WEBVTT - How Does Venus Work? 0:00:01.920 --> 0:00:06.800 Welcome to brain Stuff production of iHeart Radio, Hey brain 0:00:06.840 --> 0:00:10.640 Stuff Lauren Boba Bam here after the moon. Venus is 0:00:10.680 --> 0:00:14.520 the second brightest natural object in the night sky, partially 0:00:14.560 --> 0:00:17.840 because this planet is covered by reflective clouds that naked 0:00:17.880 --> 0:00:21.760 eyes and optical telescopes can't penetrate. With the Venusian surface 0:00:21.800 --> 0:00:24.960 hidden from view, generations of fiction writers used to speculate 0:00:25.000 --> 0:00:29.639 like wild about the mysterious terrain beneath those clouds. For example, 0:00:29.800 --> 0:00:33.040 Tarzan creator Edgar Rice Burrows portrayed Venus as a world 0:00:33.040 --> 0:00:36.600 with lush forests and arboreal cities in four pulp novel. 0:00:37.400 --> 0:00:41.000 But then science intervened. The idea that Venus is habitable 0:00:41.040 --> 0:00:44.520 pretty much imploded during the Cold War. In nine six, 0:00:44.840 --> 0:00:48.240 radio telescope observations show that the planet had surface temperatures 0:00:48.280 --> 0:00:51.599 and excess of six hundred and eighteen degrees fahrenheit that's 0:00:51.640 --> 0:00:56.120 three degrees celsius. And believe it or not, those readings 0:00:56.120 --> 0:00:59.160 were kind of low. We now know the average surface 0:00:59.160 --> 0:01:02.320 temperature on Vena is a blistering eight hundred and sixty 0:01:02.320 --> 0:01:05.759 four degrees fahrenheit or four hundred and sixty two celsius. 0:01:06.240 --> 0:01:08.479 It's the hottest planet in our Solar system. Even though 0:01:08.520 --> 0:01:11.840 mercury is closer to the Sun on the face of Venus, 0:01:11.959 --> 0:01:15.160 the atmospheric pressure is crushing ly extreme, and lead would 0:01:15.160 --> 0:01:18.720 melt into a puddle. But as hellish as this place sounds, 0:01:18.959 --> 0:01:21.840 it actually has a lot in common with Earth. The 0:01:21.880 --> 0:01:24.600 two worlds are quite similar in size. If you were 0:01:24.640 --> 0:01:27.840 to stuff Venus inside our planet a Matroshka doll style, 0:01:28.080 --> 0:01:32.440 it would occupy roughly eight of Earth's total volume. Venus 0:01:32.480 --> 0:01:36.200 has Earth beaten in some key regards, though Earth displays 0:01:36.240 --> 0:01:39.520 a slight midsection bulge, being wider around its equator than 0:01:39.560 --> 0:01:42.959 it is from one pole to the other. Conversely, Venus 0:01:43.000 --> 0:01:47.000 is almost a perfect sphere. What gives well when a 0:01:47.040 --> 0:01:50.160 massive celestial body like a star or planet spins quickly 0:01:50.240 --> 0:01:52.880 around its access centrifugal force will give it a more 0:01:52.960 --> 0:01:56.880 dramatic bulge around its equator. However, Venus has an ultra 0:01:57.000 --> 0:02:00.640 slow rotation speed. It takes the equivalent of two hundred 0:02:00.640 --> 0:02:03.680 and forty three earth days for Venus to complete one 0:02:03.760 --> 0:02:07.120 full rotation around its axis, and only two d and 0:02:07.200 --> 0:02:09.280 twenty five earth days to finish a new lap around 0:02:09.320 --> 0:02:12.560 the Sun. So, in other words, a day on Venus 0:02:12.639 --> 0:02:16.200 lasts longer than a Venetian year does, and get this 0:02:16.600 --> 0:02:21.080 from our self centered perspective, Venus spins backward. Most of 0:02:21.080 --> 0:02:23.840 the planets in the Solar System rotate from west to east. 0:02:24.320 --> 0:02:27.760 Irnus and Venus buck that trend. On those two worlds, 0:02:27.880 --> 0:02:30.160 the sun appears to rise in the west and set 0:02:30.320 --> 0:02:33.519 in the east. Nobody knows how that came to pass. 0:02:33.919 --> 0:02:37.080 Astronomers think Venus used to move in a counterclockwise direction 0:02:37.160 --> 0:02:42.040 like Earth, but at some point its spin might have reversed. Alternatively, 0:02:42.280 --> 0:02:45.440 perhaps the Sun's gravitational influence or a collision with a 0:02:45.520 --> 0:02:48.920 large object caused the entire planet to flip upside down. 0:02:50.160 --> 0:02:53.480 In December of nineteen two, Venus became the first planet 0:02:53.480 --> 0:02:55.839 to get a fly by visit from a man made spacecraft. 0:02:56.360 --> 0:02:59.799 Exploiting a brief window of opportunity, NASA's Mariner two probes 0:02:59.880 --> 0:03:02.639 to need this world up close from distances as near 0:03:02.680 --> 0:03:06.200 as twenty one miles that's about thirty four thousand kilometers. 