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Speaker 1: Welcome to brain Stuff, a production of I Heart Radio. Hey,

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Speaker 1: brain Stuff, Lauren Bogelbaum Here. Unless you're a pilot or

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Speaker 1: a member of the Justice League, anything that can travel

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Speaker 1: at seven and seventy miles per hour or about one

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Speaker 1: hundred kilometers per hour might seem pretty darn fast on

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Speaker 1: a lukewarm day when atmospheric conditions are normal. That's the

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Speaker 1: approximate speed of sound at Earth's sea level, but the

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Speaker 1: wind speeds on Neptune can put this figure to shame.

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Speaker 1: Some neptune and winds have been clocked it faster than

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Speaker 1: one thousand, two hundred miles or two thousand kilometers per hour.

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Speaker 1: To date, these are the fastest winds recorded anywhere in

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Speaker 1: the Solar System. Neptune's location makes them all the more interesting.

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Speaker 1: Here on Earth, the Sun's energy is what drives our winds,

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Speaker 1: Yet Neptune is the eighth planet in the Solar System,

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Speaker 1: about thirty times farther away from the Sun than we are.

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Speaker 1: The gap between Neptune and our star is a staggering

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Speaker 1: two point eight billion miles or four point five billion

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Speaker 1: kilometers wide. Due to this vast divide, Neptune gets relatively

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Speaker 1: little solar energy so one might expect it to have

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Speaker 1: weak or non existent winds. The fact that the opposite

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Speaker 1: is true reflects the dynamic and mysterious composition of this

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Speaker 1: truly alien world. Astronomers used to divide the planets into

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Speaker 1: two broad categories. The first, called the terrestrial planets, included Mercury, Earth, Venus,

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Speaker 1: and Mars. All four bodies mostly consist of metals or

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Speaker 1: silicate rocks, and they've got solid outer surfaces. Before the

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Speaker 1: nineteen nineties, Jupiter, Saturn, Uranus, and Neptune were lumped together

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Speaker 1: into the second group, the gas giants. Giant is certainly

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Speaker 1: an appropriate label. Jupiter is easily the biggest planet in

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Speaker 1: our Solar system, but Neptune isn't doing too bad for itself.

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Speaker 1: It has a radius of fifteen thousand, three hundred miles,

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Speaker 1: which is about twenty four thousand, six hundred kilometers, making

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Speaker 1: it four times wider than Earth. By the turn of

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Speaker 1: the twenty first century, however, scientists realized that half of

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Speaker 1: these alleged gas giants are fundamentally different from the other half. True,

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Speaker 1: all four bodies lack solid exteriors, but Jupiter and Saturn

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Speaker 1: are predominantly made of hydrogen and helium gas. The same

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Speaker 1: cannot be said of Uranus or Neptune, whose major components

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Speaker 1: are actually heavier elements Beneath a sparse outer layer of helium, hydrogen,

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Speaker 1: and methane. Both worlds have a thick mantle. This layer

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Speaker 1: is loaded with slushy, semi frozen water, ammonia, and methane.

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Speaker 1: Further down, each planet's got an inner core that might

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Speaker 1: be rocky and approximately Earth sized. So today Uranus and

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Speaker 1: Neptune are no longer considered gas giants. Instead, they've been

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Speaker 1: switched to a third category of planets that astronomers call

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Speaker 1: ice giants. You wouldn't mistake one ice giant for the other,

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Speaker 1: though Uranus looks pale blue green to our eyes, whereas

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Speaker 1: Neptune has a deeper royal blue complexion. Both planets contain

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Speaker 1: atmospheric clouds of methane, which simultaneously absorb red light waves

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Speaker 1: and reflect blue ones. This is what gives the two

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Speaker 1: ice giants their bluish color schemes, but it doesn't explain

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Speaker 1: why Neptune is visibly darker in hue. Perhaps there's a

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Speaker 1: mystery ingredient hanging out in the Neptunian atmosphere. However, below

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Speaker 1: their respective atmospheres. Scientists theorize that high heat and pressure

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Speaker 1: forge diamonds, which presumably come raining down out of those

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Speaker 1: methane clouds. But here's another key distinction. Urinus doesn't release

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Speaker 1: much excess heat into space, yet Neptune, like Jupiter and Saturn,

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Speaker 1: emits more energy than it receives from the Sun. Even so,

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Speaker 1: Neptune is considered the Solar System's coldest planet. In some

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Speaker 1: parts of the outer atmosphere, temperatures are liable to hit

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Speaker 1: negative two hundred and eighteen degrees celsius, which is a

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Speaker 1: negative three and sixty degrees fahrenheit. Maybe that helps account

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Speaker 1: for Neptune's ultra fast wind speeds. The atmospheric chill is

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Speaker 1: thought to reduce friction, allowing winds to zip around more freely.

