Chapter 14 Science cornell notes- The outer planets

Is pluto really a planet?

Astronomers don't believe that the size of pluto is worthy of being called a planet. If they had found other objects first, they wouldn't have called pluto a planet. There could also possibly be a tenth planet outside of pluto.

Neptune's Moons

Astronomers have discovered at least 13 moons orbiting neptune. The largest moon is Triton, which is a thin atmosphere. The South pole is covered by nitrogen ice.

Discovery of Uranus

Beyond saturn, they thought there was nothing until William Herschel saw a fuzzy image that was not a star. In fact, it was another planet called uranus. This discovery made him famous and it started an era of active solar system study.

Chapter 14 Section 4 Gas giants and Pluto

GAS GIANTS- are the names of the outer planets, because of their massive size. The first four outer planets are Jupiter, Saturn, Uranus, and Neptune, and are much larger and more massive than earth, and they do not have solid surfaces. The fifth outer planet is pluto, which is more like an inner planet. They have a bigger gravitational pull because of their size and they have atmospheres like the sun, that are made up of mostly hydrogen and helium. They have thick atmosphere, so that the gases of the planet do not escape. Much of the hydrogen and helium of the atmosphere is liquid however. The outer planets are very cold because of their great distance from the sun. All of these gas giants have moons, and are surrounded by rings. A RING- is a thin disk of small particles of ice and rock.

Jupiter's atmosphere

It is thick, and made up of hydrogen and helium. There is a great red spot feature of its atmosphere. It is a storm that is larger than Earth. The winds blow hundreds of km per hour. It shows no sign of going away, because it has no land to slow it down enough to stop it.

Jupiter's structure

It may have a dense core of rock and iron at its center, with a thick mantle of liquid hydrogen and helium that surrounds it. Its pressure is about 30 million times greater than Earth's surface pressure.

Jupiter's moons

Jupiter has four large moons that were discovered by Galileo. They are named, Lo, Europa, Ganymede, and Callisto. All four are larger than Earth's moon. However, there are dozens more moons to have been found orbiting around Jupiter.

Jupiter

Jupiter is the largest and most massive planet. Its size dwarfs other planets. Its mass is about 2 1/2 times of all the other planets combined.

Exploring Uranus

Only a few clouds were found on Uranus's surface, but it still allowed astronomers to discover that Uranus rotated in about 17 hours. Uranus's axis of rotation is tilted at an angle of about 90 degrees from the vertical. Uranus rotates from top to bottom, with its rings and moons rotating around the tilted axis.

Pluto's Orbit

Pluto is so far from the Earth that it revolves around the sun only once every 248 Earth years. It is very elliptical, in a way where at a certain point of its orbit, it is closer to the sun than Neptune!

Pluto

Pluto is very different from the gas giants. Pluto has a solid surface and is much smaller and denser than other outer planets. Pluto is smaller than Earth's moon. Pluto is a mixture of rock and ice. It has a single moon of its own, Charon. They are considered like a double planet since the moon of pluto seems to be almost as big as pluto.

Saturn's Moons

Saturn's largest moon, Titan, is larger than the planet Mercury, and was known as a point of light. Only little light can pass through the atmosphere because it is so thick. Four other moons of Saturn are each over 1,000 km in diameter.

Saturn's Rings

These rings are the most spectacular rings of all the planets. These rings are not solid, but instead are made of ice and rock, each traveling in its own orbit around Saturn. Each of the rings are divided into thinner rings, and are broad and thin, like a compact disc.

Uranus

This gas giant is much smaller than Jupiter and Saturn, it is twice as far from the sun as Saturn, so it is much colder. Because of the traces of methane in the atmosphere, uranus appears to be a blue-green. Uranus has thin rings around it that are flat, but they are much darker than saturn's rings.

Neptune

This is even farther from the sun than uranus, but in some ways, they look like twins. They are similar in size and color. Neptune is a cold blue planet, and has an atmosphere with visible clouds. Scientists think that neptune is shrinking and heating up, which crawls up to the surface which creates storms and clouds.

Saturn

This planet is the second largest planet in all of the solar system. It has a thick atmosphere composed of mostly hydrogen and helium. It also contains clouds and storms, but are less dramatic than those on jupiter. Saturn is also the only planet whose average density is less than that of water.

Summary:

This section talks about the outer planets, which are called gas giants. They are not solids, and one of the five isn't necessarily considered a planet. Jupiter, Saturn, Uranus, and Neptune are the gas giants. They all have moons and all have rings. They do not have solid surfaces, and are very far away from sun, so they are very cold.

Discovery of Neptune

This was discovered on accident by a mathematical prediction, in which they were questioning why Uranus was not following its predicted orbit. They came to conclusions that another planet was affecting its orbit, and when calculating where it to be, sure enough, it was there in the predicted place, and soon named Neptune.

Uranus's Moons

Uranus's 5 largest moons have icy and cratered surfaces. This shows of the meteors that hit these moons. Uranus's moons have lava flow on their surfaces, suggesting that material has erupted from inside each moon. There is so far a total of 27 moons found.

Exploring Neptune

When looking at Neptune, there was a great dark spot about the size of Earth. It was probably a giant storm. However, eventually, it went away, as did other spots on Neptune.

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outer planets