Everything Everywhere Daily: History, Science, Geography & More - Jupiter: The Biggest Planet in the Solar System

Starting point is 00:00:00 Ever since humans looked up at the night sky and noticed that some of the points of light moved, they have been aware of the planet Jupiter. However, it was the invention of the telescope that let us know just how amazing Jupiter was. And since then, we've sent eight probes to the planet to help us unlock its secrets. Learn more about Jupiter, the largest planet in the solar system, on this episode of Everything Everywhere Daily. What if your perceptions about the past were wrong? ThruLine is a podcast that takes you back in time to uncover the parts of the parts of of the story that may have gone unnoticed.

Starting point is 00:00:45 It effectively turned day into night. And how it shaped the world now. Time travel with us every week on the Thulein podcast from NPR. The planet Jupiter is the fifth planet from the sun. It's located in an average of 5.2 astronomical units away from the sun, with an astronomical unit being the average distance from the Earth to the sun. It orbits the sun once every 11.8 years, and a day on Jupiter is only, about 11 hours. The planet gets its name from the Roman god of the same name, who is the chief

Starting point is 00:01:21 Roman deity. It's the fourth brightest thing in the sky as seen from Earth, after the sun, the moon, and Venus. These fun facts, however, about Jupiter are really not what make this planet special. Probably the single most important fact about Jupiter is the fact that it is two and a half times the mass of all other planets in the solar system combined. Jupiter is huge. Some have called it a failed star, even though, to be honest, it's actually 75 times too small to start nuclear fusion. It would be more accurate to call it a failed brown dwarf, which is a star that fails to ignite. However, the cutoff for a brown dwarf is still about 13 times the mass of Jupiter. Because of its mass, Jupiter was probably the first planet in the solar system to form.

Starting point is 00:02:06 It is believed to have started with a large rocky core, and then via gravitational attraction gathered up much of the gases in its orbital zone. One theory of Jupiter's creation is known as the Grand TAC hypothesis, which suggests that Jupiter may have formed about 3.5 astronomical units away from the sun, and then migrated inward to about 1.5 astronomical units, and then finally moving to its current location at 5.2 astronomical units. Along the way, it may have been responsible for the destruction, collision, and creation of smaller rocky planets closer to the sun, including Earth. This migration of Jupiter might explain where it picked up so much of its mass. In a roundabout way, some astrophysicists think that Jupiter might have helped in the rise of life on Earth. And if you're wondering how a planet so far away might have influenced life on Earth, it's actually pretty simple. Asteroids.

Starting point is 00:02:57 Jupiter's huge gravity well probably meant that it sucked up an enormous amount of debris that was floating around the early solar system. Debris that could have hit Earth at some point. and this was illustrated by the 1994 impact of the Shoemaker Levy comet into Jupiter. The impact of the comet was actually able to be observed from terrestrial telescopes on Earth, as well as from the Hubble Space Telescope. However, this has been hotly contested, as other astrophysicists think that Jupiter is just as likely to gravitationally fling a comet in the direction of Earth. These two theories aren't necessarily contradictory.

Starting point is 00:03:30 While Jupiter might occasionally toss something in her direction, most of the objects that influences probably wouldn't go in the direction of Earth. Jupiter is what's known as a gas giant, which means that there is no solid surface to the planet. The composition of the planet is about 89% hydrogen, 10% helium, with the remaining 1% consisting of ammonia, methane, water, and other trace gases. The composition of the core of Jupiter is unknown, but there are many theories as to what it might be, and these include an exotic form of metallic hydrogen, as well as a possible supercritical fluid, which is a state where hydrogen is neither a gas nor a liquid. The pressures inside Jupiter are so great due to its gravity that some people have hypothesized that it could actually

Starting point is 00:04:13 rain diamonds deep inside of Jupiter. If you look at an image of Jupiter, one of the first things you'll notice are the bands of clouds that surround the planet. These clouds are the very top layer of the atmosphere, and they are mostly made up of ammonia crystals, as well as some sulfur, phosphorus, and carbon. Jupiter actually has an active weather system. The light-colored bands are known as zones, and the darker regions are called belts. By far, the most prominent feature on the surface of Jupiter has to be the Great Red Spot. The Great Red Spot is really just a massive persistent storm. The spot rotates counterclockwise about once every six days. We aren't exactly sure how old it is, but it at least dates back to

