PhysicsI. Vocabulary 1. Planet- a celestial body that orbits the sun, is round because of it’s own gravity, and has cleared the neighborhood around it’s orbital path 2. Solar system- the sun and all of the planets and other bodies that travel around it 3. Satellite- a natural or artificial body that revolves around a celestial body that is greater in mass 4. Phase- the change in the illuminated area of one celestial body as seen from another celestial body; phases of the moon are caused by the positions of Earth, the sun, and the moon 5. Eclipse- an event an event in which the shadow of one celestial body falls on another 6. Terrestrial planet- one of the highly dense planets nearest to the sun; Mercury, Venus, Earth, and Mars 7. Hydrosphere- the portion of the Earth that is water 8. Asteroid- a small, rocky object that orbits the sun; most asteroids are located in a band between the orbits of Mars and Jupiter 9. Dwarf planet- a celestial body that orbits the sun, is round because of it’s own gravity, but has not cleared it’s orbital path 10. Gas giant- a planet that has deep, massive atmosphere, such as Jupiter, Saturn, Uranus, or Neptune 11. Nebular Hypothesis- a model for the formation of the solar system in which the sun and planets condense from a cloud (or nebula) of gas and dust 12. Nebula- a large cloud of dust and gas in interstellar space; a region in space where stars are born 13. Comet- a small body of ice, rock, and cosmic dust that follows an elliptical orbit and that gives off gas and dust in form of a tail as it passes close to the sun 14. Exoplanet- a planetlike body that orbits a star other than the sun 15. Perihelion - the point in the path of a celestial body that is nearest to the Sun 16. Aphelion- the furthest point from the Sun 17. Umbras- well defined if they are produced by big and far sources of light or by small and close sources of light 18. Penumbras- partial shadows, when the light is blocked but there is another source of light or when the light from the source is patially blockedII. Section Reviews 1. Explain why objects in the sky appear to move. - The positions of objects in the sky change over time because Earth, and everything else in the universe, is constantly moving. 2. Describe the star that’s closest to the Earth. - The Sun is the closest star to the Earth. The Sun is the brightest object in the sky because it is so close to us. The Sun is an average star. It is not particularly hot or cool and is of average size. It’s diameters is 1.4 million kilometers. The sun has a mass that is about 330,000 times the mass of Earth.
3. Describe the basic structure of the solar system. - the sun is the most important part of our system and makes up nearly 99% of the total mass of the solar system. The eight planets and their moons make up the remaining 1%. The solar system also contains many other smaller objects, such as planets, asteroids, comets, dust, and gas.4. Explain how gravity keeps planets in orbit around the sun. - The gravity of the sun keeps the planets in their orbits. They stay in their orbits because there is no other force in the solar system, which can stop them.5. Explain what happens in a lunar eclipse and what phase the moon is in during a lunar eclipse. - A lunar eclipse occurs when the Moon passes directly behind the Earth into its umbra (shadow). The moon is in the phase of a full moon.6. State the moon’s role in the formation of tides. - The moon’s gravitational pull is the strongest on the side of Earth nearest the moon. On this side, the ocean is pulled toward the moon, so a slight bulge is created. The solid Earth also moves slightly under the moon’s gravity, but the movement of water is more noticeable because it is water.7. List ways in which the 4 terrestrial planets are similar to one another. - The four terrestrial planets are similar to one another because: a. They are relatively small b. Have a solid and rocky surface c. Scientists can study them by using telescopes and other instruments d. Similar compositions: metallic cores (iron-nickel alloys) e. Similar surface features: mountains, canyons, craters8. Identify the only terrestrial planet that supports life. - The only terrestrial planet the supports life is the Earth.9. Explain why the surface of Venus is so hot. - The result is a “runway” greenhouse effect that raises atmosphere temperatures and keeps the surface temperature greater than 700 K. (A greenhouse effect occurs when infrared radiation is absorbed and heat builds up.)10. Describe the features that distinguish a gas giant from a terrestrial planet. - The features that distinguish a gas giant from a terrestrial planet is: a. While the terrestrial planets have a solid surface the gas giants are gas. b. While terrestrial planets are small gas giants are huge. c. While terrestrial planets have metallic cores, the cores of gas giants are rock and ice. d. While terrestrial planets don’t have rings, gas giants do.
