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August 21, 2025—Sometimes science pulls a 180. Plus, how meteorologists identify which storms turn into hurricanes, and a guide to decoding hurricane jargon and forecasts. —Andrea Gawrylewski, Chief Newsletter Editor | | A measles vaccination site at the Lubbock Public Health facility on April 09, 2025 in Lubbock, Texas. Brandon Bell/Getty Images | | On balance, science tends to follow a slow and incremental path: new observations build on previous findings, often over many years, contributing piecemeal to a larger body of knowledge. Thanks to the scientific method's use of replication, erroneous discoveries are slowly uncovered (they can't be replicated) and moved past. But every now and then, revelations arise that can dramatically accelerate our understanding of a given subject or take the field in unexpected directions—even 180 degrees in the other direction. For the most part, such reversals are rare. As disciplines grow older and bigger, they end up naturally absorbing people with minority points of view, writes journalist and author Charles C. Mann in our September issue. "Instead of entire disciplines executing a U-turn, these minority beliefs shift and twist while becoming acceptable to the majority." But major reversals do happen. In honor of Scientific American's 180th anniversary (we are the oldest continuously-running magazine in the U.S.!), we're taking a tour of some of science's 180 moments. In the coming newsletters we'll explore how science changed its mind—on cosmology, mRNA, nerve regeneration, the usefulness of plastics, and much more. Read the whole collection now in our latest issue, and be sure to check out a look back on the Scientific American legacy. Our new editor in chief, David M. Ewalt, writes in his first editor's letter that the world has become hostile to science: "Our leaders deny the existence of human-driven climate change and vilify vaccines that have saved hundreds of millions of lives. Schools lack funding for STEM courses, and budgets are slashed at leading research institutions such as the NIH, NASA and NOAA," he says. This makes Scientific American more vital than ever. We've stood up for science for 180 years, and we're not stopping now. Thank you, from all of us, for being a part of this science-loving community and supporting vital science journalism. | | The first signs of a hurricane can be seen days before the storm erupts. By looking at satellite images, tropical meteorologists can catch sight of these telltale warnings. Here are the conditions for hurricane development, according to Xingchao Shen, an assistant professor of meteorology at Penn State. - Distance from the equator: Tropical cyclones usually form at least 5 degrees from the equator. This is because the Coriolis force, which causes moving air to swirl, is weaker closer to the equator, enabling air to "spin up."
- Warm sea surface temperatures: At least 26.5 degrees Celsius (about 80 Fahrenheit) is the prime temperature for a hurricane to form. The storm absorbs heat and moisture from the warm water.
- Atmospheric instability and moisture: The atmosphere needs to be unstable for tropical cyclones to form, which means that warm surface air rises and remains warmer than the surrounding air, allowing it to keep rising and form thunderstorms. Additionally, there needs to be a lot of moisture, because dry air can cause clouds to evaporate and weaken the storm's motion.
- Low vertical wind shear: Strong changes in wind direction or speed at different altitudes, called vertical wind shear, can tear a developing hurricane apart. Low levels allow the storm to form.
What the experts say: One of the first tools meteorologists use to spot these conditions is satellite images, which provide real-time data on all the conditions listed above. "However, satellite observations alone don't provide enough information for meteorologists to know which tropical waves are likely to develop into hurricanes," says Shen. He and his team have started to incorporate real-time satellite data into computer forecast models in a process known as data assimilation. "As a result, forecasters can benefit from significantly enhanced predictive capabilities, particularly in anticipating the formation and progression of hurricanes." —Andrea Tamayo, newsletter writer More on hurricanes: | | National Hurricane Center (base map); Amanda Montañez (hurricane path graphics) | | | | |
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Emmanuel Barde Elisha is a research coordinator with the Africa Nature Investors Foundation in Gashaka-Gumti National Park, Nigeria. "My job is to coordinate the foundation's research activities in the 6,400-square-kilometer park, which is Nigeria's largest protected area," he says. The park houses many vulnerable species, including the Nigeria–Cameroon chimpanzee (Pan troglodytes ellioti). "I'm always excited when I see chimps," he says. "Poaching made them wary of humans, but now I think they are starting to understand that we can protect them, too." Nature | 3 min read | | Hurricane Erin is hundreds of miles from the shores of the Eastern U.S. but it's still causing coastal surge, giant waves, beach erosion and extreme rip currents. Check out this animated image from NOAA of Erin's cloud coverage—huge! The storm's winds are spanning 400 miles across, nearly twice what a normal category 2 hurricane's winds measure, according to the New York Times. Sending a small thanks to the universe that this one is staying at sea. | | —Andrea Gawrylewski, Chief Newsletter Editor
P.S. Yesterday I included a wonderful anatomical illustration of how cerebral spinal fluid flushes toxins out of the brain. Sadly I credited the wrong artist for the creation of this image. It should have been: David Cheney. | | | | |
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