Earth in Space and Time (Part 2) Our Solar System

Name all the planets you can think of. What object is at the center of the solar system? What force keeps the planets from flying out of the solar system?

Some fun facts about Our Solar System: Our solar system is made up of the sun and everything that travels around it. This includes eight planets and their natural satellites such as Earth's moon; dwarf planets such as Pluto and Ceres; asteroids; comets and meteoroids. The sun is the center of our solar system. It contains almost all of the mass in our solar system and exerts a tremendous gravitational pull on planets and other bodies. Our solar system formed about 4.6 billion years ago. The four planets closest to the sun -- Mercury, Venus, Earth, and Mars -- are called the terrestrial planets because they have solid, rocky surfaces. Two of the outer planets beyond the orbit of Mars -- Jupiter and Saturn -- are known as gas giants; the more distant Uranus and Neptune are called ice giants.

Most of the known dwarf planets exist in an icy zone beyond Neptune called the Kuiper Belt, which is also the point of origin for many comets. Many objects in our solar system have atmospheres, including planets, some dwarf planets and even a couple moons. Our solar system is located in the Milky Way Galaxy. There are most likely billions of other solar systems in our galaxy. And there are billions of galaxies in the Universe. We measure distances in our solar system by Astronomical Units (AU). One AU is equal to the distance between the sun and the Earth, which is about 150 million km (93 million miles). NASA's twin Voyager 1 and Voyager 2 spacecraft are the first spacecraft to explore the outer reaches of our solar system.

What is a Solar System? A solar system refers to a star and all the objects that travel in orbit around it.

Our Solar System… Our solar system consists of the sun - our star - eight planets and their natural satellites (such as our moon); dwarf planets; asteroids and comets. Our solar system is located in an outward spiral of the Milky Way galaxy. Each planet’s orbit around the sun is a flattened circle called an ellipse.

Who is our neighbor? (Fun FactS) The closest spiral galaxy to the Milky Way is Andromeda, a galaxy much like our own Milky Way (but bigger). The Andromeda Galaxy (M31) is the closest large galaxy to the Milky Way and is one of a few galaxies that can be seen unaided from the Earth. In approximately 4.5 billion years the Andromeda Galaxy and the Milky Way are expected to collide and the result will be a giant elliptical galaxy Andromeda is approaching our galaxy at a rate of 670,000 miles per hour.

The basic components of a galaxy… (Fun Facts) Spiral galaxies have three main components: a bulge, disk, and halo. The bulge is a spherical structure found in the center of the galaxy. This feature mostly contains older stars. The disk is made up of dust, gas, and younger stars. The disk forms arm structures. Our Sun is located in an arm of our galaxy, the Milky Way. The halo of a galaxy is a loose, spherical structure located around the bulge and some of the disk. The halo contains old clusters of stars, known as globular clusters.

Solar System Let’s start with Earth’s closest star, the Sun. Click on the solar system link to learn about the Sun, and visit the planets and other small bodies in the Solar System. (Additional resource: Solar System gizmo from explorelearning.com) What do we know about the Sun? The Sun like all stars is a massive ball of exploding gas giving off light and heat that travels out in all directions. The Sun applies a huge pulling force called gravity to everything within 373 million miles. Planets, moons, and other objects travel around or orbit the Sun. Our Solar System has eight planets, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The web site link can be used to take a closer look at the planets and then use the Comparative Planet Table to compare their properties. Resource Link: http://www.windows.ucar.edu/tour/link=/our_solar_system/solar_system.html

Planet A planet is a large ball of rock or gas that follows a path round the sun. There are eight planets. Sun  Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune (My Very Educated Mother Just Showed Us Neptune!) (My very Excited Mom Just Served Us Nutella) Have students come up with a new sentence to remember the eight planets.

Planets in Our Solar System The inner planets of Mercury, Venus, Earth, and Mars are small and mostly solid. The outer planets of Jupiter, Saturn, Uranus, and Neptune are large and made mostly of gases. Between the inner and outer planets is a belt of rocks called asteroids that orbit the sun.

The solar system includes the sun and eight planets.

