What Is the Fastest Animal in the World?


People seem to have an innate fascination with speed. We like to watch high-performance cars circle tracks—or tempt speed limits on highways ourselves—and celebrate Olympic athletes like Usain Bolt, who probably is the fastest man on two feet at the moment.

That curiosity often extends beyond machines and elite athletic competition. What has nature done to gift certain animals with enough momentum to overcome prey? And is there really such a thing as the fastest animal in the world?

If all we really want to determine is which animal can cover the distance from point A to point B in the shortest amount of time, then that lingering fact you may have heard about cheetahs is true. The sinewy cat found mainly in Africa can hit speeds of 64 mph, roughly the speed limit of many major U.S. highways. (Other studies have pegged it at 58 mph.)

That’s under ideal conditions. Normally, cheetahs sprint because they’re after dinner, and if that dinner tries to evade capture, the cheetah will need to stop and resume speed often to keep up. Because of the unpredictable nature of their prey, a cheetah often keeps its speed closer to 33 mph.

When we associate the fastest animal in the world with linear forward movement on land, the cheetah is probably going to come out on top. But not all animals use limbs to propel themselves vertically. The falcon, for example, takes advantage of gravity to descend on prey from above. Like free-falling parachutists, falcons have been known to reach high speeds on descent. The higher the starting point, the more speed they can achieve: One peregrine falcon that began at 15,000 feet (thanks to some human help) reached 183 mph.

The cheetah is also outperformed in water by the sailfish, which can reach speeds of 68 mph when they're breaching waves. For context, a sailfish could swim 200 meters in just 10 seconds; Michael Phelps would need well over a minute to cover the same distance. Killer whales can swim 34 mph—incredibly speedy considering their heft.

Asking which is the fastest animal in the world is a tricky question. Humans tend to think of "fast" in relation to the linear movement we see in racing, but fast can mean a variety of things in the wild. While you may never see most of these animals shift into gear in person, at least one domesticated creature can hit the gas: The greyhound tops out at 43 mph.

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Are Any of the Scientific Instruments Left on the Moon By the Apollo Astronauts Still Functional?

Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Heritage Space/Heritage Images/Getty Images

C Stuart Hardwick:

The retroreflectors left as part of the Apollo Lunar Ranging Experiment are still fully functional, though their reflective efficiency has diminished over the years.

This deterioration is actually now delivering valuable data. The deterioration has multiple causes including micrometeorite impacts and dust deposition on the reflector surface, and chemical degradation of the mirror surface on the underside—among other things.

As technology has advanced, ground station sensitivity has been repeatedly upgraded faster than the reflectors have deteriorated. As a result, measurements have gotten better, not worse, and measurements of the degradation itself have, among other things, lent support to the idea that static electric charge gives the moon an ephemeral periodic near-surface pseudo-atmosphere of electrically levitating dust.

No other Apollo experiments on the moon remain functional. All the missions except the first included experiment packages powered by radiothermoelectric generators (RTGs), which operated until they were ordered to shut down on September 30, 1977. This was done to save money, but also because by then the RTGs could no longer power the transmitters or any instruments, and the control room used to maintain contact was needed for other purposes.

Because of fears that some problem might force Apollo 11 to abort back to orbit soon after landing, Apollo 11 deployed a simplified experiment package including a solar-powered seismometer which failed after 21 days.

This post originally appeared on Quora. Click here to view.

What Makes a Hotel Breakfast 'Continental'?

Hotels often offer a complimentary pastry and fruit breakfast.
Hotels often offer a complimentary pastry and fruit breakfast.
tashka2000/iStock via Getty Images

The continental breakfast, which is typically made up of pastries, fruit, and coffee, is often advertised by hotels as a free perk for guests. But why is it called continental, and why don’t patrons get some eggs and bacon along with it?

The term dates back to 19th century Britain, where residents referred to mainland Europe as “the continent.” Breakfast in this region was usually something light, whereas an English or American breakfast incorporated meat, beans, and other “heavy” menu options.

American hotels that wanted to appeal to European travelers began advertising “continental breakfasts” as a kind of flashing neon sign to indicate guests wouldn’t be limited to American breakfast fare that they found unappealing. The strategy was ideal for hotels, which saved money by offering some muffins, fruit, and coffee and calling it a day.

That affordability as well as convenience—pastries and fruit are shelf-stable, requiring no heat or refrigeration to maintain food safety—is a big reason continental breakfasts have endured. It’s also a carryover from the hybrid model of hotel pricing, where American hotels typically folded the cost of meals into one bill and European hotels billed for food separately. By offering a continental breakfast, guests got the best of both worlds. And while Americans were initially aghast at the lack of sausages and pancakes on offer, they’ve since come around to the appeal of a muffin and some orange juice to get their travel day started.

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