Our solar system Chapter 2 By Mrs. Shaw

What is our Solar System made of? Lesson 1: The Solar System What is our Solar System made of? Our solar system is made of planets, moons, comets, asteoroids, man-made satellites, and our sun.

Geocentric vs. heliocentric models of our Solar System Geocentric = Earth at center Scientists used to think that the earth was the center of our solar system. (Geocentric model) As technology advanced and we were able to see and explore our solar system we discovered that the sun is actually the center of our solar system. (Heliocentric model) Heliocentric = Sun at center

Review of planetary motion terms Period of rotation: the time it takes for an object to complete one full spin or rotation. Period of revolution: the time it takes for an object to travel once around the sun. Planets also move in an elliptical orbit around the sun.

What keeps the planets orbiting the sun? Universal law of gravitation: every object with mass has a gravitational attractive force to every other object with mass. Gravity depends on ; distance and mass. Therefore, the gravitational attraction of the sun with each of the planets is what keeps them orbiting the sun.

How do we measure distances in space? 1 AU = 149,598,000 km Distances in space are so large that we have a special unit of measurement for them called an astronomical unit. One astronomical unit (au) is equal to the distance from the earth to the sun. Notice on the chart how that distance relates to other distances in space.

Why are the four inner planets called the terrestrial planets? Lesson 2: The Inner Planets Why are the four inner planets called the terrestrial planets? The four inner planets in our solar system, Mercury, Venus, Earth, and Mars, are made of rocks and metals, and they all have a solid inner core.

Facts about mercury gravitational force: 37% of Earth’s gravity distance from the Sun: 0.39 AU or 57,910,000 km Mass / diameter: 5.5% of Earth’s mass and 38.3% of earth’s diameter Movement: rotation 59 days and 88 revolution days Temperature: Extremes from 450 degrees celsius on side facing sun To -170 degrees celsius on side not facing sun. atmospheric conditions: no atmosphere, rocky cratered surface with no moons.

Facts about venus gravitational force: 88% of earth’s gravity distance from the Sun: 0.72 AU or 108,210,000 km Mass / diameter: 81.5% of Earth’s mass and 95% of earth’s diameter Movement: rotation 244 days and revolution 225 days Temperature: Average temp 460 degrees celsius (hottest planet in solar system due to greenhouse effect ) atmospheric conditions: very thick atmosphere that is about 90 times greater than earth’s. Surface is 80% solid lava. No moons.

Facts about earth gravitational force: 100% = 9.80665 m/s2 distance from the Sun: 1 au or 149,600,000 km Mass / diameter: 100% Mass = 5.9736 x 1024 kg and 12,742 km diameter Movement: rotation 24 hours and revolution 365 days Temperature: perfect temp for liquid water to exist. Highest temp 57.8 degrees celsius and lowest is -89.2 degrees celsius atmospheric conditions: mixture of gases and water vapor make up atmosphere.

Facts about mars gravitational force: 38% of Earth’s Gravity distance from the Sun: 1.52 au or 227,920,000 km Mass / diameter: 10.7% earth’s mass and 53.2% earth’s diameter Movement: rotation 24.6 hours and revolution 1.88 years Temperature: range from -125 degrees celsius at poles and 20 degrees celsius at equator. atmospheric conditions: 95% Carbon Dioxide, thin and less dense than earth. Surface is mostly iron oxide which gives it the reddish color.

Why are the four outer planets known as the gas giants? Lesson 3: The Outer Planets Why are the four outer planets known as the gas giants? They are primarily made of hydrogen and helium gases. They also have strong gravitational forces due to their huge sizes. These forces apply tremendous pressure and cause the gases to change to liquids. Most have a thick gas and liquid covering a small solid core.

Facts about jupiter Jupiter has at least 63 moons! gravitational force: 264% of earth’s gravity distance from the Sun: 5.20 au or 778,570,000 km Mass / diameter: 318 times earth’s mass and 11.2 times earth’s diameter Movement: rotation 9.9 hours and revolution 11.9 years Temperature: ??? thought to be from 20 degrees celsius at coolest and about 35,500 degrees celsius at the core. atmospheric conditions: 90% hydrogen and 10 % helium and about 1,000km deep Close up picture of Great Red Spot – large storm of swirling gases

Facts about saturn Saturn has at least 60 moons! gravitational force: 115% of earth’s gravity distance from the Sun: 9.58 au or 1,433,530,000 km Mass / diameter: 95 times earth’s mass and 9.4 times earth’s diameter Movement: rotation 10.6 hours and revolution 29.7 years Temperature: ??? thought to be from -175 degrees celsius at coolest and about 11,700 degrees celsius at the core. atmospheric conditions: 90% hydrogen and 10 % helium and about 1,000km deep but it is also the least dense planet. 7 rings made of ice surround Saturn. Also has massive wind storms!

Facts about uranus Uranus has moons. Movement gravitational force: 93% of earth’s gravity distance from the Sun: 19.20 au or 2,872,460,000 km Mass / diameter: 14.5 times earth’s mass and . 4.0 times earth’s diameter Movement: rotation 17.4 hours and revolution 84.3 years Temperature: coldest planet in solar system reaching -225 degrees celsius and a core of 4,737 degrees celsius. atmospheric conditions: deep atmosphere made of hydrogen, helium, and methane.

Facts about neptune Neptune has 13 moons and a faint, dark ring system. gravitational force: 122% of earth’s gravity distance from the Sun: 30.05 au or 4,495,060,000 km Mass / diameter: 17.1 times earth’s mass and .3.9 times earth’s diameter Movement: rotation 16.1 hours and revolution 165.2 years Temperature: upper atmosphere is -218 degrees celsius but it’s core is around 7,000 degrees celsius. atmospheric conditions: like uranus it has a deep atmosphere made of hydrogen, helium, and methane. Close up picture of dark spot viewed by Voyager in 1989 but gone 5 years later.

What is the difference between a planet and a dwarf planet? Lesson 4: Other objects in the Solar System What is the difference between a planet and a dwarf planet? The definition of planet set in 2006 by the International Astronomical Union (IAU) states that, in the Solar System, a planet is a celestial body which: Is in orbit around the Sun, Has sufficient mass to assume hydrostatic equilibrium (a nearly round shape), and Has "cleared the neighborhood" around its orbit. A non-satellite body fulfilling only the first two of these criteria is classified as a "dwarf planet". The reason that Pluto fails as a major planet is because it has not "cleared its neighborhood." Pluto's orbit crosses that of Neptune, a vastly larger body. Pluto also shares its orbit with the Kuiper belt, a swath of small icy bodies beyond Neptune.

What is the difference between a comet, asteroid, and meteor? Asteroid: A small, inactive body, composed of rock, carbon or metal, which is orbiting the sun. Comet: a small, sometimes active object, which is composed of dirt and ices. Comets are characterized by dust and gas tails when in proximity to the sun. Meteoroid: a small particle from an asteroid or comet orbiting the sun. Meteor: a meteoroid that is observed as it burns up in the earth's atmosphere – (a shooting star). Meteorite: a meteoroid that survives its passage through the earth's atmosphere and impacts the earth's surface.   Asteroid Comet