Space

1. Earth from Mars Space Earth & Environmental Science

2. Universe

3. The universe is commonly defined as the totality of everything that exists, including planets, stars, galaxies, the contents of intergalactic space, and all matter and energy. • According to the prevailing scientific model of the universe, known as the Big Bang, the universe expanded from an extremely hot, dense phase

4. Galaxies

5. Shapes

6. Our Galaxy: Milky Way • The Milky Way galaxy is the spiral galaxy we call home, as do roughly 100 billion other stars. • The Sun is far from the center of the Galaxy, halfway to the edge of the Galaxy along the Orion spiral arm. • The center of the Milky Way As with most other galaxies, there is a super massive black hole there. Not only does it try to eat anything that goes near it, the area around it is a good place for new stars to form.

7. Our location

8. The Sun • The Sun is the star at the center of the Solar System. • It weighs nearly 330,000 times as much as Earth!

9. Sun Facts Continued.. • It is made up of mostly hydrogen and helium gases. • It is 93 million miles from Earth. • It takes 8 minutes and 19 seconds for light to travel from the Sun to the Earth.

10. Energy is produced by Fusion (joining of nuclei)

11. The Sun’s Energy • Electromagnetic Energy- type of energy radiated by the Sun in the form of waves. • Waves- a way for energy to travel from one point to another. • Long wavelength = Low energy. • Short wavelength = High energy.

12. Wavelength and Visible Light

13. What happens to the energy once it reaches the Earth’s atmosphere? -it is taken in as HEAT!

14. Heat • Heat can be transferred by three methods: • Radiation • Convection • Conduction

15. Radiation • Radiation occurs when the Sun’s energy is transferred to the Earth through waves. • The Earth absorbs the energy as heat, warming the planet. • Kitchen Example: Microwave

16. Convection • Convection is the transfer of heat by the physical movement of the heated medium itself. • It occurs in a cyclical motion: hot medium goes up, cold medium goes down. • Occurs in liquids and gases only. • Kitchen Example: - Oven or teapot

17. Conduction • Conduction is heat transfer as a result of direct contact with heated medium without movement of the medium. • Conduction occurs through TOUCH. • Kitchen Example: Stovetop

18. Does the Sun’s energy affect Earth? • Photosynthesis- Plants use the Sun’s energy to make food, which helps them grow.

19. Sun’s energy uses continued… • Solar Power- We use the Sun’s energy to power our homes through Solar Panels.

20. Why the sun makes life on earth possible

21. Earth’s Movements

22. Who orbits what? • Planets in the solar system orbit the Sun? • Actually they orbit the “center of mass” – Called the “barycenter” of the solar system • Barycenter has “smooth” path through galaxy (but Sun/planets “wiggle”) – Earth/Moon system also has a barycenter

23. The revolution of the Earth around the sun • Takes 365.25 days or one year. • Leap year

24. Seasons What two things cause the difference in the seasons? • The angle of the sun’s rays • The length of the days There are two kinds of rays from the Sun: • Direct- occurs when Earth is tilted toward the Sun • Indirect-occurs when Earth is tilted away from the Sun In the Summer, we get the direct rays from the sun and the days are longer. (But we are farther away from the Sun) In the Winter, we get indirect rays from the Sun and the days are shorter. (But we are closer to the Sun)

25. Earth's Precession • Earth's polar axis precesses very slowly over a period of about 23,000 to 26,000 years. The term precession simply refers to a change in the direction of the axis of a rotating object. As this occurs, the pole of the Earth inscribes an arc in the heavens called the precessional arc. Earth's pole aligns with different pole stars throughout its precessional period. Polaris is Earth's current north-pole star. Earth's ~25,000-year precessional cycle is also referred to as "Earth's Great Year."

27. Nutation:(Latin nutare, "to nod") • Nutation is, in astronomy, a small irregularity in the precession of the equinoxes • Nutation superimposes a small oscillation, with a period of 18.6 years and an amplitude of 9.2 seconds of arc, upon this great slow movement. • The cause of nutation lies chiefly in the fact that the plane of the Moon's orbit around the Earth is tilted by about 5°from the plane of the Earth's orbit around the Sun.

28. Rotation What does Rotation mean? Rotation occurs when something is spinning around an axis. What are some examples of things that rotate? Tops, Ballerinas, Figure skaters, cyclones, Tornadoes, a merry-go-round, Earth How do we know that the Earth rotates? • Star trails- trails made with time exposure, circular paths that occur because the planet is moving and not stationary. • Winds curve because of the Earth’s rotation. • Ocean currents curve clockwise in the northern hemisphere, and counterclockwise in the southern hemisphere. • The movement of a pendulum. It does not actually move, it is the Earth moving that causes the pendulum to appear to change the direction of its swing.

29. Night and Day What causes night and day? The rotation of the Earth • The side of the Earth that is facing the sun has daylight, the side of the Earth away from the sun has night. • It takes 23 hours 56 minutes and 4.1 seconds (24 hours) for the Earth to complete one rotation. • The Earth is tilted on it’s axis at a 23.5 degree angle. • The Earth’s tilt in the direction of the North Star. What is another name for the North Star? Polaris • This tilt is what causes our days to get longer in the summer and shorter in the winter. • Because of the Earth’s rotation the sun appears to rise in the east and set in the west.

30. Summary What is the difference between rotation and revolution? Rotation occurs when an object spins around an axis. Revolution occurs when an object spins around another object. What type of movement causes night and day? The Earth’s rotation What type of movement causes the change of seasons? The Earth’s revolution- the angle of the sun, and the length of the day. How do we know that the Earth Rotates? Star trails, pendulum swings, ocean currents, wind currents

31. Moon Phases

32. The moon revolves or orbits the Earth once every 29 days. • We all ways see the same side of the moon because the moon rotates and revolves at about the same speed.

33. Tides • As the moon travels around the earth and as they, together, travel around the sun, the combined gravitational forces cause the world’s oceans to rise and fall, which is called tide.

34. Half of the Moon is always lit up by the sun. As the Moon orbits the Earth, we see different parts of the lighted area. http://www.nasm.si.edu/apollo30th/moontheater/phasepage2.html

35. The revolution of the Moon around the Earth makes the Moon look as if it is changing shape in the sky.  http://btc.montana.edu/ceres/html/birthdayphases.htm

36. This is caused by the different angles from which we see the lighted part of the Moon's surface.  These are called "phases" of the Moon.  http://btc.montana.edu/ceres/html/birthdayphases.htm

37. http://www.niehs.nih.gov/kids/lunar/why_phases.gif

38. The Moon passes through four major shapes during a cycle that repeats itself every 29.5 days.  The phases always follow one another in the same order: New moon First quarter Third quarter Full moon