11. Explain why Saturn is thought to still be forming. - Scientists think that helium in Saturn’s outer layer is condensing and falling inward. As the helium nears the central core, the gas heats up. When Saturn uses up its atmospheric helium, this process will stop and Saturn will reach a state of equilibrium. Until then, Saturn is considered to still be forming. 12. Explain how our current model of the solar system differs from Ptolemaeus’ model. - It differs from our model because he thought that the Sun, Moon and the planets orbited the Earth, while in reality it was the Earth and other planets that orbited the Sun. 13. What are the phases of the moon? - First Quarter, Waxing Crescent, New, Waning Crescent, Third Quarter, Waning Gibbous, Full, and Waxing Gibbous. 14. How was the moon made? - Incidentally, that big something that hit our earth, causing it to tilt, also knocked a chunk out of it, which became our moon.III. Power point - History of the Astronomy Basically, Aristotle, a Greek philosopher, made the geocentric model, which consists that the sun orbits the Earth in a circle. He also gave the theory about the five elements, which are: fire, earth, water, air, and ether. Then came Claudius Ptolemaeus, an astronomer, and proposed the best geocentric model, explaining the paths of the Sun and Moon, and of the five known planets, supporting Aristotle’s geocentric model. Then Nicolas Copernicus, an astronomer, came and started the scientific revolution. He made the heliocentric model, which consists that the Earth orbits the Sun while it spins around itself. Then Galileo Galilei “The father of science” discovered Jupiter’s satellites, the Milky Way, Neptune and Venus. He also builded a telescope right after hearing about it.
- Laws of Kepler First Law: Law of Orbits- the planets move on elliptical orbits with the Sun in one of the foci. Second Law: Law of Areas- An imaginary line from the center of the Sun to the planet wipes equal areas in equal periods of time. Consequence: The speed of the planet is greatest when the planet is closer to the Sun and least when it if the furthest. Third law: Law of periods- the square of the orbital perion of a planet is directly proportional with the cube of the mean distance from the planet to the Sun.- Sir Isaac Newton He created the law of universal gravitation. Newton was a physicist; he created the laws of motion and created one of the fundamental laws of the universe (Newton’s Law of Universal Gravitation): Every particle in the Universe attracts every other particle with a force that is directly proportional to the product of the masses of the particles and inversely proportional to the square of the distance between them. The magnitude of the gravitational acting on an object of mass m near Earth’s surface is called the weight of an object, given by:W=mg- The Solar System A. Terrestrial Planet Interiors Mercury, Venus, Earth, Mars Highly dense planets nearest to the Sun Similar compositions: metallic cores (iron-nickel alloys) Similar surface features: mountains, canyons, craters B. The Gas Giants Jupiter, Saturn, Uranus, Neptune Heavy, dense atmospheres They are large and have rings. Have many satellites Have a rocky and icy core C. Mercury Extreme temperatures Mercury year (orbits the Sun in 88 days) Mercury day = 59 Earth days No atmosphere and no water
D. Venus Morning and evening star Sulfuric acid atmospheric content Atmospheric pressure 90 times higher than on Earth Spins slowly in the opposite direction than most of the planet No mountains or plains 1 Venus year = 225 Earth days 1 Venus day = 243 Earth days (less than the year)E. Earth Hydrosphere : the water portion of Earth and helps moderate the temperature Magnetosphere: protects the Earth form radiation and high-energy particles Atmosphere: Protects the Earth from radiation and particles, space debris Why does Earth have seasons? - Something very big hit young Earth knocking it off-kilter. So instead of rotating with its axis perpendicular, it rotates 23.45 degrees from its perpendicular. Seasons: - The summer solstice day (around June 21) is the day with the most hours of daylight - The winter solstice day (around December 21) is the day with the fewest hours of daylight - The Vernal and Autumnal equinoxes (March 20, September 22) are the only days with equal amount daylight and nighttimeF. Moon The only natural satellite of the Earth Has craters and dark patches called Maria Why do high tides occur when the moon is new and full? - The sun’s pull is almost as strong as the moon’s so when they work together oceans bulge higher.G. Mars Polar ice caps 2 small satellites: Phobos and Deimos Volcano: Olympus Mons is the largest mountain in the Solar System No plate tectonics Many impact craters Color red due to iron oxide in the soil Strong dust storms which form red large dunes
H. The asteroid belt Between Mars and Jupiter Ceres- the oldest asteroid and a dwarf planetI. Jupiter The largest planet Enormous storms 1 day = 10 Earth days It has 4 satellites discovered in 1610 by Galileo: Ganymede Callisto Io (thin atmosphere, active volcanoes) Europa (may have liquid water under ice)J. Saturn Has the most extensive ring system Made of dust, rock, and ice Planet still in formation until all atmospheric is consumes Radiates 3x more energy than it receives from the SunK. Uranus Thick, gaseous atmosphere Discovered in 1846 Has the most extreme seasons due to its tiltL. Neptune Discovered in 1781 Same characteristics as Uranus Storms similar to JupiterM. Magnetism All magnets have one South pole and one North pole It’s not possible to separate the magnetic poles The magnetism is the effect of the motion of electrons: rotation around the nucleus and the rotation around its own axis.N. Aurora australis/borealis Protons and neutrons impacting the Earth’s atmosphereO. Eclipses The sun eclipse- the moon is in between the Sun and the Earth and the shadow of the moon is projected on the Earth Total eclipse of the Sun- the observer in the shadow (umbra) Partial eclipse of the sun- the observer is in the penumbra Moon eclipse- the moon is in the shadow (umbra) produced by the Earth