Astronomy

1. Astronomy

2. The Moon’s Topography -Impact craters from meteorites are frequent. -Lava flows during cooling blanket the moon.

3. Moon Formation - The leading scientific theory states 100 million years after the Earth formed, a planet sized object collided with Earth sending debris into orbit. https://www.youtube.com/watch?v=mQAdYWcA7ig

4. Moon Phases - Moon revolves around earth reflecting the sun towards earth. – “Dark Side” of the moon because the rotation and revolution are both 27.3 days. Waxing = getting brighter Waning = getting darker

6. Umbra = total shadow Penumbra = partial shadow Eclipses - Lunar eclipses occur when the Earth is located between the Sun and the Moon. - A solar eclipse occurs when the Moon comes between the Sun and Earth, and the Moon’s shadow hits Earth’s surface.

7. Tides Tides are the twice-daily rise and fall of water level that occurs because the Moon’s gravity attracts different parts of the Earth unequally. The two bulges stay in place as the Earth rotates under them. This produces two high tides and two low tides at a given place every day. http://ed.ted.com/on/Akt5TXox

8. Lab: Charting Moon Phases

9. T: Big Bang Theory

10. Scientific Theory • Explanation of natural phenomena. • Supported by evidence through observation. • Tested many times. • Widely accepted in the scientific community. • May change over time with new technology or evidence.

11. Scientific Law • Laws describe how the natural world behaves. • “Law describes what, and theories explain why.” Hubble Telescope Image

12. Universe • Our sun is one of 1,ooo,ooo,ooo stars in the Milky Way Galaxy. • The Milky Way Galaxy is one of 1,000,000,000 galaxies in Universe. Hubble Telescope Image

13. Big Bang - The most widely-accepted scientific theory on the beginning of our universe. • Universe estimated at 13.8 billion years. • Universe started as a dense, hot, super massive ball that exploded in all directions.

14. Supporting Evidence • Other galaxies have a red shift in light showing that they are moving away from us. • Doppler effect explains the change in the wave frequency. • Cosmic background radiation has been discovered from the Big Bang, which is made up of faint radio signals.

15. Topic : Early Astronomy Topic : Early Astronomy

16. Astronomy timeline • Nicolaus Copernicus (1473-1543) – proposed a model of a solar system with sun in the middle (Heliocentric).

17. Astronomy timeline - Johannes Kepler (1571 – 1630) – discovered three laws of planetary motion. - Galileo Galilei (1564 – 1642) – used the first telescope and discovered the moon’s surface was not smooth and the sun had sun spots.

18. Astronomy timeline • Sir Isaac Newton (1642 – 1727) – formulated the law of gravitational attraction. • Escape velocity is 40,000 km/hr for a spacecraft. • Mass and distance determine gravitational attraction.

19. Kepler’s Laws • The planets orbit in an elipse. • Equal area law, planets move faster when they are closer to the Sun and slower farther away.

20. Kepler’s Laws 3. Period of Orbit2 = Distance away from the sun3

21. Topic: Sun and Solar System

22. The Nebular Hypothesis • The most widely accepted scientific theory for the solar system. • developed from a Nebula - a cloud of gas and dust particles. • 4.7 Billion years ago. • First, the heaviest elements contract towards the center of the cloud forming the sun.

23. Second, the nebula began to spin around the sun, and it flattened into a disk.

24. Third, particles in the cloud began to collide & stick together forming planetesimals (small early planets).

25. Evidence - Meteorites. - Hubble telescope has captured other solar systems forming.

26. The Sun • Average-sized star, Middle aged 4.7 billion years old (10 by is expectancy). • 109 x bigger than Earth (332,000 more massive than Earth). • One of over 1,000,000,000 stars in Milky Way Galaxy • Like the cosmos is mainly made up of Hydrogen and Helium (99.9%).

27. Structure of Sun

28. Sun Spots • Occur in chromosphere. • Dark regions due to 1500 kelvin less than surrounding. • Cycles every 11 years.

29. Solar Flares • Occur at sunspots. • Emits lots of energy in the form of UV rays, radio waves and x-rays and forms a solar wind. • Day after larger flares can affect long distance communication. • Causes auroras.

30. Auroras • Aurora Borealis (northern lights) Aurora Australis (southern lights). • Earth’s magnetic shield deflects solar flares to the poles where energized particles create a light show.

32. Nuclear Fusion • Sun produces energy from Nuclear Fusion. • Hydrogen atoms combine to form helium and the extra mass is converted to energy (gamma rays).

33. Topic: Stars

34. Spectroscopy - Study of light’s wavelength. • Can study stars temperature and compostion. • Hubble Telescope

35. Characteristics of Stars • Color of star is due to stars temperature. • Hot stars are towards blue spectrum. • Cold star are towards the red spectrum.

36. Distance to stars • Parallax is used to measure distance. • Nearest stars have the largest angles and distant stars are too small to measure. • Light year (light travels in one year) is 9.5 x 1012 km

37. Stellar Brightness -Apparent magnitude, how bright a star looks from earth. • Factors include distance, temperature and size. - Absolute magnitude, actual brightness adjusted for distance.

38. Hertzsprung-Russel Diagram • Diagram compares magnitude and temperature of stars. • Shows the evolution of stars (i.e. Life Cycle).

39. We categorize planets into 3 groups: • Inner Planets known as Terrestrial(Earth like) • Outer Planets known as Jovian (Jupiter like) • Exo Planets known as Dwarf(very small)

40. Inner Planets The inner planetsare those found closest to the Sun: Mercury, Venus, Earth, and Mars. The inner planets are sometimes called the Terrestrial (Earth-like) planets. This is because all the inner planets have rocky crusts, dense mantle layers, and very dense cores.

41. Outer Planets The outer planetsare those found beyond the asteroid belt: Jupiter, Saturn, Uranus, and Neptune. The outer planets are known as the Jovian (Jupiter-like) planets. They are much larger, are gaseous (outer layer is mostly hydrogen gas), & have a hot liquid core. These planets are less dense, & all four have ring systems.

42. Dwarf Planets The newest group is called dwarf planets: Ceres, Pluto, and Eris. More dwarf planets are expected to be announced in the coming months. The major reason these are considered dwarf planets is the fact that mass of these objects have not cleared the “neighborhood” around their orbit.