic cousins of electrons boldly go into the heart of megastorms, where terrestrial tech can’t reach

2 min read
drawing of a mushroom cloud with black background on left side and yellow and orange background on the right side

The redder areas represent low-pressure warm air, and the green areas are higher-pressure cooler air. The cyclone in this image is about 15 kilometers tall. A line drawing approximating the shape overlays the visualization data.

Hiroyuki KM Tanaka

Using exotic particles known as muons that regularly blast Earth, scientists can now scan deep inside hurricanes in 3D, peering into areas of the storms that are too difficult to see with conventional techniques. These findings suggest that muon detectors may lead to new and better hurricane early-warning systems, researchers say.

A muon is similar to an electron, except it weighs more than 200 times as much. That is about the difference between an adult person and a small elephant.

When high-energy particles from deep space known as cosmic rays hit Earth’s atmosphere, they can generate muons. Muons constantly shower Earth from every angle—approximately one muon hits every square centimeter of Earth every minute at sea level.

Muons often pass through matter easily, but dense objects or gigantic bodies can absorb or scatter them in a similar way to X-rays. By capturing a large number of muons passing through something, researchers can reconstruct an image of it, a technique known as muon tomography, also known as muography.

Scientists have used muography to analyze Fukushima’smelted nuclear cores, scan the Great Pyramid of Giza, and see deep inside volcanoes, tsunami-like waves, and shipping containers. Now, for the first time, a new study explored using muography to probe tropical cyclones (also known as hurricanes or typhoons, depending on the location).

Although satellite imagery and drone missions can peer at hurricanes, they face challenges gathering data on the 3D nature of air pressure and density inside tropical cyclones. These details are often critical to predicting how these storms might develop in the future.

The scientists had their array of muon detectors analyze eight tropical cyclones that approached Kagoshima in western Japan in 2016, 2019, and 2021. They found they could see air density and pressure variations in the hearts of these storms. “The warm cores of the cyclones were clearly imaged,” says study lead author Hiroyuki Tanaka, a physicist at the University of Tokyo.

The vertical and horizontal pressure variations the researchers detected are connected to wind strength. “The fact that the warm core was clearly imaged indicates that the wind-speed distributions inside a cyclone could be calculated,” Tanaka says. Calculating the wind-speed distribution inside a tropical cyclone may in turn help scientists estimate its power and predict where it might go, he says.

The researchers estimate that muon detectors must be located within 300 kilometers of storms to analyze muons zipping through them. Currently land-based and airplane-based muography devices exist, Tanaka says. “There are no ship-based ones thus far, but they are naturally possible,” he adds.

By combining computer simulations and muographic data, “we may be able to design a completely new kind of cyclone forecast system,” Tanaka says. He adds that future research may analyze storms at different scales, not only tropical cyclones but also more local weather conditions.

The scientists detailed their findings last month in the journal Scientific Reports.

The Conversation (1)
hans tenkink09 Nov, 2022

A muon is similar to an electron, except it weighs more than 200 times as much. That is about the difference between an adult person and a small elephant.

Must be a very tiny adult.

Europe Expands Virtual Borders To Thwart Migrants

Our investigation reveals that Europe is turning to remote sensing to detect seafaring migrants so African countries can pull them back

14 min read
A photo of a number of people sitting in a inflatable boat on the water with a patrol ship in the background.

Migrants in a dinghy accompanied by a Frontex vessel at the village of Skala Sikaminias, on the Greek island of Lesbos, after crossing the Aegean sea from Turkey, on 28 February 2020.


It was after midnight in the Maltese search-and-rescue zone of the Mediterranean when a rubber boat originating from Libya carrying dozens of migrants encountered a hulking cargo ship from Madeira and a European military aircraft. The ship’s captain stopped the engines, and the aircraft flashed its lights at the rubber boat. But neither the ship nor the aircraft came to the rescue. Instead, Maltese authorities told the ship’s captain to wait for vessels from Malta to pick up the migrants. By the time those boats arrived, three migrants had drowned trying to swim to the idle ship.

The private, Malta-based vessels picked up the survivors, steamed about 237 kilometers south, and handed over the migrants to authorities in Libya, which was and is in the midst of a civil war, rather than return to Malta, 160 km away. Five more migrants died on the southward journey. By delivering the migrants there, the masters of the Maltese vessels, and perhaps the European rescue authorities involved, may have violated the international law of the sea, which requires ship masters to return people they rescue to a safe port. Instead, migrants returned to Libya over the last decade have reported enslavement, physical abuse, extortion, and murders while they try to cross the Mediterranean.

If it were legal to deliver rescued migrants to Libya, it would be as cheap as sending rescue boats a few extra kilometers south instead of east. But over the last few years, Europe’s maritime military patrols have conducted fewer and fewer sea rescue operations, while adding crewed and uncrewed aerial patrols and investing in remote-sensing technology to create expanded virtual borders to stop migrants before they get near a physical border.

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