0:03:06.680 --> 0:03:09.799 The onboard instruments taught us a great deal. Mariner, too, 0:03:09.800 --> 0:03:13.120 confirmed that Venus does not have an Earth like magnetic field, 0:03:13.360 --> 0:03:16.640 and it recorded surface temperatures within the expected range. A 0:03:16.680 --> 0:03:19.640 young Carl Sagan helped design the Mariner to probe. He 0:03:19.720 --> 0:03:22.560 unsuccessfully lobbied to have the spacecraft fitted with a camera 0:03:22.680 --> 0:03:26.320 because close up pictures of Venus might quote answer questions 0:03:26.360 --> 0:03:30.120 that we were too dumb to even pose. By the 0:03:30.160 --> 0:03:33.000 time Mariner Too launched, scientists already knew that there were 0:03:33.080 --> 0:03:36.480 high levels of carbon dioxide in the Venusian atmosphere, and 0:03:36.720 --> 0:03:40.880 that composition should give us pause. Carbon dioxide makes up 0:03:40.920 --> 0:03:45.560 a whopping of Venus's atmosphere. Scientists attribute this to a 0:03:45.640 --> 0:03:49.640 runaway greenhouse effect. Theoretically, the planet used to have a 0:03:49.680 --> 0:03:52.640 more temperate climate that could have remained stable for billions 0:03:52.640 --> 0:03:56.000 of years. Back then, oceans of liquid water may have 0:03:56.080 --> 0:03:59.720 covered its surface, though we don't know for sure. Things 0:04:00.080 --> 0:04:03.480 changed as our growing sun became hotter. Any oceans would 0:04:03.480 --> 0:04:06.440 have evaporated during this time, and astronomers think much of 0:04:06.440 --> 0:04:10.400 the carbon dioxide in Venusian rocks leached out and traveled skyward. 0:04:11.240 --> 0:04:14.320 While the atmosphere changed, it got better at trapping heat, 0:04:14.680 --> 0:04:18.920 creating a vicious cycle that worsened the problem. Inevitably, temperatures 0:04:18.920 --> 0:04:23.200 spiked and stayed. Since our own planet has a major 0:04:23.200 --> 0:04:26.640 greenhouse gas problem, Venus could offer us some important insights 0:04:26.640 --> 0:04:30.200 regarding climate change, but sending probes to explore it has 0:04:30.240 --> 0:04:34.880 always presented major challenges. On Venus, the surface gravity is 0:04:34.920 --> 0:04:37.680 comparable to what you and I experience on Earth. What's 0:04:37.800 --> 0:04:41.400 not comparable is that atmospheric pressure, which is nine two 0:04:41.400 --> 0:04:43.920 times greater on the face of Venus than it is here. 0:04:45.080 --> 0:04:48.200 Faced with extreme temperatures and high pressure, it's no wonder 0:04:48.200 --> 0:04:51.200 that man made objects don't last long in the planet's environment. 0:04:52.240 --> 0:04:55.920 When the Soviet Venera thirteen probe landed on Venus two, 0:04:56.279 --> 0:04:59.159 it stayed intact for a record setting one and twenty 0:04:59.160 --> 0:05:03.159 seven minutes before it was destroyed. Mind you, this wasn't 0:05:03.200 --> 0:05:06.720 the U s s RS first rodeo. Previous Venera spacecrafts 0:05:06.760 --> 0:05:09.560 had successfully visited the planet's atmosphere and touched down on 0:05:09.600 --> 0:05:13.239 its outer crust brief though their visits were these probes 0:05:13.320 --> 0:05:17.320 captured the first ever photographs of the Venusian surface. NASA's 0:05:17.360 --> 0:05:21.520 Magellan spacecraft provided further insights as it mapped of the 0:05:21.520 --> 0:05:26.040 planet's face. All in all, Venus boasts more than sixteen 0:05:26.080 --> 0:05:29.720 thousand volcanoes and volcanic features, but we don't know if 0:05:29.720 --> 0:05:33.400 any of these are still active. Highland plateaus, deep canyons, 0:05:33.440 --> 0:05:37.000 and meteorite impact craters have also been discovered there. Although 0:05:37.120 --> 0:05:39.920 Venus is about four point six billion years old, its 0:05:39.920 --> 0:05:42.440 crust is thought to be much younger, with an estimated 0:05:42.480 --> 0:05:46.640 age of just three to six hundred million years. Venus 0:05:46.680 --> 0:05:49.839 lacks tectonic plates as we know them on Earth. Nonetheless, 0:05:49.920 --> 0:05:54.200 some geologists think that upwellings of magma occasionally recycle sections 0:05:54.240 --> 0:05:57.280 of the crust, long before it was an object of 0:05:57.279 --> 0:06:01.400 scientific study, or of Edgar Rice Burrough's novel, Venus mesmerized 0:06:01.400 --> 0:06:05.239 our ancestors, Bright and beautiful. The cloud adorned planet derives 0:06:05.279 --> 0:06:08.760 its name from the Roman goddess of love. Ancient mathematicians 0:06:08.760 --> 0:06:12.160 mapped its progress across the sky, and Galileo took detailed 0:06:12.200 --> 0:06:16.359 notes about its moonlike phases. Somehow, knowing that Venus is 0:06:16.400 --> 0:06:19.960 a stifling hothouse doesn't diminish its alure. With every new 0:06:19.960 --> 0:06:28.600 discovery inspires curiosity and awe. Today's episode was written by 0:06:28.600 --> 0:06:31.479 Mark Mancini and produced by Tyler Clang. Brain Stuff is 0:06:31.480 --> 0:06:33.599 a production of I Heart Radio's How Stuff Works. For 0:06:33.640 --> 0:06:36.560 more in this and lots of other hot topics, visit 0:06:36.600 --> 0:06:39.159 our home planet, How stuff works dot com and for 0:06:39.200 --> 0:06:41.880 more podcast my Heart Radio, visit the iHeart Radio app, 0:06:41.960 --> 0:06:44.599 Apple Podcasts, or wherever you listen to your favorite shows.