Download
1 / 48
480 likes | 595 Views
Unit 6 – Jupiter. The outer planets are also known as the gas giants since they are made mostly of gas. We will talk later this year about why they are mostly gas while the inner planets are mostly rock. In order of distance from the Sun, the outer planets are:
E N D
Unit 6 – Jupiter The outer planets are also known as the gas giants since they are made mostly of gas. We will talk later this year about why they are mostly gas while the inner planets are mostly rock. In order of distance from the Sun, the outer planets are: In order of diameter, the outer planets are: In order of mass, the outer planets are: Jupiter is over _____________ times as far from the Sun as Mars. The outer planets are much more spread out than the inner planets. Remember the scale model on the football field.
Jupiter Jupiter is by far the largest most massive planet in the solar system. It is more than twice as massive as all the other planets combined. distance from Sun – ____ AU diameter – _________ miles Jupiter is _______________ in Roman mythology.
Jupiter Jupiter is over ______ times wider than Earth and has _____ times the mass. It would take over _______ Earths to fill it. It is the __________ brightest “star” in the sky and is much brighter than Mars even though Jupiter is over 8 times farther away from Earth than Mars.
Orbit and Rotation One Jovian day is about ____ hours long. One Jovian year is just under ____ Earth years. Jupiter has no solid surface so it experiences differential rotation – Jupiter is so big, rotates so fast, and is so fluid that it _______________________________.
Internal Structure Jupiter is about _______________ and ________________ by mass with traces of heavier elements. Why does Jupiter (and the other gas giants) have so much hydrogen and helium while the inner planets have very little?
Internal Structure Jupiter has a rocky core that is about _____ times the mass of the entire Earth. That seems like a lot but remember that Jupiter itself is over 300 times as massive as Earth. The core is the nucleus on which the rest of the planet formed. The pressure at the core is ten times as much as Earth’s core and the temperature is eight times as much as Earth’s core. But even though Jupiter is mostly hydrogen and helium just like a star, it is not nearly massive enough to __________________ as stars do.
Internal Structure Above the core is some weird stuff. There is so much pressure that even at the very high temperature, the hydrogen and helium are compressed to a liquid state. Not only is it liquid, the hydrogen is also in a liquid metallic form which is an excellent conductor of electricity. The outer layer of Jupiter is mostly molecular hydrogen and helium.
Magnetosphere The liquid metallic hydrogen is a strong ___________________ and since it also ____ _____, Jupiter has an enormous magnetic field. The magnetic field extends almost ___________ miles towards the Sun (Earth’s is about 40,000 miles towards the Sun). But on the far side of the Sun, Jupiter’s magnetic field extends over _______________ miles which is well beyond _______________. This is due to the __________ blowing it away from the Sun.
Magnetosphere The magnetic field is so strong that it captures any charged particles that come to it. Most dangerous to equipment and people are _______ ions because they are relatively large. Recall that _______________________ sent to Jupiter were almost fried by this radiation. Any craft sent to Jupiter (or near Jupiter if slingshotting past it) must have extra shielding from this radiation. An unprotected human exposed to this radiation would ____________.
Magnetosphere Just like Earth, Jupiter’s magnetic field funnels charged particles to the poles where they come into contact with the atmosphere. This forms ________ that are much larger than Earth itself. Intense lightning storms have been observed on Jupiter as well. There is no rain though.
Atmosphere The Jovian atmosphere is the most turbulent in the solar system. When viewed through a telescope, the atmosphere appears to be striped. These stripes are alternating high/low pressure bands. belts – ________ regions zones – ________regions
Storms The most famous feature on Jupiter is the _____ ______________. It is a huge hurricane about twice as big as Earth and has been around for at least 300 years. Many smaller storms form and dissipate every few years or decades. All of the storms, including the GRS, are located where the belts and zones meet.
Storms The weather on Earth is ultimately powered by _______________. This is not the main power source of Jupiter’s weather because ___________________. The reason behind the storms was not clear until it was discovered that Jupiter radiates twice as much energy into space as it receives from the Sun so Jupiter’s storms must be powered ___________________. Jupiter is slowly collapsing in on itself due to its own gravity in a process called _________________ _____________. As the material falls in, the pressure ____________and temperature _________. The heat works its way out and that combined with Jupiter’s very fast rotation powers the turbulent atmosphere.
More Belts and Zones Jupiter’s turbulent atmosphere constantly changes. What’s the big difference in these pictures?
More Belts and Zones The belts are ___________ material whereas the zones are ___________ material. So the belts are lower in the atmosphere than the zones. Occasionally, and nobody really knows why, a belt disappears fairly quickly. We know that the belt doesn’t completely dissipate because The most likely explanation is that the belt sinks even lower than it already is and the higher zones on either side of the belt push material on top of it.
