Everything Everywhere Daily: History, Science, Geography & More - Venus

Starting point is 00:00:00 As long as humans have looked up into the sky, they noticed something. There was an unusually bright star that would show up in the early morning or the early evening. This star was one of the few points of light in the sky that moved. These moving lights were dubbed planets, and the one that appeared in the morning and evening was actually thought to be two different ones. Today, we know much more about that moving star in the sky, and found that it's one of the most dangerous places in the solar system. Learn more about Venus, the second planet from the sun.

Starting point is 00:00:28 on this episode of Everything Everywhere Daily. Do you ever climb into bed ready to sleep only to have your mind start racing the moment your head hits the pillow? Thoughts bouncing around, replaying the day, or jumping ahead to tomorrow? That is exactly why Catherine Nikolai created Nothing Much Happens. Each episode is a gentle, cozy bedtime story where, well, nothing much happens. No drama, no tension, nothing you need to follow closely. Just soft narration, calming repetition, and soothing sensory details designed to help your mind slow down

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Starting point is 00:01:36 To start any discussion on Venus, it should probably begin with why Venus is known as the morning star or the evening star. Venus is closer to the sun than the Earth. If you can, imagine two circles to represent the orbital paths of the Earth and Venus, one inside the other. If you draw a line from any point on the outer circle to any point on the inner circle, it's going to have to be somewhat close to the sun. Hence, an observer on Earth is never going to be able to see Venus at midnight because it has an orbit closer to the sun. And the same holds true with Mercury, but even more so because it's even closer to the Sun than Venus. Because Venus is much larger than Mercury from our vantage point on Earth, it means that Venus is the second brightest object in the night sky after the moon.

Starting point is 00:02:20 Because observing Venus meant observing it during a very short window in the morning or evening, we didn't know as much about it as we did for other planets such as Mars, which we could observe in the middle of the night, with longer exposures. As it turns out, at least on paper, Venus is the most similar planet to the Earth in our solar system. Venus is a rocky planet, about 70% the distance from the sun is the Earth. Venus has about 81% of the Earth's mass, and the planet surface is about 90% of the surface area. If you were to stand on Venus, you'd experience only 90% of the gravity that we have on Earth. The Earth has a relatively thick atmosphere containing some carbon dioxide, and Venus has a thick atmosphere containing carbon dioxide. The superficial similarities between the two planets, however, and there.

Starting point is 00:03:08 It's as if the Earth and Venus are like two children who were similar when they were younger, but when you see them decades later, one has become an investment banker, and the other one's become a bomb-throwing anarchist. For starters, Venus has a very peculiar rotation. The Earth rotates about its axis once every 24 hours. On the other hand, Venus is the only planet in the solar system where a day lasts longer than a year. Venus takes only 224 days to travel around the sun due to its proxswain. proximity to the sun and the shorter path it has to follow. Its period of rotation around its axis,

Starting point is 00:03:43 however, takes 243 days, and more on the reason for that in a bit. Moreover, Venus rotates the wrong way. If you were to observe the rotation of every planet in the solar system from the vantage point of looking down on the sun's north pole, every planet rotates counterclockwise. One of only two exceptions to this is Venus, which rotates clockwise, the other being Uranus. If you were standing on Venus, you would see the sun rise in the west and set in the east. This is known as retrograde motion. The history of observations of Venus date back to the earliest human observations of the sky. Because Venus is so bright, with only the sun and moon being brighter, every culture and

Starting point is 00:04:26 civilization knew about it and had a word for it. Most cultures didn't know that the bright star that sometimes appears in the morning was the same star that sometimes appeared in the evening, because there would often be several days between the observation of the two where the star didn't appear at all. Both ancient Chinese and Greek astronomers thought that they were two different stars. When Venus appeared in the morning, the Chinese called it the starter of brightness, and the Greeks called it phosphorus. The Chinese called Venus in the evening, the excellent West one, and the Greeks called it Hesperus. However, not everyone believed this. The Roman author,

Starting point is 00:05:02 Pliny the Elder acknowledged that the mathematician Pythagoras thought that they were the same object, as did several other Greeks. The name Venus comes from the Roman goddess of love. Other cultures such as the Babylonians and the Sumerians also used their goddess of love as the name for the planet. Real understanding of Venus didn't come until the invention of the telescope. When Galileo Galilei turned his telescope towards Venus, he found that it exhibited phases just like the moon did. The phases of Venus were an important mile. in proving the heliocentric model of the solar system, because Venus could only have phases if it orbited the Sun and not the Earth. As astronomers made more observations of Venus and they got a

Starting point is 00:05:44 better understanding of its orbit, they found that very infrequently it would pass directly in front of the Sun, an event which is known as the Transit of Venus. A transit of Venus is the same principle as a solar eclipse, except that Venus is much farther away than the moon and only appears as a dot across the sun. The English astronomers Jeremiah Horrocks and William Crabtree predicted the first transit of Venus in 1639. Transits of Venus tend to occur in pairs a few years apart from each other with gaps of over a century between the pairs. The transits of 1761 and 1769 were one of the first true global scientific projects, with astronomers all around the world taking part. The reason it was so important is because it allowed for a means of measuring the distance

Starting point is 00:06:31 from the Earth to the Sun via parallax from different observation points across the planet. There were transits in 1874 and 1882 and again in 2004 and 2012. There will not be another transit of Venus until 2117 and 2125. In 1761, the Russian astronomer Mikhail Lamanasov discovered something that proved to become of Venus's defining characteristic. It had an atmosphere. The atmosphere of Venus made it very difficult to learn much about it. The rotation of Venus was an open question for a long time because nobody could see the surface. Astronomers were able to eventually discern some of Venus's secrets in the 20th century by observing Venus in the ultraviolet spectrum and by measuring the oblateness of the planet.

