Puzzle of the Day: How Many Circles Balance the Scale?
Three balance scales, three shapes, and one empty pan. How many circles balance scale C?
NASA Opens Final Bidding for Private Space Stations to Replace the ISS: Who Are the Contenders?
NASA’s final call for commercial space stations is out, with bids due Dec. 8, 2026. What NASA is buying, and how Axiom, Vast, Starlab, Orbital Reef and others compare.
The Molecule Nobody Wanted: How mRNA Spent 60 Years Becoming a Vaccine
Messenger RNA was discovered in 1961 and spent decades as a molecule nobody wanted. Here is how fat bubbles, a stubborn biochemist, a photocopier meeting and a clue from transfer RNA turned it into the fastest vaccine ever made.
Best CO2 Monitors for Home (2026): Six Indoor Air Quality Monitors Compared
Six indoor CO2 and air quality monitors compared: the accurate Aranet4, a radon-sensing Airthings, a HomeKit Qingping with PM2.5, a smart Govee, a $43 Temtop, and a no-app Inkbird.
Nature’s Nuclear Reactor: How Uranium in Gabon Ran Its Own Chain Reaction Two Billion Years Ago
In 1972 a French lab found uranium from a Gabon mine was short on uranium-235. The reason: about two billion years ago, the ore had run its own nuclear chain reactions, pulsing on and off like a geyser for hundreds of thousands of years. Here is how nature built a reactor, and what it still teaches scientists.
The Man Who Went Through 26 Pacemakers: How a Homemade Gadget Learned to Run the Human Heart
In 1958 a Swedish engineer got the first fully implanted pacemaker. It failed in three hours, and he went on to use 26 of them. Here is how the pacemaker went from a homemade epoxy disc to a capsule inside the heart.
Starfish Prime: The 1962 H-Bomb in Space That Lit Up Hawaii and Crippled Satellites
In July 1962 the United States exploded a hydrogen bomb 250 miles above the Pacific. It lit up the sky over Hawaii, knocked out streetlights 900 miles away, and created a radiation belt that helped kill satellites, including Telstar. Here is what happened and why it still matters.
The Dead Salmon in the Scanner: How fMRI Reads the Brain, and How It Can Fool Us
A dead fish once seemed to read human emotions in a brain scanner. Here is how functional MRI actually works, why the salmon lit up, and what brain scans can and can’t tell us.
Best Compact Binoculars for Concerts, Theater, and Travel (2026): Six Picks Compared
Six compact binoculars for concerts, theater, sports, and sightseeing, compared: a pocket Nikon, a close-focusing Pentax, a wide-view arena pick, a premium Zeiss, a $60 budget pair, and our all-around favorite.
The Tunguska Event: How a Space Rock Flattened a Siberian Forest Without Leaving a Crater
On June 30, 1908, something from space exploded over a remote Siberian forest and flattened trees across 830 square miles, yet left no crater. Here is what scientists found, what they still argue about, and how Tunguska shapes planetary defense today.
Why Astronauts Lose Bone in Space, and How They Fight to Keep It
Weightlessness strips the load from astronauts’ skeletons, and their hips and spines thin fast. Here is why, how space crews fight back with heavy lifting, treadmills, and drugs, and why Mars raises the stakes.
Too Sure It Couldn’t Happen: How AI Caught Mathematicians Off Guard
Mathematicians assumed machine proofs of hard open problems were years away. Then AI won IMO gold and disproved an Erdős conjecture from 1946.
The Great Stink: How a Sweltering Summer of Sewage Forced London to Build Its Sewers
In the hot summer of 1858, the Thames stank so badly that Parliament finally acted. How the Great Stink led Joseph Bazalgette to build the sewers London still uses.
Why Your Power Station Says LiFePO4: The Iron Battery Chemistry, Explained
Flip over almost any portable power station sold today and the spec sheet says the same odd thing: LiFePO4, or
Best Dash Cams for Everyday Drivers (2026): Six Picks From Tiny to Three-Channel
Six dash cams you can buy now, compared: a tiny Garmin, a 4K favorite with a rear camera, a three-channel rideshare setup, and a radar-equipped parking guard, with who each one suits.
The Year Without a Summer: How a Volcano Brought Snow to New England in June
On June 6, 1816, snow fell on Albany, New York. A few days later, the ground froze hard in the
Why Cast Iron Turns Nonstick: The Chemistry of Seasoning, Explained
A brand-new cast iron skillet is just a slab of gray iron poured into a sand mold. Leave it bare
Project Azorian: How the CIA Tried to Steal a Soviet Sub From Three Miles Down
In March 1968, a Soviet ballistic-missile submarine named K-129 left Kamchatka for a routine Pacific patrol and never came home.
The Carrington Event: The 1859 Solar Storm That Set Telegraphs on Fire
Just after 11 o’clock on the morning of September 1, 1859, an English astronomer named Richard Carrington was sketching sunspots
Best Cast Iron Skillets for Searing, Baking, and Everyday Cooking (2026)
Six cast iron skillets you can buy now, compared: budget classics, lighter smooth heirloom pans, and an enameled option, with sizes, weights, and who each one suits.