Speaker 1: Welcome to brain Stuff production of iHeart Radio, Hey brain
Speaker 1: Stuff Lauren Boba Bam here after the moon. Venus is
Speaker 1: the second brightest natural object in the night sky, partially
Speaker 1: because this planet is covered by reflective clouds that naked
Speaker 1: eyes and optical telescopes can't penetrate. With the Venusian surface
Speaker 1: hidden from view, generations of fiction writers used to speculate
Speaker 1: like wild about the mysterious terrain beneath those clouds. For example,
Speaker 1: Tarzan creator Edgar Rice Burrows portrayed Venus as a world
Speaker 1: with lush forests and arboreal cities in four pulp novel.
Speaker 1: But then science intervened. The idea that Venus is habitable
Speaker 1: pretty much imploded during the Cold War. In nine six,
Speaker 1: radio telescope observations show that the planet had surface temperatures
Speaker 1: and excess of six hundred and eighteen degrees fahrenheit that's
Speaker 1: three degrees celsius. And believe it or not, those readings
Speaker 1: were kind of low. We now know the average surface
Speaker 1: temperature on Vena is a blistering eight hundred and sixty
Speaker 1: four degrees fahrenheit or four hundred and sixty two celsius.
Speaker 1: It's the hottest planet in our Solar system. Even though
Speaker 1: mercury is closer to the Sun on the face of Venus,
Speaker 1: the atmospheric pressure is crushing ly extreme, and lead would
Speaker 1: melt into a puddle. But as hellish as this place sounds,
Speaker 1: it actually has a lot in common with Earth. The
Speaker 1: two worlds are quite similar in size. If you were
Speaker 1: to stuff Venus inside our planet a Matroshka doll style,
Speaker 1: it would occupy roughly eight of Earth's total volume. Venus
Speaker 1: has Earth beaten in some key regards, though Earth displays
Speaker 1: a slight midsection bulge, being wider around its equator than
Speaker 1: it is from one pole to the other. Conversely, Venus
Speaker 1: is almost a perfect sphere. What gives well when a
Speaker 1: massive celestial body like a star or planet spins quickly
Speaker 1: around its access centrifugal force will give it a more
Speaker 1: dramatic bulge around its equator. However, Venus has an ultra
Speaker 1: slow rotation speed. It takes the equivalent of two hundred
Speaker 1: and forty three earth days for Venus to complete one
Speaker 1: full rotation around its axis, and only two d and
Speaker 1: twenty five earth days to finish a new lap around
Speaker 1: the Sun. So, in other words, a day on Venus
Speaker 1: lasts longer than a Venetian year does, and get this
Speaker 1: from our self centered perspective, Venus spins backward. Most of
Speaker 1: the planets in the Solar System rotate from west to east.
Speaker 1: Irnus and Venus buck that trend. On those two worlds,
Speaker 1: the sun appears to rise in the west and set
Speaker 1: in the east. Nobody knows how that came to pass.
Speaker 1: Astronomers think Venus used to move in a counterclockwise direction
Speaker 1: like Earth, but at some point its spin might have reversed. Alternatively,
Speaker 1: perhaps the Sun's gravitational influence or a collision with a
Speaker 1: large object caused the entire planet to flip upside down.
Speaker 1: In December of nineteen two, Venus became the first planet
Speaker 1: to get a fly by visit from a man made spacecraft.
Speaker 1: Exploiting a brief window of opportunity, NASA's Mariner two probes
Speaker 1: to need this world up close from distances as near
Speaker 1: as twenty one miles that's about thirty four thousand kilometers.
Speaker 1: The onboard instruments taught us a great deal. Mariner, too,
Speaker 1: confirmed that Venus does not have an Earth like magnetic field,
Speaker 1: and it recorded surface temperatures within the expected range. A
Speaker 1: young Carl Sagan helped design the Mariner to probe. He
Speaker 1: unsuccessfully lobbied to have the spacecraft fitted with a camera
Speaker 1: because close up pictures of Venus might quote answer questions
Speaker 1: that we were too dumb to even pose. By the
Speaker 1: time Mariner Too launched, scientists already knew that there were
Speaker 1: high levels of carbon dioxide in the Venusian atmosphere, and
Speaker 1: that composition should give us pause. Carbon dioxide makes up
Speaker 1: a whopping of Venus's atmosphere. Scientists attribute this to a
Speaker 1: runaway greenhouse effect. Theoretically, the planet used to have a
Speaker 1: more temperate climate that could have remained stable for billions
Speaker 1: of years. Back then, oceans of liquid water may have
Speaker 1: covered its surface, though we don't know for sure. Things
Speaker 1: changed as our growing sun became hotter. Any oceans would
Speaker 1: have evaporated during this time, and astronomers think much of
Speaker 1: the carbon dioxide in Venusian rocks leached out and traveled skyward.
Speaker 1: While the atmosphere changed, it got better at trapping heat,
Speaker 1: creating a vicious cycle that worsened the problem. Inevitably, temperatures
Speaker 1: spiked and stayed. Since our own planet has a major
Speaker 1: greenhouse gas problem, Venus could offer us some important insights
Speaker 1: regarding climate change, but sending probes to explore it has
Speaker 1: always presented major challenges. On Venus, the surface gravity is
Speaker 1: comparable to what you and I experience on Earth. What's
Speaker 1: not comparable is that atmospheric pressure, which is nine two
Speaker 1: times greater on the face of Venus than it is here.
Speaker 1: Faced with extreme temperatures and high pressure, it's no wonder
Speaker 1: that man made objects don't last long in the planet's environment.
Speaker 1: When the Soviet Venera thirteen probe landed on Venus two,
Speaker 1: it stayed intact for a record setting one and twenty
Speaker 1: seven minutes before it was destroyed. Mind you, this wasn't
Speaker 1: the U s s RS first rodeo. Previous Venera spacecrafts
Speaker 1: had successfully visited the planet's atmosphere and touched down on
Speaker 1: its outer crust brief though their visits were these probes
Speaker 1: captured the first ever photographs of the Venusian surface. NASA's
Speaker 1: Magellan spacecraft provided further insights as it mapped of the
Speaker 1: planet's face. All in all, Venus boasts more than sixteen
Speaker 1: thousand volcanoes and volcanic features, but we don't know if
Speaker 1: any of these are still active. Highland plateaus, deep canyons,
Speaker 1: and meteorite impact craters have also been discovered there. Although
Speaker 1: Venus is about four point six billion years old, its
Speaker 1: crust is thought to be much younger, with an estimated
Speaker 1: age of just three to six hundred million years. Venus
Speaker 1: lacks tectonic plates as we know them on Earth. Nonetheless,
Speaker 1: some geologists think that upwellings of magma occasionally recycle sections
Speaker 1: of the crust, long before it was an object of
Speaker 1: scientific study, or of Edgar Rice Burrough's novel, Venus mesmerized
Speaker 1: our ancestors, Bright and beautiful. The cloud adorned planet derives
Speaker 1: its name from the Roman goddess of love. Ancient mathematicians
Speaker 1: mapped its progress across the sky, and Galileo took detailed
Speaker 1: notes about its moonlike phases. Somehow, knowing that Venus is
Speaker 1: a stifling hothouse doesn't diminish its alure. With every new
Speaker 1: discovery inspires curiosity and awe. Today's episode was written by
Speaker 1: Mark Mancini and produced by Tyler Clang. Brain Stuff is
Speaker 1: a production of I Heart Radio's How Stuff Works. For
Speaker 1: more in this and lots of other hot topics, visit
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