Starting point is 00:07:17 Oblatanus is a measure of how flat or squished the planet is. You may have heard that the Earth is actually an oblate spheroid, which means that it's ever so slightly bigger around the equator than it is around the poles. The oblateness of the Earth is due to its rotation. Venus has almost no oblateness, which was a clue as to its slow rotation. As the space age began, Venus was the target of several early interplanetary probes. The Soviet Venera 1 was the first human object sent to another planet back in 1961. However, it lost contact en route and no data was sent back. The first successful mission to another planet was Mariner 2 in 1962, which managed to send back images and data. In 1970, the Soviet Venera 7 became the first probe to do a soft landing on another planet,

Starting point is 00:08:04 and in 1975, Venera 9 and 10 became the first and only probes to land on Venus and send back images of the surface. What was discovered from all these early probes was that Venus was perhaps the most inhospitable place in the solar system. Any thoughts about Venus potentially harboring life or quashed when it was discovered what conditions were like on the surface. If you were to stand on the surface of Venus, you'd die. It would only be a question of what of the many possible things on Venus would kill you first.

Starting point is 00:08:37 The first thing that would kill you is the composition of the atmosphere. The Venetian atmosphere is 96.5% carbon dioxide and 3.5% nitrogen, with the rest being other trace gases. So you'd suffocate because there was no oxygen. to breathe. The next thing that would kill you is the incredible pressure of the atmosphere. The surface pressure on Venus is 93 bar or 1,350 pounds per square inch. Or to put that in terms, it might be easier to understand. Standing on the surface of Venus is like being 900 meters or 3,000 feet below the surface of the ocean. So if you weren't being suffocated, you'd be crushed.

Starting point is 00:09:16 Oddly enough, despite nitrogen being only 3.5% of the atmosphere on Venus, there's actually four times as much gross nitrogen in Venus's atmosphere than in Earth, where it makes up almost 70% of the atmosphere. This incredibly dense atmosphere is the reason why the planet rotates so slowly. The drag from the planet's atmosphere has caused it to slow down. The final thing which could kill you on Venus is the heat. The super dense atmosphere of CO2 and its position close to the sun has led to a new. out-of-control greenhouse effect on the planet. The average surface temperature on Venus is

Starting point is 00:09:52 467 degrees Celsius or 872 degrees Fahrenheit. There are several reasons for the unique and deadly atmosphere on Venus. The first is that it's probably the most volcanically active planet in the solar system. In fact, some astronomers think that volcanoes on Venus are still active today. This massive outgassing poured so much gas into the atmosphere that it led to incredible pressures. The other big factor may have been the lack of any sort of natural magnetic field. The magnetic field on Earth protects the planet from the sun's solar wind. On Venus, there's no protection, and most lighter gases are stripped from the atmosphere, leaving only heavier gases. While the surface has a high pressure, Venus has a very complex atmosphere as you go up.

Starting point is 00:10:37 In fact, about 60 to 65 kilometers above the surface, the pressure and temperature is similar to that of Earth. In fact, it's led many people to think that floating outposts on Venus might be possible. Oxygen in Venus's atmosphere would serve as a lifting gas, similar to hydrogen or helium on Earth. The hellish conditions on the surface of Venus have resulted in more attention being paid to Mars as an object of exploration, as it's simply easier to explore. If life is to be found somewhere in the solar system, it probably isn't going to be found on the surface of Venus. As of the date of this recording, there have been 46 missions sent to Venus, the majority of which occurred in the 1960s and 1970s. There are only six future missions to Venus that are in the planning stages, with missions

Starting point is 00:11:24 by India, the United States, Russia, and the European Space Agency. There has even been a proposition that we send humans to Venus before we send them to Mars, not to land on the surface, but just to do a fly-by and test living in interplanetary space, something which no human being has done before. It would be easier, faster, and cheaper than doing a flyby of Mars. Despite being the morning and evening star, which captured the attention of early humans for thousands of years, Venus has actually become less alluring to researchers over time. The conditions on the planet make it so difficult to explore that it's simply easier to pick the low-hanging fruit on planets such as Mars. The executive producer of Everything Everywhere Daily is Charles Daniel. The associate

Starting point is 00:12:11 producers are Thor Thompson and Peter Bennett. I just want to thank everyone, including the show's producers, who support the show over on Patreon. If you'd like to support the show, just head over to patreon.com, which is currently the only place where you can get show merchandise. Also, if you want to talk to other listeners about the show, head over to our Facebook group or Discord server, both of which have links in the show notes.

Everything Everywhere Daily: History, Science, Geography & More - Venus

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