1 00:00:01,920 --> 00:00:06,800 Speaker 1: Welcome to brain Stuff production of iHeart Radio, Hey brain 2 00:00:06,840 --> 00:00:10,640 Speaker 1: Stuff Lauren Boba Bam here after the moon. Venus is 3 00:00:10,680 --> 00:00:14,520 Speaker 1: the second brightest natural object in the night sky, partially 4 00:00:14,560 --> 00:00:17,840 Speaker 1: because this planet is covered by reflective clouds that naked 5 00:00:17,880 --> 00:00:21,760 Speaker 1: eyes and optical telescopes can't penetrate. With the Venusian surface 6 00:00:21,800 --> 00:00:24,960 Speaker 1: hidden from view, generations of fiction writers used to speculate 7 00:00:25,000 --> 00:00:29,639 Speaker 1: like wild about the mysterious terrain beneath those clouds. For example, 8 00:00:29,800 --> 00:00:33,040 Speaker 1: Tarzan creator Edgar Rice Burrows portrayed Venus as a world 9 00:00:33,040 --> 00:00:36,600 Speaker 1: with lush forests and arboreal cities in four pulp novel. 10 00:00:37,400 --> 00:00:41,000 Speaker 1: But then science intervened. The idea that Venus is habitable 11 00:00:41,040 --> 00:00:44,520 Speaker 1: pretty much imploded during the Cold War. In nine six, 12 00:00:44,840 --> 00:00:48,240 Speaker 1: radio telescope observations show that the planet had surface temperatures 13 00:00:48,280 --> 00:00:51,599 Speaker 1: and excess of six hundred and eighteen degrees fahrenheit that's 14 00:00:51,640 --> 00:00:56,120 Speaker 1: three degrees celsius. And believe it or not, those readings 15 00:00:56,120 --> 00:00:59,160 Speaker 1: were kind of low. We now know the average surface 16 00:00:59,160 --> 00:01:02,320 Speaker 1: temperature on Vena is a blistering eight hundred and sixty 17 00:01:02,320 --> 00:01:05,759 Speaker 1: four degrees fahrenheit or four hundred and sixty two celsius. 18 00:01:06,240 --> 00:01:08,479 Speaker 1: It's the hottest planet in our Solar system. Even though 19 00:01:08,520 --> 00:01:11,840 Speaker 1: mercury is closer to the Sun on the face of Venus, 20 00:01:11,959 --> 00:01:15,160 Speaker 1: the atmospheric pressure is crushing ly extreme, and lead would 21 00:01:15,160 --> 00:01:18,720 Speaker 1: melt into a puddle. But as hellish as this place sounds, 22 00:01:18,959 --> 00:01:21,840 Speaker 1: it actually has a lot in common with Earth. The 23 00:01:21,880 --> 00:01:24,600 Speaker 1: two worlds are quite similar in size. If you were 24 00:01:24,640 --> 00:01:27,840 Speaker 1: to stuff Venus inside our planet a Matroshka doll style, 25 00:01:28,080 --> 00:01:32,440 Speaker 1: it would occupy roughly eight of Earth's total volume. Venus 26 00:01:32,480 --> 00:01:36,200 Speaker 1: has Earth beaten in some key regards, though Earth displays 27 00:01:36,240 --> 00:01:39,520 Speaker 1: a slight midsection bulge, being wider around its equator than 28 00:01:39,560 --> 00:01:42,959 Speaker 1: it is from one pole to the other. Conversely, Venus 29 00:01:43,000 --> 00:01:47,000 Speaker 1: is almost a perfect sphere. What gives well when a 30 00:01:47,040 --> 00:01:50,160 Speaker 1: massive celestial body like a star or planet spins quickly 31 00:01:50,240 --> 00:01:52,880 Speaker 1: around its access centrifugal force will give it a more 32 00:01:52,960 --> 00:01:56,880 Speaker 1: dramatic bulge around its equator. However, Venus has an ultra 33 00:01:57,000 --> 00:02:00,640 Speaker 1: slow rotation speed. It takes the equivalent of two hundred 34 00:02:00,640 --> 00:02:03,680 Speaker 1: and forty three earth days for Venus to complete one 35 00:02:03,760 --> 00:02:07,120 Speaker 1: full rotation around its axis, and only two d and 36 00:02:07,200 --> 00:02:09,280 Speaker 1: twenty five earth days to finish a new lap around 37 00:02:09,320 --> 00:02:12,560 Speaker 1: the Sun. So, in other words, a day on Venus 38 00:02:12,639 --> 00:02:16,200 Speaker 1: lasts longer than a Venetian year does, and get this 39 