Tuesday, July 09, 2013 EPOD APOD OPOD Astronomy Review

1. Tuesday, July 09, 2013EPODAPODOPODAstronomy Review

2. 1. Describe the 3 different types of galaxies – what type do we live in? Spiral Elliptical 2. Elliptical galaxies—large, three-dimensional ellipses; ***most common shape **** 1. Spiral galaxies—spiral arms wind out from inner section; some have barred spirals with stars and gas in a central bar

3. 1. Describe the 3 different types of galaxies – what type do we live in? (continued) Irregular • 3. Irregular galaxies—smaller, less common galaxies with various different shapes

4. 2. Describe how our solar system formed, Sun, planets, and other objects. • 1. A nebula of gas, ice, and dust slowly formed in space • 2. A cloud of material in the nebula slowly rotated in space. • 3. Shock waves might have caused the cloud to contract, and the matter was squeezed into less Space. • 4. The cloud became more dense, rotated faster, heated up, and flattened to form a disk • 5. As the cloud contracted, it grew warmer, triggering a nuclear fusion reaction that created the Sun. Short Answer: Stars and planets form from clouds of gas and dust (A Nebula) which exist between the stars that collapse and condense as a result of gravity and become concentrated enough to form stars

5. 3. Describe the difference between a solar and lunar eclipse: Eclipses—when the Earth or the Moon casts a shadow on the other Solar Eclipse Lunar Eclipse . Lunar eclipse - when Earth’s shadow falls on the Moon • Solar eclipse - the Moon moves directly between Earth and the Sun, shadowing part of Earth.

6. 4. What is the difference between rotation and revolution? 1. Rotation— The spinning of Earth around its axis that causes day and night 2. Revolution—Earth’s yearly orbit around the Sun Earth’s orbit is an ellipse, or elongated, closed curve.

7. 5. Describe a meteor, meteoroid, and meteorite. • Small pieces of the old comet’s nucleus 1. Meteor—small meteoroid that burns up in Earth’s atmosphere 2. Meteoroid—name given to small pieces of comet when they move through space 3. Meteorite—meteoroid that strikes Earth

8. 6. Where do most comets come from? • From the Oort Cloud, which is large group of comets surrounding solar system beyond Pluto

9. 7. Draw a diagram of our solar system, include our star, 8 planets asteroid belt, Kuiper belt, and Oort cloud.

10. 8. Describe the difference between the inner planets and the outer planets. • Inner planets: close to sun, warmer, rocky • Outer planets: Much further out from sun, and they are the gas giants

11. 9. What makes Earth a unique planet? • Earth—third planet from the Sun 1. Water exists on surface as solid, liquid, and gas. 2. More than 70 percent of surface covered with water 3. Atmosphere protects surface from most meteors and Sun’s radiation 4. Not too hot not too cold

12. 10. Describe the parallax effect, what is parallax used for? Space measurement 1. Astronomers measure a star’s parallax—shift in its position when viewed from two different angles 2. Distance is measured in light-years—the distance light travels in a year

13. 11. Why do the positions of constellations appear to change over the course of a year? • The Earth is in different positions as it revolves around the sun. Similar to the Earth’s tilt causing the seasons.

14. 12. Describe the process of fusion. • The energy of the Sun is derived from the fusion of H into He***

15. 13. How does red shift support the Big Bang Theory? Big Bang Theory—holds that universe began 13.7 billion years ago with huge explosion that caused expansion everywhere at the same time All galaxies outside the Local Group indicate a red shift in their spectra indicating they are moving away from Earth Starlight moving away from Earth shifts to red end of spectrum The Universe is expanding

16. 14. Describe all the different forms a star may take during its lifetime. Nebula, protostar, dwarf, giant, supergiant, red giant, planetary nebula, nova, super nova, black hole.

17. 14. (continued) Describe all the different forms a star may take during its lifetime. Nebula, protostar, dwarf, giant, supergiant, red giant, nova, super nova, black hole. Nebulae: A diffuse mass of interstellar dust or gas or both, visible as luminous patches or areas of darkness depending on the way the mass absorbs or reflects incident radiation. Protostar: When the gas and dust in a nebula collapses due to gravity and begins the formation of a star.

18. 14. (continued) Describe all the different forms a star may take during its lifetime. Nebula, protostar, dwarf, giant, supergiant, red giant, nova, super nova, black hole. White Dwarf: A star, approximately the size of the earth, that has undergone gravitational collapse and is in the final stage of evolution for low-mass stars, beginning hot and white and ending cold and dark (Black Dwarf) Red Giant: A star in an intermediate stage of evolution, characterized by a large volume, low surface temperature, and reddish hue.

19. 14. (continued) Describe all the different forms a star may take during its lifetime. Nebula, protostar, dwarf, giant, supergiant, red giant, nova, super nova, black hole. Supergiant: A star that is larger, brighter, and more massive than a giant star, being thousands of times brighter than the Sun and having a relatively short lifespan of only about 10 to 50 million years as opposed to around 5 billion years for the Sun. Nova: Collapsing and then exploding star.

20. 14. (continued) Describe all the different forms a star may take during its lifetime. Nebula, protostar, dwarf, giant, supergiant, red giant, nova, super nova, black hole. Supernova: The explosion of a star, possibly caused by gravitational collapse, during which the star's luminosity increases by as much as 20 magnitudes and most of the star's mass is blown away at very high velocity, sometimes leaving behind an extremely dense core. Black Hole: a theoretical massive object, formed at the beginning of the universe or by the gravitational collapse of a star exploding as a supernova, whose gravitational field is so intense that no electromagnetic radiation can escape.

21. 15. What controls the lifestyle of a star? • Its mass therefore it’s temperature • The hotter a star is, the faster it burns its life away.

22. 16. What is a sunspot? • Sunspots—dark • areas cooler than • their surroundings • Temporary features • which come and go • over days, weeks, • or months • b. Increase and decrease in a 10 to 11 year pattern called solar activity cycle • 2. Sunspots are related to intense magnetic fields

23. 17. What causes seasons to change on Earth? • The tilt of the Earth’s axis causes the seasons • Earth’s tilt causes the Sun’s radiation to strike the hemispheres at different angles.

24. 18. Describe the lunar phases. The Moon seems to shine because it reflects sunlight. Moon phases- the different forms the Moon takes in appearance from Earth.

25. 18. (continued) Describe the lunar phases. 1. New moon - when the Moon is between Earth and the Sun and cannot be seen 2. Waxingphases—more of the illuminated half of the Moon that can be seen each night after the new moon

26. 18. (continued) Describe the lunar phases. • a. First visible thin slice of the moon is a waxing crescent. • b. First quarter phase—half the lighted side of the Moon is visible. • c. Waxing gibbous - more than one quarter is visible. • d. All of the Moon’s lighted side is visible during a full moon.

27. 18. (continued) Describe the lunar phases. • 3. Waningphases—less of the illuminated half of the Moon is visible after the full moon. • a. Waning gibbous - starts after a full moon when more than half of the lighted side is still visible • b. Only half the Moon’s lighted side is visible during the third quarter phase. • c. The last visible slice before a new moon is called the waning crescent.

28. 19. What was the first manned-mission to Moon? Who was first to walk on Moon. • Apollo 11 (Eleven) • Neil Armstrong was the first man to walk on the moon

29. 20. What does the H-R diagram measure? • Ejnar Hertzsprung and Henry Russell graphed stars by temperature and absolute magnitude in a H-R diagram