Mercury: 1st planet closest to the Sun. Surface: rocky with craters Atmosphere: Very thin Can be very hot during the day and very cold at night. Moon: none One day : 59 earth days

Venus: Second closest planet to the sun Surface: rocky, with large plains and tall mountains. Atmosphere: very thick Moon: none Only a bit smaller than Earth Has lots of lightning and hurricane-force winds Rotates in the opposite direction of Earth’s One Orbit: 243 earth days (about 7 months) The hottest planet in the Solar System The Sun rises in the west (unlike Earth)

Earth The 3rd planet from the sun. It is called a “Rocky Planet,” because it is made of rocks. Sometimes called the “Water Planet,” because it is the only planet with the water we need to live. Earth orbits, or circles, the sun in 365 ¼ days, or one year. While it is orbiting the sun, it also spins like a top! It spins 1 time in 24 hours, and that is why Earth’s day lasts for 24 hours. Earth is the only known planet where plants and animals live. Moon: one Moon 1 day: 24 hours

Mars: Fourth planet from the sun. Nicknamed: The red Planet Surface: rocky; craters, mountains, and canyons. Has a red sky and dust storms that sometimes covers the entire planet. No liquid water, but ice covers its North Pole area in the winter. Thin atmosphere 2 moons among the smallest in our solar system (Phobos and Deimos) 1 day: 24 hours

More Mars info: The first spacecraft to fly by Mars was in the early 1970’s. The twin Mars Exploration Rovers, known as Spirit (MER-A), and Opportunity (MER-B), were launched on separate rockets in 2003. Each rover successfully landed on the red planet in January of the following year. The rovers, designed to operate for three months on Mars, far exceeded their design life. Spirit operated for around six years. (March, 2010) Opportunity was functional until it stopped sending signals on June 10th, 2018

Asteroid Belt: The Asteroid Belt is a region between the inner planets and outer planets where thousands of asteroids (large and small) are found orbiting around the Sun.

Jupiter Fifth planet from the Sun. Largest planet in the solar system (1,321 Earth’s could fit inside it!) Atmosphere: very thick and made mostly of hydrogen gas Moons: 79 Seven missions have flown by Jupiter — and one actually orbited the planet. Another spacecraft, named Juno (launched in 2011), arrived in Jupiter on July 4, 2016. its primary goal is to reveal the story of Jupiter’s formation and evolution. Its end of mission is expected will be on July 2021. One day: 10 hours The Great Red Spot- a huge storm.

Saturn Sixth planet from the sun Second largest planet in the Solar System. Has largest set of rings of any of the planets Rings are made of chunks of ice and rock. Thick atmosphere Has 62 known moons. One day: 10.5 hours

Uranus: Seventh planet from the sun Has a poisonous atmosphere with strong winds and frigid temperatures. The planet’s axis points almost directly at the Sun, so you might think of Uranus as rotating on its side. Has 27 known moons One day: 17 hours

Neptune: Eighth planet from the sun The windiest of all the planets. Thick atmosphere Very cold planet (below -220 degrees C) Has 13 known moons Has smaller rings One day is 16 hours One year: 165 years

Planet Characteristics Size Length of Its Orbit Composition of Planet ( Use a reference to fill in this data) Mercury Small   Shortest or a measurement Rocky No moons Venus small Longer than Mercury but shorter than Earth’s or a measurement Earth Longer than Venus but shorter than Mar’s or a measurement 1 moon Mars Longer than Earth but shorter than Jupiter’s or a measurement 2 moons Jupiter Largest Planet Longer than Mars but shorter than Neptune’s or a measurement Gases and dust Many moons Saturn Large Longer than Jupiter but shorter than Uranus’s or a measurement Uranus Longer than Saturn but shorter than Neptune’s or a measurement Neptune Longer than Uranus but shorter than Pluto’s or a measurement

Comparing Planets in Our Solar System Length of Year in Earth Days Number of Moons Length of Year in Earth Days Mercury 88 Venus 224.7 Earth 1 365 Mars 2 687 Jupiter 63 4,329 Saturn 62 10,752 Uranus 27 30,660 Neptune 13 60,152

Planet Characteristics Inner Planets Outer Planets Size: Small Rocky and Solid Few or no moons Temperature: Hot to warm Mercury Venus Earth (one moon) Mars Size: Large Composed of gas and dust Many moons Temperature: Cool to cold Jupiter Saturn Uranus Neptune Review characteristics of the inner and outer planets. Click on links to view Study Jams slide show.

Why isn’t Pluto a planet? Pluto is a dwarf planet in the Kuiper belt, a ring of bodies beyond Neptune. In order to be a planet you need the following: It must orbit the Sun (*) It is nearly round (*) It must have a cleared path /orbit due to its gravitational pull (X)