More Belts and Zones The belt always comes back and this most recent appearance and disappearance is the first time that it has been studied closely enough to see signs of the belt reappearing.
Rings A totally unexpected discovery by Voyager 1 is that Jupiter has _______ very faint rings. They are made mostly of rock and are very thin, very narrow, and very dark. They were only discovered after a couple Voyager 1 scientists insisted that they might as well look for them after a trip of a few hundred million miles.
Jovian Moons Jupiter is sometimes called a mini-solar system due to it’s numerous moons. It has _____ large moons and around _____ small ones. The large moons are known as the _______________ moons since _______________ was the first to observe them.
Jovian Moons All four of the Galilean moons have nearly circular orbits above Jupiter’s equator and are ______________________ to Jupiter. Io, Europa, and Ganymede are in a 1:2:4 _________________________. This means that Europa’s oribtal period (time it takes to go around Jupiter) is twice as long as Io’s oribtal period. Ganymede’s is four times as long as Io’s (twice as long as Europa’s). Callisto is almost in this resonance also.
Io Io is the innermost large moon and is slightly _________ than our Moon. It has a fairly large solid iron core relative to its size and a rocky mantle.
Io Io has very few craters so its surface is very _________. Erosion does not occur because ______________. Instead, Io is the most ______________________body in the solar system. Its surface is almost completely regenerated every few years. It even has lakes of molten ______.
Io Io is about the size of our Moon so it should be solid all the way through like our Moon. Its mantle is kept liquid by _____________________________ between Jupiter and the other Galilean moons which result in a tide of over _________ ft on Io (imagine a tide that big on Earth’s oceans!). This tide wobbles back and forth within Io which creates a lot of _____________ which is enough to melt Io’s mantle. In addition, Io’s orbit cuts across Jupiter’s magnetic field lines which generates an electric current. This also heats Io but not nearly as much as the tidal forces.
Io Jupiter’s magnetic field is deadly as it is but Io is what makes it really deadly. Since Io orbits within the magnetic field, any charged particles erupting from Io’s volcanoes get carried away and accelerated by the magnetic field.
Europa Smaller than our Moon, Europa is the smallest of the Galilean moons. Like Io, it has a solid iron core and rocky mantle. Unlike Io, however, Europa is covered in a layer of water ice. Why?
Europa There are very few craters on Europa so its surface is __________ also but there is no appreciable atmosphere nor volcanoes. There are many streaks stretching across the icy surface which indicate the surface is slowly moving and liquid water is coming up from underneath and filling the cracks.
Europa Europa also has a magnetic field that is generated by it cutting across Jupiter’s magnetic field. This is only possible if a liquid conducting material is below the surface. All of this leads to the most important aspect of Europa: beneath the icy surface lies a ___________________. It is underneath several miles of ice but it may be ____ miles deep containing more water than all of Earth’s oceans combined. Europa’s ocean should be frozen solid but it is heated and kept liquid by the same tidal interactions that make Io volcanic. The tides are much weaker on Europa since it is __________________________.
Ganymede Ganymede is the largest moon in the solar system. It is larger than Mercury and would easily be a planet if it were not _________________. Its internal structure is similar to Europa with an iron core, rocky mantle, and icy crust. Ganymede does not have a liquid ocean but it probably has a slushy water/ice layer beneath the surface.
Ganymede The surface relatively young but much older than Io and Europa. The ancient craters have been smoothed out over time by the _____________________________. These “ghost craters” are called _________________.
Callisto Unlike the other Galilean moons, Callisto has a more or less uniform composition throughout – in other words, it has no distinct core or mantle. Scientists are not sure how Callisto and Ganymede could be right next to each other yet be so different.
Callisto The surface of Callisto is completely saturated with craters so it is very ______. Scientists use Callisto as a reference to which to compare other bodies. The only big mystery with Callisto is why it is so different from Ganymede in terms of internal structure. Speculation includes the idea that Callisto used to be closer to Jupiter and tidal forces allowed its interior to partially melt but not melt enough for heavier elements to sink to the core. Callisto most likely has a thin slushy ice layer similar to Ganymede.
Callisto The largest feature on Callisto’s surface is ____________________. It is a monstrous multi-ring impact basin. How were the rings formed?
Small Moons Jupiter has over 60 known small moons and many more that have not been discovered. Why is it difficult to see small moons around Jupiter? The small moons are usually divided into two groups: inside the orbit of Io and outside the orbit of Callisto.
Inner Moons Only four very small moons are known to orbit closer than Io. Metis and Adrastea orbit within Jupiter’s main ring and are possibly where the ring material comes from. Tidal forces are very strong close to Jupiter so the moons were broken up and formed the ring. Amalthea is redder than Mars but its color is due to sulfur compounds coming from _____.