00:02:16,600 --> 00:02:21,080 Speaker 1: from our self centered perspective, Venus spins backward. Most of 40 00:02:21,080 --> 00:02:23,840 Speaker 1: the planets in the Solar System rotate from west to east. 41 00:02:24,320 --> 00:02:27,760 Speaker 1: Irnus and Venus buck that trend. On those two worlds, 42 00:02:27,880 --> 00:02:30,160 Speaker 1: the sun appears to rise in the west and set 43 00:02:30,320 --> 00:02:33,519 Speaker 1: in the east. Nobody knows how that came to pass. 44 00:02:33,919 --> 00:02:37,080 Speaker 1: Astronomers think Venus used to move in a counterclockwise direction 45 00:02:37,160 --> 00:02:42,040 Speaker 1: like Earth, but at some point its spin might have reversed. Alternatively, 46 00:02:42,280 --> 00:02:45,440 Speaker 1: perhaps the Sun's gravitational influence or a collision with a 47 00:02:45,520 --> 00:02:48,920 Speaker 1: large object caused the entire planet to flip upside down. 48 00:02:50,160 --> 00:02:53,480 Speaker 1: In December of nineteen two, Venus became the first planet 49 00:02:53,480 --> 00:02:55,839 Speaker 1: to get a fly by visit from a man made spacecraft. 50 00:02:56,360 --> 00:02:59,799 Speaker 1: Exploiting a brief window of opportunity, NASA's Mariner two probes 51 00:02:59,880 --> 00:03:02,639 Speaker 1: to need this world up close from distances as near 52 00:03:02,680 --> 00:03:06,200 Speaker 1: as twenty one miles that's about thirty four thousand kilometers. 53 00:03:06,680 --> 00:03:09,799 Speaker 1: The onboard instruments taught us a great deal. Mariner, too, 54 00:03:09,800 --> 00:03:13,120 Speaker 1: confirmed that Venus does not have an Earth like magnetic field, 55 00:03:13,360 --> 00:03:16,640 Speaker 1: and it recorded surface temperatures within the expected range. A 56 00:03:16,680 --> 00:03:19,640 Speaker 1: young Carl Sagan helped design the Mariner to probe. He 57 00:03:19,720 --> 00:03:22,560 Speaker 1: unsuccessfully lobbied to have the spacecraft fitted with a camera 58 00:03:22,680 --> 00:03:26,320 Speaker 1: because close up pictures of Venus might quote answer questions 59 00:03:26,360 --> 00:03:30,120 Speaker 1: that we were too dumb to even pose. By the 60 00:03:30,160 --> 00:03:33,000 Speaker 1: time Mariner Too launched, scientists already knew that there were 61 00:03:33,080 --> 00:03:36,480 Speaker 1: high levels of carbon dioxide in the Venusian atmosphere, and 62 00:03:36,720 --> 00:03:40,880 Speaker 1: that composition should give us pause. Carbon dioxide makes up 63 00:03:40,920 --> 00:03:45,560 Speaker 1: a whopping of Venus's atmosphere. Scientists attribute this to a 64 00:03:45,640 --> 00:03:49,640 Speaker 1: runaway greenhouse effect. Theoretically, the planet used to have a 65 00:03:49,680 --> 00:03:52,640 Speaker 1: more temperate climate that could have remained stable for billions 66 00:03:52,640 --> 00:03:56,000 Speaker 1: of years. Back then, oceans of liquid water may have 67 00:03:56,080 --> 00:03:59,720 Speaker 1: covered its surface, though we don't know for sure. Things 68 00:04:00,080 --> 00:04:03,480 Speaker 1: changed as our growing sun became hotter. Any oceans would 69 00:04:03,480 --> 00:04:06,440 Speaker 1: have evaporated during this time, and astronomers think much of 70 00:04:06,440 --> 00:04:10,400 Speaker 1: the carbon dioxide in Venusian rocks leached out and traveled skyward. 