Solar System Solar system- the sun and all objects that orbit the sun due to its gravity
Solar System Formation The Nebula Hypothesis
Parts of the Solar System Planet- a celestial body that is in orbit around the Sun, has sufficient mass so that it assumes a hydrostatic equilibrium (nearly round) shape, and has "cleared the neighborhood" around its orbit
Parts of the Solar System Planets There are 8 planets in our solar system. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune Distance from the sun determines characteristics density of material decreases with distance from the sun
Parts of the Solar System Dwarf planet- a celestial body that is in orbit around the Sun, has sufficient mass so that it assumes a hydrostatic equilibrium (nearly round) shape, but has NOT "cleared the neighborhood" around its orbit (i.e. Pluto, Ceres, Eris, Makemake & Haumea)
Parts of the Solar System Moon- body that orbits a planet or an asteroid as those objects orbit the sun
Parts of the Solar System Asteroids- solid rocky or metallic bodies that orbit the sun Most are in a belt between Mars and Jupiter
Parts of the Solar System Comets- balls of ice and rock or metal that turn to gas when they are heated by the sun Heating by the sun forms a tail, which is blown away from the sun by the solar wind Take weeks to leave our sky.
Comets
Parts of the Solar System Meteoroid- very small solid fragment that orbits the sun Most are the size of a dime or grain of sand. Meteor- meteoroid that makes a streak when it burns up in Earth s atmosphere Also called shooting stars. Meteor shower: when Earth passes through the orbit of a comet where there is a lot of debris, so we get lots of streaks of light as they hit our atmosphere Meteorite- meteoroid that hits Earth Impact crater- depression formed when meteorites hit Earth.
Impact Craters Meteor Crater, AZ 180 meters deep and 1.2 km in diameter with an eroded rim standing 30-60 m high Lunar Impact Crater
Planet Characteristics Terrestrial Planet Properties close to the sun and mostly solid Mercury, Venus, Earth, Mars Small diameters, high densities, few or no moons, no rings, have impact craters
Mercury Ball of rock with iron core, temperatures of -279 F to 800 F, many impact craters, no atmosphere or water Caloris Basin
Venus Runaway Greenhouse Thick clouds, acidic rain, poisonous atmosphere, temperatures of 890 F, many volcanoes
Earth, The Water Planet
Valles Marineras - 4000 km (2490 mi) long, 7km (4mi) deep, 200km (125mi) wide Mars
Planet Characteristics Jovian Planet Properties far from the sun and are largely gaseous Jupiter, Saturn, Uranus, Neptune Large diameters, low densities, many moons, rings, they may have a small solid core, no impact craters
Jupiter the Largest Planet The Great Red Spot a hurricane that has lasted at least 300 years so far, and is large enough to fit Earth inside!
Uranus Uranus is tilted almost completely on its side, during summer the sun never sets, during winter the sun never rises!
Motions of the Planets-Rotation and Revolution Rotation- spinning of an object on an imaginary axis Determines the length of day. Revolution- a planet s movement around the sun in a path called an orbit. Determines the length of the year. Ellipse- the oval shape of a planet s orbit. Foci- two fixed points within an ellipse.
Eccentricity of Planet Orbits Eccentricity- the degree of oval-ness of an ellipse, or how far an ellipse is from being a circle Eccentricity of an ellipse = distance between foci = d length of major axis = L As the foci become farther apart, the ellipse becomes more oval and the eccentricity approaches 1 As the foci are brought closer together, the ellipse becomes more circular and the eccentricity approaches zero.
Eccentricity
Varying Distance of Planets From the Sun The elliptical shape of a planet s orbit causes it to vary in distance from the sun during revolution. Ex. Earth is 147, 000, 000 km from the sun in January (perihelion=closest point in its orbit) and it is 152, 000, 000 km from the sun in July (aphelion=farthest point in its orbit)
Inertia, Gravitation, Orbital Velocity/Speed and Planet Orbits Inertia- an object at rest stays at rest and an object in motion stays in motion (with the same direction and speed) unless an opposing force acts on it. Gravitation- the attractive force that exists between any two objects in the universe Greater mass = greater attraction The closer the objects are = greater attraction When a planet is close to the sun its orbital speed is greater than when it is farther from the sun. Orbit is a dynamic equilibrium between inertia & gravity
Planetary Orbit Perihelion Moves fastest January Aphelion Moves slowest July
Planetary Orbit Body moves faster nearer the sun Body moves slower away from the sun Movie explaining Keplerian motion Kepler's first two laws : 1) The orbit of a planet about the Sun is an ellipse with the Sun at one focus. 2) A line joining a planet and the Sun sweeps out equal areas in equal intervals of time.
Gravity F = G mass of A mass of B F= force of attraction between two objects d 2 G= universal gravitational constant (6.67 x 10-11 N m 2 /kg 2 ) d= distance between the centers of gravity of the two objects
Gravity Let s look at attraction between a human (150lbs, 68kg) & Earth at Earth s surface. F= G (6x10 24 kg) (68kg) (7,000,000 m) 2 F= 555 N What about attraction between two humans. F= G (68kg) (68kg) (1m) 2 F= 3.08x10-7 N = 0.000000308 N Which one would have more of an effect? EARTH, of course!
Scale drawing of the relative sizes of planets and moons in the solar system Which celestial body has the greatest gravitational attraction? Which planet?