Why Octopuses Have Three Hearts and Blue Blood
An octopus runs its unusual circulation system with three hearts and copper-based blue blood. Here is how those pumps divide the work.
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How Lightning Makes Air Hotter Than the Sun’s Surface
A lightning channel can heat nearby air to about 54,000°F in a fraction of a second. That explosive heating creates the shock wave we hear as thunder.
Why Sunsets on Mars Look Blue
Mars is famous for rusty red landscapes, yet its sunsets often glow blue around the Sun. Fine airborne dust rearranges the colors of Martian twilight.
The First UPC Barcode Scan Was a Pack of Gum
A routine supermarket purchase on June 26, 1974, became a milestone in retail technology. The first product scanned with a UPC barcode was a pack of chewing gum.
The Sun Swaps Its Magnetic Poles About Every 11 Years
The Sun’s magnetic north and south poles reverse approximately every 11 years. Sunspots help scientists track this repeating solar cycle.
Why a Day on Venus Is Longer Than Its Year
Venus rotates so slowly that one complete turn takes 243 Earth days, while its orbit around the Sun takes only 225. Its backward spin makes the planet’s calendar even stranger.
Why the Statue of Liberty Turned Green
Lady Liberty began with a brown copper surface. Here is how natural oxidation created her green patina—and why her copper skin is only about as thick as two pennies.