71 00:04:11,240 --> 00:04:14,320 Speaker 1: While the atmosphere changed, it got better at trapping heat, 72 00:04:14,680 --> 00:04:18,920 Speaker 1: creating a vicious cycle that worsened the problem. Inevitably, temperatures 73 00:04:18,920 --> 00:04:23,200 Speaker 1: spiked and stayed. Since our own planet has a major 74 00:04:23,200 --> 00:04:26,640 Speaker 1: greenhouse gas problem, Venus could offer us some important insights 75 00:04:26,640 --> 00:04:30,200 Speaker 1: regarding climate change, but sending probes to explore it has 76 00:04:30,240 --> 00:04:34,880 Speaker 1: always presented major challenges. On Venus, the surface gravity is 77 00:04:34,920 --> 00:04:37,680 Speaker 1: comparable to what you and I experience on Earth. What's 78 00:04:37,800 --> 00:04:41,400 Speaker 1: not comparable is that atmospheric pressure, which is nine two 79 00:04:41,400 --> 00:04:43,920 Speaker 1: times greater on the face of Venus than it is here. 80 00:04:45,080 --> 00:04:48,200 Speaker 1: Faced with extreme temperatures and high pressure, it's no wonder 81 00:04:48,200 --> 00:04:51,200 Speaker 1: that man made objects don't last long in the planet's environment. 82 00:04:52,240 --> 00:04:55,920 Speaker 1: When the Soviet Venera thirteen probe landed on Venus two, 83 00:04:56,279 --> 00:04:59,159 Speaker 1: it stayed intact for a record setting one and twenty 84 00:04:59,160 --> 00:05:03,159 Speaker 1: seven minutes before it was destroyed. Mind you, this wasn't 85 00:05:03,200 --> 00:05:06,720 Speaker 1: the U s s RS first rodeo. Previous Venera spacecrafts 86 00:05:06,760 --> 00:05:09,560 Speaker 1: had successfully visited the planet's atmosphere and touched down on 87 00:05:09,600 --> 00:05:13,239 Speaker 1: its outer crust brief though their visits were these probes 88 00:05:13,320 --> 00:05:17,320 Speaker 1: captured the first ever photographs of the Venusian surface. NASA's 89 00:05:17,360 --> 00:05:21,520 Speaker 1: Magellan spacecraft provided further insights as it mapped of the 90 00:05:21,520 --> 00:05:26,040 Speaker 1: planet's face. All in all, Venus boasts more than sixteen 91 00:05:26,080 --> 00:05:29,720 Speaker 1: thousand volcanoes and volcanic features, but we don't know if 92 00:05:29,720 --> 00:05:33,400 Speaker 1: any of these are still active. Highland plateaus, deep canyons, 93 00:05:33,440 --> 00:05:37,000 Speaker 1: and meteorite impact craters have also been discovered there. Although 94 00:05:37,120 --> 00:05:39,920 Speaker 1: Venus is about four point six billion years old, its 95 00:05:39,920 --> 00:05:42,440 Speaker 1: crust is thought to be much younger, with an estimated 96 00:05:42,480 --> 00:05:46,640 Speaker 1: age of just three to six hundred million years. Venus 97 00:05:46,680 --> 00:05:49,839 Speaker 1: lacks tectonic plates as we know them on Earth. Nonetheless, 98 00:05:49,920 --> 00:05:54,200 Speaker 1: some geologists think that upwellings of magma occasionally recycle sections 99 00:05:54,240 --> 00:05:57,280 Speaker 1: of the crust, long before it was an object of 100 00:05:57,279 --> 00:06:01,400 Speaker 1: scientific study, or of Edgar Rice Burrough's novel, Venus mesmerized 101 00:06:01,400 --> 00:06:05,239 Speaker 1: our ancestors, Bright and beautiful. The cloud adorned planet derives 102 00:06:05,279 --> 00:06:08,760 Speaker 1: its name from the Roman goddess of love. Ancient mathematicians 103 00:06:08,760 --> 00:06:12,160 Speaker 1: mapped its progress across the sky, and Galileo took detailed 104 00:06:12,200 --> 00:06:16,359 Speaker 1: notes about its moonlike phases. Somehow, knowing that Venus is 105 00:06:16,400 --> 00:06:19,960 Speaker 1: a stifling hothouse doesn't diminish its alure. With every new 106 00:06:19,960 --> 00:06:28,600 Speaker 1: discovery inspires curiosity and awe. Today's episode was written by 107 00:06:28,600 --> 00:06:31,479 Speaker 1: Mark Mancini and produced by Tyler Clang. Brain Stuff is 108 00:06:31,480 --> 00:06:33,599 Speaker 1: a production of I Heart Radio's How Stuff Works. For 109 00:06:33,640 --> 00:06:36,560 Speaker 1: more in this and lots of other hot topics, visit 110 00:06:36,600 --> 00:06:39,159 Speaker 1: our home planet, How stuff works dot com and for 111 00:06:39,200 --> 00:06:41,880 Speaker 1: more podcast my Heart Radio, visit the iHeart Radio app, 112 00:06:41,960 --> 00:06:44,599 Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.