Presentation on theme: "Long ago, in a galaxy far, far away…"— Presentation transcript:
1Long ago, in a galaxy far, far away… AstronomyLong ago, in a galaxy far, far away…
2Actually, the galaxy isn’t that far away. In fact, we live in it Actually, the galaxy isn’t that far away. In fact, we live in it. It’s called the Milky Way.The Milky Way is a spiral galaxy.Our Solar System is located on one of the arms
3A galaxy is a large group of stars, gas, and dust held together by gravity. Galaxies also include:PlanetsMoonsAsteroidsComets
4There are three major types of galaxies EllipticalIrregularSpiral
5Now, onto Earth…Earth spins on an axis, an imaginary line going through the poles.Earth spinning on it’s axis is called rotation.Spinning a top is an example of rotation.Our axis is tilted at a 23.5 degree angle.
6Rotation It takes about 24 hours, or one day for Earth to rotate once. Rotation is what causes night and day.When we face the sun, it is day, when we are facing away from the sun, it’s night.Is it night or day in Utah?
7Revolution Revolution is when an object orbits another object. An orbit is a path around another object.The moon revolves around the Earth and the Earth revolves around the sun.What does it mean when someone says, “The world doesn’t revolve around you?”
8Orbits The Earth orbits the Sun. The moon orbits Earth. All planets orbit the Sun.Even Haley’s Comet has an orbit.
9What causes Seasons? Answer: The tilt of the Earth’s axis. When the Northern Hemisphere is tilted toward the sun, it is summer.While the Northern Hemisphere is in summer, the Southern Hemisphere is in winter.When the Southern Hemisphere is in fall, what season is the Northern Hemisphere in?
11SolsticesThe solstice is the day when the Sun reaches its greatest distance north or south of the equator.The summer solstice is June 21 or 22.The winter solstice is December 21 or 22.
12EquinoxesThe equinox occurs when the Sun is directly above the Earth’s equator.The spring equinox is March 21 or 22.The fall equinox is September 22 or 23.
13Quiz TimeCan you name the seasons?What causes the seasons?
14The Moon The moon rotates in its axis and revolves around Earth. We only see one side of the moon because it takes the same amount of time to revolve as it does to rotate.The moon appears to change shape as its position to the Earth and Sun changes.
15Earth only sees the side of the moon with the arrow. It takes the moon 27.3 days to revolve around the Earth and 27.3 days to rotate on its axis once.
16Phases of the MoonWaxing means the moon looks like it is getting larger.Waning means the moon looks like it is getting smaller.A full moon is when it looks like we see all the moon.We are really only seeing the half of the moon that is facing us.
21Phases of the Moon Like the Sun, the moon rises from east to west. The moon does not produce its own light.It reflects light from the Sun.It takes 29.5 days for the moon to complete a cycle, but it takes 27.3 days for it to revolve around the Sun.The reason these numbers are different it because it takes the moon 2 extra days to catch up with the Earth’s revolution.
22Tides Tides are caused by the gravitational pull of the moon. There are two high tide and two low tides daily.They occur every 12 hours.
23What is an Eclipse?An eclipse is where the Earth or the moon temporarily block the sunlight from reaching each other.We don’t have eclipses all the time because the moon, Earth, and Sun have to be lines up exactly.The Earth’s orbit and the moon’s orbits are not on the same plane, so this doesn’t happen very often.