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August 4, 2025—How hot is it outside? The answer is surprisingly tricky. Also, more earthquake activity, a volcano eruption and wildfire smoke. It's been a long summer. —Andrea Gawrylewski, Chief Newsletter Editor | | A massive column of ash erupts from the Krasheninnikov volcano in Russia's eastern Kamchatka region on August 3, 2025. Sheldovitsky Artem Igorevich/IViS/Handout/Anadolu via Getty Images | | - Russia's Krasheninnikov volcano erupted for the first time in centuries following the 8.8 magnitude earthquake that struck less than 150 miles away last week. | 2 min read
- Speaking of earthquakes: A 3.3 magnitude quake rumbled the New York City region Saturday night. It's the second in less than two years. What does this mean? | 2 min read
- Some mathematicians don't believe in infinity. They have proposed an alternative branch of mathematics that relies only on finitely constructible quantities. | 4 min read
- Smoky skies are forecasted for Northeastern states today and tomorrow. Wildfire smoke from Canada is moving eastward from the Midwest. | 2 min read
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We're Turning 180 Years Old!  That's right! This month, Scientific American will have been in publication for 180 years—the oldest continuously published magazine in the country. For all that time, our cover images have invited readers on voyages of discovery—from deep oceans to distant galaxies. Now it's your turn to embark on an adventure! Snap a picture of a Scientific American print issue in a setting that reflects or complements the theme of the cover. Post your photo on Instagram, TikTok, LinkedIn or BlueSky. Include your name and photo location in the caption. Tag us and use #SciAmInTheWild. Or you can email your photo to contests@sciam.com. Include your name, the photo location, and attach your image. The contest runs from August 1 to September 5. Grand prize: An Unlimited subscription to Scientific American, plus an awesome selection of gadgets and gear to fuel your next expedition. | | | | |
Turns out, it's not a straightforward question. Temperature is the baseline measurement, usually taken by stations around the world at a few feet off the ground. Air temperatures can feel different depending on whether we're in direct sun or shade, in a breeze or still air. Other measurements: - Humidity: the measure of the amount of water in the air. It can make 78 degrees F feel like 85 and oh-so-sticky because the water vapor in the air prevents sweat from evaporating off skin, which would otherwise cool you down.
- Dew point: a measurement related to water vapor in the air. It is the temperature the air would have to be cooled to for the water vapor in the atmosphere to start condensing out and forming liquid. When dew points are high, sweat will cling to your body longer and make everything feel yuck (the scientific term).
| | Zane Wolf; Source: National Weather Service (data) | | - The heat index: calculated based on air temperature and humidity and is meant to give you an accurate idea of what it really feels like outside. News stations and weather reports often report the heat index, but it can have limitations. It is based on assumptions about body size and health. Plus, its parameters aren't as relevant in the Western U.S. where air is typically drier.
| | The future: The National Weather Service and some schools and sports teams are incorporating more sophisticated heat metrics, like the Wet-Bulb Globe Temperature (which was invented by the military in the 50s). It accounts for not only the air temperature and humidity but also sun exposure and wind speed. | | | | |
- The current administration should rally around Project Artemis, NASA's plan to get astronauts back to the moon, says Matthew Beddingfield, a writer and attorney working on a book about the Apollo 1 space mission. "The success of this new moonshot will at the very least prevent space dominance from adversaries, including Russia and China," he says. The project will also create jobs and is supported by the public. "The administration needs to move fast and nominate a leader for NASA who will prioritize Artemis and its core mission," he writes. "It needs to walk back plans to slim down government that are causing 2,000 senior officials to leave NASA at a time when leadership matters more than ever before." | 6 min read
| | Divide this figure into three parts that can be arranged into a square. The parts must not be folded over to make their current back the front, they must not overlap, and there must not be any gaps in the square. Click here for the solution. | | Having lived through several heat waves the past couple years, I've become fixated on dew point more than any other measure of heat. It's much more accurate than relative humidity as a predictor of how comfortable you'll feel outside. Keep track of the dew point for a week or so and see what you think. A dew point around 55 degrees F or less will be pretty comfortable, but anything creeping toward a dew point of 65 degrees F will start to feel sticky. | | I hope you participate in our Scientific American "cover in the wild" contest! (I've seen the prize box and it's pretty sweet.) Please send any questions about it to me at: newsletters@sciam.com. See you tomorrow! —Andrea Gawrylewski, Chief Newsletter Editor
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