Outer Moons The vast majority of Jupiter’s moons orbit beyond Callisto. And a good many (but not all) of those have highly inclined retrograde orbits. “highly inclined” means “retrograde” means Because of this, astronomers believe that these moons were once one single body that Jupiter’s tidal forces broke up. Their compositions match that of asteroids so they probably originated _______________________________________.
Jupiter’s Effect on Us We will discuss this in much more detail later on but some believe that Jupiter is a cosmic vacuum cleaner that sucks up comets and asteroids protecting Earth from impacts. Others think that Jupiter actually grabs comets and asteroids and slingshots them towards us. Not much research has been done on this but it is definitely true that Jupiter has a major effect on the orbits of comets and asteroids.
Roche Limit We will talk in detail later about comets and asteroids but Jupiter is a great place to introduce the Roche Limit – the closest a body (usually a satellite) held together only by gravity can pass to a larger body (primary) without _______________________. Within the Roche limit, tidal forces of the primary will ___________________________.
Roche Limit This is better explained in a drawing.
Roche Limit The formula for the Roche Limit is the following: where d is the Roche limit R is the primary’s radius rM is the primary’s density rm is the satellites density You will be given this formula so don’t bother memorizing it.
Roche Limit Earth’s density is 5.52 g/cm3 and the Moon’s density is 3.35 g/cm3. Earth’s radius is 3959 miles. How close to Earth’s center would the Moon have to get for the Moon to break apart?
Roche Limit A small body has a density of 0.5 g/cm3 while Jupiter’s density is 1.33 g/cm3. Jupiter’s radius is 44,000 miles. What is this body’s Roche limit?
Shoemaker-Levy 9 The small body on the previous page was a comet discovered in 1993. It was quickly determined that it had recently passed less than 149,000 miles from Jupiter (the Roche limit). Because of this, SL9 ______________ and it was calculated that in 1994, the comet fragments would pass within 28,000 miles of Jupiter’s center. Jupiter’s radius is _______ miles which means that the fragments _________.
Shoemaker-Levy 9 Again, if a body passes within the Roche limit, it will break up if it is not held together by strong intermolecular forces (chemical bonds, etc.). Since comets are essentially dirty snowballs, they break apart easily. The tidal forces that break up the comet are the same tidal forces that make Earth’s tides. These forces stretch Earth along a line and they stretch the comet as well. If the comet breaks up, its fragments are stretched along the same line which is why the fragments don’t stay bunched up.
Shoemaker-Levy 9 Over nine days in July 1994, every large telescope, thousands of small amateur telescopes, the Hubble Space Telescope, the spacecraft Galileo (which was still on its way to Jupiter), and even _________ observed SL9 impacting Jupiter. The video you are about to see is in _________________ because it is easier to distinguish the impact fireball from the cloud tops. The impacts occurred on the opposite side of Jupiter so only _____________ and ________________ got to see the impacts actually occur. The pictures taken from Earth are a couple hours after impact.
Shoemaker-Levy 9 Overall, about 20 large fragments hit Jupiter. Each impact was as powerful or more powerful than the impact that killed the dinosaurs. The scars from the impacts remained on Jupiter for more than a year afterward which is amazing considering
Jupiter’s Effect on Us So does Jupiter help or hurt us when it comes to comets and asteroids? It is large enough to capture comets and asteroids fairly regularly (good for us) and affect the orbits of many more (good or bad for us). Spectacular events like SL9 are rare but smaller impacts happen often. And unfortunately for Jupiter’s moons, they sometimes pay the price for Jupiter’s strong gravity. This _____________________ is on Ganymede.
Galileo Spacecraft Since Jupiter is ___________________ and ____________________, it is ideal to be used to slingshot craft to the outer solar system. Many craft have been sent to orbit Jupiter the most significant being Galileo. It elliptically orbited Jupiter for 8 years collecting data on the moons, magnetosphere, and Jupiter itself. It also sent a probe into Jupiter’s atmosphere which survived to a depth of about 87 miles and a pressure of about 24 atmospheres. Prior to its rendezvous with Jupiter, Galileo made close flybys of two asteroids in the asteroid belt.
Galileo Spacecraft Galileo’s initial mission was to orbit for two years around Jupiter. The mission was extended to eight years even though its main antenna did not fully open and was therefore useless. Galileo made several close flybys of ________ which very nearly fried it even with its heavy shielding. In fact its cameras were all eventually ruined. With its fuel running out and most of its instruments inoperable, Galileo was _____________________ to prevent any possible bacterial contamination of Jupiter’s moons especially _________________.
