Speaker 1: Welcome to brain Stuff, a production of iHeart Radio, Hey
Speaker 1: brain Stuff Lauren bogebam Here. Old Faithful used to have
Speaker 1: a less than modest nickname Eternity's time Piece. Since at
Speaker 1: least the late eighteen hundreds, this wyoming cone geyser has
Speaker 1: wowed spectators with its predictable eruptions. You can see the
Speaker 1: landmark for yourself in Yellowstone National Park, home to over
Speaker 1: five hundred geysers. More than one hundred and fifty of
Speaker 1: these water spurting marvels, including Old Faithful, occupy the park's
Speaker 1: upper geyser basin. So named in eighteen seventy because it's
Speaker 1: spouted at regular intervals, Old Faithful gets more fanfair than
Speaker 1: any other geothermal attraction in the world. Visited by presidents
Speaker 1: and immortalized by artists, the geyser spouts about seventeen times
Speaker 1: a day. Countdown clocks tell gathering tourists when too ready
Speaker 1: their cameras for the next waterworks show. You see. There's
Speaker 1: a simple formula rangers used to estimate how much time
Speaker 1: will likely elapse between any two eruptions of Old Faithful.
Speaker 1: According to the National Park Service, about of these eruption
Speaker 1: predictions are accurate within a window of plus or minus
Speaker 1: ten minutes. That's a solid track record, but Old Faithful
Speaker 1: still isn't something you'd want to set your watch by.
Speaker 1: Five decades of observation have revealed that the geyser is changing.
Speaker 1: Since nine, the average interval between Old Faithful's eruptions has
Speaker 1: gotten longer, and while most of the actual eruptions which
Speaker 1: occurred back then were rather brief, this is no longer
Speaker 1: the case. But we spoke via email with Sin May Wu,
Speaker 1: a geologist at the University of Utah who studied the
Speaker 1: physics of geyser's and related structures. She said geysers are
Speaker 1: rare because they require very unique geologic conditions, a persistent
Speaker 1: heat source, abundant water supply from groundwater systems, and a
Speaker 1: porous or fractured medium that allows fluid migration and heat
Speaker 1: transfer within. Usually the heat comes from magma, a liquid
Speaker 1: or semi liquid rock found below Earth's crust, which is
Speaker 1: called lava once it bursts onto the surface. Yellow Stone
Speaker 1: is positioned over two magma chambers, including a nice long
Speaker 1: one that's just three to ten miles underground that's five
Speaker 1: to seventeen kilometers. Their maker was a localized swell of
Speaker 1: abnormally hot material beneath the crust, classified as a mantle plume.
Speaker 1: It's the reason why Yellowstone has the world's largest geyser collection.
Speaker 1: The chambers warm up subterranean reservoirs of liquid groundwater. Although
Speaker 1: the physics here aren't entirely settled, we do know that
Speaker 1: some of this water gets superheated. That means it's temperature
Speaker 1: climbs above and beyond water's normal boiling point. Since this
Speaker 1: water is held in tight corridors, it's got nowhere else
Speaker 1: to go at first, Bearing down on the superheated liquid
Speaker 1: is a combination of overhanging rock and colder water. Add
Speaker 1: cramped quarters to the mix, and you've got a recipe
Speaker 1: for high pressure. But the pressure doesn't last for her.
Speaker 1: In a geyser like Old Faithful, hyperactive steam bubbles eventually
Speaker 1: push a small percentage of the groundwater through a narrow
Speaker 1: opening at the surface. Just like that, the pressure decreases
Speaker 1: and sets off an explosion of hot water and steam.
Speaker 1: If you're wise, you'll give Old Faithful a wide berth.
Speaker 1: Visitors can safely watch the geyser erupt from a boardwalk
Speaker 1: maintained by Yellowstone Venture off that path and you might
Speaker 1: be on the hook for six months in prison and
Speaker 1: a five thousand dollar fine. And besides, getting too close
Speaker 1: to hydrothermal features like geysers or hot springs isn't a
Speaker 1: cool idea. When Old Faithful goes off, the water temperature
Speaker 1: around its vent can hit two hundred and four degrees
Speaker 1: fahrenheit that's ninety six celsius. Meanwhile, the steam gets even hotter,
Speaker 1: sometimes exceeding three hundred and fifty degrees fahrenheit or hundred
Speaker 1: and seventy seven celsius viewed from an appropriate distance, Old
Speaker 1: Faithful's eruptions are thrilling spectacles, even if you've seen one before.
Speaker 1: You might want to revisit the geyser someday. Because certain
Speaker 1: eruptions last longer than others, will explained that Old Faithful
Speaker 1: isn't as predictable as it once seemed. There are two
Speaker 1: different categories of gaps between eruptions and of eruptions themselves.
Speaker 1: An eruption that begins and ends and under two and
Speaker 1: a half minutes is considered short. Others are longer. After
Speaker 1: a short eruption, there will be an intermission of sixty
Speaker 1: two sixty five minutes before the geyser spouts again. Yet
Speaker 1: Old Faithful will reliably take a break of around ninety
Speaker 1: two minutes once a long eruption subsides. Over the past
Speaker 1: fifty years, long eruptions at Old Faithful have become the norm.
Speaker 1: Short ones still occur, but they are rarer than they
Speaker 1: used to be, and no one is entirely sure why.
Speaker 1: While the mystery is unresolved, some geologists blame recent earthquakes
Speaker 1: for this changing schedule. The geyser's source is another riddle.
Speaker 1: Scientists haven't determined where Old Faithful gets its water supply,
Speaker 1: though in a study, Wu and five call leagues revealed
Speaker 1: an important clue. Using seismic wave sensors, they found a
Speaker 1: natural reservoir below the historic Old Faithful Inn, which stands
Speaker 1: southwest of the geyser. Wu said that body is interpreted
Speaker 1: to be a highly fractured and saturated area that we
Speaker 1: think provides fluids as a source to Old Faithful. Plumbing
Speaker 1: questions and bimodal eruptions aside, Old Faithful is indeed more
Speaker 1: Faithful than some of its counterparts. It's time we introduced
Speaker 1: the steamboat geyser, another Yellowstone resident that happens to be
Speaker 1: the world's tallest active geyser, emitting jets of water three
Speaker 1: hundred to four hundred feet into the sky above that's
Speaker 1: about nine and twenty but lu said it is very
Speaker 1: unpredictable and has gone decades between eruptions. The last eruption
Speaker 1: before March was in September. She added, however, that the
Speaker 1: blow up quote began an unprecedented active phase. The Steamboat
Speaker 1: geyser has erupted a total of eighty five times since then,
Speaker 1: with the last eruption occurring February one. We still don't
Speaker 1: know what initiates this act of phase, what controls its
Speaker 1: eruptive behavior, and what the geometry looks like, so keep
Speaker 1: an eye on the headlines. Perhaps we'll see some heated
Speaker 1: arguments about these topics in the near future. Today's episode
Speaker 1: was written by Mark Bancini and produced by Tyler Clang.
Speaker 1: For more on this and lots of other active topics,
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