Starting point is 00:04:54 1813 when it was first definitively observed. However, there were older, cruder observations made in 1665, which also show some sort of spot which might have been the Great Red Spot. The Great Red Spot is believed to be a temporary feature on the planet. In just the last few years, its shrunken size, and it's entirely possible that at some point in the future, it could disappear entirely. At its maximum extent, the Great Red Spot was larger than the planet Earth. One of the things that no one knew about Jupiter until we sent probes to the planet was the presence of six cyclones, evenly spaced, which were located at Jupiter's south pole. Jupiter also has the strongest magnetosphere of any planet in the solar system,

Starting point is 00:05:35 which is 2,000 times more powerful than Earth's magnetic field. This results in some very powerful auroras in the North Pole and some weaker auroras in the South Pole. Jupiter doesn't get a lot of attention just because of the planet itself. As a gas giant, we can never really land on it. However, Jupiter is also home to its own mini solar system of bodies that orbit it. As of right now, Jupiter has a total of 79 moons, the most of any planet by a wide margin. Most of these are pretty small rocks. However, Jupiter is also home to four of the largest moons in the solar system, known as the Galilean moons. The Galilean moons were literally discovered by Galileo, and one of the first things that he discovered when he turned his telescope to the planet. He managed to track the movement

Starting point is 00:06:22 of the moons around the planet, and you can see the Galilean moons yourself with any halfway decent telescope or even a very good pair of binoculars. The largest moon is Ganymede. It's not only the largest moon of Jupiter, it's the largest moon in the solar system, and it's actually bigger than the planet Mercury. It has a solid core, probably made of iron, and its surface is of water ice. It's the only moon in the solar system that has its own magnetic field. There might actually be a liquid ocean under the ice with more liquid water than can be found on the planet Earth.

Starting point is 00:06:53 The second largest moon is Callisto. It is 99% the diameter of Mercury, but only one-third its mass. It's a mixture of rock and ice, and it also might have a liquid ocean over 100 kilometers beneath the surface. The third largest moon, and the one that's closest to Jupiter, is Io. Io just might be the oddest body in the solar system. It has the least amount of water of any body that we know of, and it is also the most geologically active body in the solar system as well. There are over 400 active volcanoes on Io,

Starting point is 00:07:24 and there have even been images captured by probes of eruptions being caught in the act. The surface of Iowa is mostly sulfur, which is responsible for its yellowish color, and the eruptions are caused by the extreme tidal forces of Jupiter and the other moons. And the smallest of the Galilean moons is Europa. It is slightly smaller than the Earth's moon, and it too has a rocky core with a water-iced crust. It is the smoothest object in the solar system, which might be caused by plumes of water vapor that have been observed erupting onto the surface. It too may harbor a liquid ocean under the surface, and many planetary scientists,

Starting point is 00:07:59 that it might be the best place in the solar system outside of Earth to look for evidence of life. While not easily visible, Jupiter also does have a very faint ring system around the planet. As soon as we had the capability to send interplanetary probes, Jupiter became one of the highest priority destinations to visit. The very first probes to send back images were Pioneer 10 in 1973 and Pioneer 11 in 1974. Voyagers 1 and 2 flew by in 1979 on their grand tour of the gas giants. Jupiter has also been used for gravitational assists on other probes which are going elsewhere, including the Ulysses mission to the Sun, the Cassini mission to Saturn, and the New Horizons mission to Pluto. There have been two missions that were sent purposely to Jupiter and then

Starting point is 00:08:44 were put into a Jovian orbit, the Galileo mission which arrived in 1995, and the Juno mission which arrived in 2016. The Galileo mission actually had a probe that was dropped into the Jovian atmosphere and returned data for almost an hour. The Juno mission is still active, and it's been extended until 2025. Future missions to Jupiter are all centered on its moons. The European Space Agency will be launching the Jupiter-Ice Moon Explorer, or Juice, in 2023, which will study Ganymede, Callisto, and Europa. NASA plans to launch the Europa Clipper mission in 2024, and its goal will be to do close flybys of Europa while in orbit around Jupiter.

Starting point is 00:09:25 Depending on what data these missions return, the next step might be a lander on the surface of one of the Galilean moons. Next to Mars, Jupiter, or to be more precise, Jupiter's moons, are the largest areas of interest in the solar system. The presence of ice and the high probability of liquid water beneath the surface of the moons makes it the most likely place in the solar system where some basic form of life may have arisen. This fact alone will make Jupiter an object of study and inquiry for centuries to come. Everything Everywhere Daily is an airwave media podcast.

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Everything Everywhere Daily: History, Science, Geography & More - Jupiter: The Biggest Planet in the Solar System

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