How Hummingbirds Stay Still in Midair
Hummingbirds are the only vertebrates capable of sustained hovering. Powered wing strokes on both the downbeat and upbeat help explain their unusual control in the air.
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Why GPS Needs Einstein’s Relativity to Find You
GPS satellite clocks are pushed in opposite directions by speed and gravity. Their net 38-microsecond daily difference has to be accounted for to keep positioning accurate.
How Can Archaeologists Tell an Ancient Iron Furnace Was Reused?
Grouped furnace remains, slag, and ore chemistry led researchers to cautiously infer that some ancient bloomery shafts were used more than once.
Why Do We See the Sun 8 Minutes in the Past?
Sunlight takes about 8 minutes and 20 seconds to cross the roughly 93 million miles between the Sun and Earth.
How Can an Algorithm Shrink a Photonic Circuit?
Inverse design starts with the desired behavior of light and searches backward for a structure that can produce it. In one study, a mode sorter used about one five-hundredth the footprint of representative conventional designs.
How the Pony Express Became a Legend in Just 18 Months
The Pony Express crossed more than 1,800 miles in about ten days, yet the service lasted only from April 1860 to October 1861.
Why Does One NOAA Climate Station Use Three Thermometers?
Each U.S. Climate Reference Network station keeps three independent temperature streams, then uses their agreement to derive one official hourly value.
How Can a Wood Frog Survive Winter Without a Heartbeat?
A frozen wood frog may show no heartbeat, breathing, or muscle movement. Its survival depends on controlling where ice forms and protecting cells with glucose.
What Do Microglia Do in the Brain?
Microglia are resident immune cells that patrol brain tissue, clear debris, and help maintain the connections that let neurons communicate.
Why Was the Star-Spangled Banner Flag So Enormous?
The Fort McHenry flag that inspired the U.S. national anthem was originally 30 by 42 feet. Its size was a practical choice, and making it required an unusually large workspace.