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Speaker 1: Speaking of weather patterns, when the Voyager to spacecraft visited

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Speaker 1: Neptune in nine, it photographed an oval shaped storm some

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Speaker 1: eight thousand miles or thirteen thousand kilometers across, nicknamed the

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Speaker 1: Great Dark Spot. It vanished by the time the Hubble

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Speaker 1: space telescope took a new round of pictures into altogether

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Speaker 1: half a dozen Neptunean storm systems of this kind have

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Speaker 1: been documented. Research published in twenty nineteen indicates the storm's

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Speaker 1: last for about two to six years apiece, compared to

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Speaker 1: Jupiter's Great Red Spot, a tempest that's been going strong

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Speaker 1: since at least the year eighteen thirty. This is a

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Speaker 1: fairly short lifespan. Lots of interesting things are happening above

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Speaker 1: Neptune as well. The ice giant has fourteen known moons,

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Speaker 1: including one that wasn't discovered until this newcomer. Is named

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Speaker 1: Hippocamp in honor of an aquatic beast from Greek mythology.

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Speaker 1: Neptune borrows its own name from the Roman god of

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Speaker 1: the sea. For that reason, astronomers like to name the

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Speaker 1: planets moons after mythic characters with ties to this deity,

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Speaker 1: his Greek counterpart, Poseidon, or the ocean in general. In mythology,

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Speaker 1: one of Poseidon's sons was the trumpet blowing merman. Triton,

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Speaker 1: his namesake moon, is Neptune's largest, at one thousand, seven

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Speaker 1: hundred miles that's kilometers in diameter, It's bigger than the

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Speaker 1: dwarf planet Pluto. Triton is also the only large moon

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Speaker 1: in the entire Solar System with a retrograde orbit. When

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Speaker 1: it circles Neptune, it moves in the opposite direction of

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Speaker 1: the planet's spin. To add further intrigue, Triton has active Geyser's,

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Speaker 1: a rarity in our cosmic neighborhood. Over time, Neptune might

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Speaker 1: have lost a few satellites. Along with Jupiter, Saturn, and Uranus,

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Speaker 1: the planet has its own personal ring system. Astronomers have

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Speaker 1: identified five main rings own Neptune, and just beyond these

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Speaker 1: lie some orbiting clumps of dusty material, dark and faint.

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Speaker 1: The rings of Neptune are presumed to be younger than

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Speaker 1: Uranus is. According to Universe Today, they might be the

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Speaker 1: remains of a moon that was somehow destroyed. Unlike every

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Speaker 1: other planet in our solar system, Neptune is never visible

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Speaker 1: to the naked eye. Yet when it was first spotted

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Speaker 1: via telescope in the year eighteen forty six, the discovery

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Speaker 1: didn't come as a surprise. Keen observers had noticed certain

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Speaker 1: irregularities in Uranus's orbit. As the seventh planet moved around

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Speaker 1: the Sun, it was deviating from its anticipated pathway. So

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Speaker 1: in the early eighteenth century, mathematicians reasoned that a large

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Speaker 1: celestial body must be gravitationally tugging on Uranus, and they

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Speaker 1: were right. Neptune was the culprit. The existence of this

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Speaker 1: azure world, with its savage winds and disappearing storms, was

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Speaker 1: predicted by math students. Let that fact inspire you when

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Speaker 1: those math tests roll around. Today's episode was written by

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Speaker 1: Mark Mancini and produced by Tyler Clang. For more on

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Speaker 1: this and lots of other topics, visit how stuff works

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Speaker 1: dot com. Brain Stuff is production of I Heart Radio.

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