PSSC: The Earth Sciences

Size: px

Start display at page:

Download "PSSC: The Earth Sciences"

Cory Hamilton
6 years ago
Views:

1 PSSC: The Earth Sciences Dr. Neil Suits, Assistant Professor of Earth Science Office: Sci 118 Phone: Best times to see me are right after class on Mondays and Fridays also is good.

2 PSSC: The Earth Sciences readings and quizzes First quiz, next Wednesday. 8 th Edition Ch 14: pp Ch 15: scan the chapter, look at the figures and read the captions, know all the planets in the solar system, know the two types of planets, know terms in boldface. Ch16: ; ; Ch 17: ; (mineral formation) 7 th Edition Chapter 14, pages Chapter 15, scan the chapter. Know the planets of the Solar System, know the two types of planets, know terms in boldface Chapter 16, pages ; (Places & Time) ; Moon, etc Chapter 17, pages ; Read Figure Captions;

3 PSSC: The Earth Sciences topics we will cover Time and Place: Where the Earth and Solar System come from. Basic Geology: How rocks and minerals are formed as well as mountains and oceans. We will also look at the geology of Montana, and take a quick tour through the fossil record. Weather and Climate: What is the difference between weather and climate? What controls the weather and what are the facts about Climate Change?

5 ~14 GA (Giga Annum: Billion Years) today

6 ~ 300,000 years after the Big Bang The first map of the Universe. Not homogeneous. Cosmic microwave background (CMB) anisotropy. First detected by the COBE DMR instrument.

7 ~ 100 Billion Stars ~100,000 light years across We would be about here Typical spiral galaxy. Similar to our Milk Way Galaxy ~100,000 light years in diameter

8 We are not alone. About 80 billion galaxies in the observable universe. About 400 billion stars in the Milky Way galaxy (but that may be a bit larger than average) Many (most?) of those probably have planets. How many of those planets are terrestrial (Earth-like?) How many have life?

9 Stars Sun An average star Reference for understanding other stars Massive, dense balls of incandescent gas Powered by nuclear fusion reactions in their core (E = mc 2 ) Origin of stars Gaseous nebula Mostly hydrogen Shock waves induce gravitational collapse Gravitational energy released into higher temperatures and pressures Protostar Accumulation of gases that will become a star

10 Star Birth and Formation: Protostars

11 The internal structure of the Sun

Core Very hot, most dense region Nuclear fusion releases gamma and x-ray radiation Radiation zone Radiation diffuses outward over millions of years Convection

12 Core Very hot, most dense region Nuclear fusion releases gamma and x-ray radiation Radiation zone Radiation diffuses outward over millions of years Convection zone Structured by hot material rising from the interior, cooling, and sinking Upper reaches: visible surface of star Sun surface temp. ~5,800 K Stellar modeling

13 Lifetime of the Sun or any star Our Sun converts about 1.4x10 17 kg of matter to energy each year About 2, lb SUVs! E = mc 2 ( units = kg m 2 /sec 2 = Joules) Lifetime of a star depends on its mass Less massive stars have longer lifetimes More massive stars have shorter lifetimes Born 5 billion years ago Enough hydrogen for another 5 billion years But not every star is like the Sun

14 The Crab Nebula in Lyra Remnants of a supernova

15 .the most violent event ever seen in the universe flashed into view on the morning of March 19th.

16 "This burst was a whopper," said Swift principal investigator Neil Gehrels of NASA's Goddard Space Flight Center in Greenbelt, Md. "It blows away every gamma ray burst we've seen so far.".the March 19 th, 2009 burst had a redshift of 0.94, corresponding to a look-back time of 7.5 billion years several thousand times more than the nearby galaxies. The farthest object ever seen by the naked eye. Most gamma ray bursts occur when massive stars run out of nuclear fuel. Their cores collapse to form black holes or neutron stars, releasing an intense burst of high-energy gamma rays and ejecting particle jets that rip through space at nearly the speed of light like turbocharged cosmic blowtorches. When the jets plow into surrounding interstellar clouds, they heat the gas, often generating bright afterglows. Gamma ray bursts are the most luminous explosions in the universe since the big bang.

Apparent magnitude observed brightness (how bright it looks from Earth) Luminosity actual brightness (how much light the star is actually putting out)

17 Apparent magnitude observed brightness (how bright it looks from Earth) Luminosity actual brightness (how much light the star is actually putting out) Why are some stars bright and others are not? Differences in stellar brightness 1. Amount of light produced by star 2. Size of star 3. Distance to star

temperature Blackbody radiation curves Red: cooler stars Blue: hotter stars

18 What does the color of a Star tell you? Color variations apparent: red, yellow, bluish white Color related to surface temperature Blackbody radiation curves Red: cooler stars Blue: hotter stars Yellow: in between (Sun) Classification scheme Based on temperature: hottest to coolest O, B, A, F, G, K, M Star color ~ star temperature

19 Protostar stage Gravitational collapse Density, temperature and pressure increase 10 million K: fusion ignition temperature Dynamical equilibrium Inward force of gravity Outward pressure of fusion energy Star enters main sequence Life of a star

20 Hertzsprung- Russel Diagram

21 A stars fate depends on its mass

22 Fate of the Sun. First a Red Giant, then a White dwarf within a planetary nebula

23 The Crab Nebula in Lyra Remnants of a supernova

25 Magnetic fields around a sunspot

26 Winds' and Waves on the surface of Sol

27 SUN Hydrogen (74%), some helium (24%) Rocky (Terrestrial) inner planets Silicates with Iron cores The giant Gas planets of the outer solar system Hydrogen, Helium, methane, water, ammonia

28 Planet summary

29 Mercury

30 Venus

33 Earth

34 Mars

35 The Martian ice cap Frozen water?

36 Craters on Mars

37 Olympus Mons ~ 625 km (324 miles) diameter Scarp Height ~ 6 km (4 miles) The largest mountain in the Solar System Why is it so big?

39 Olympus Mons on an overcast day

40 Evidence for water on mars

41 Wind-formed dunes on Mars Atmosphere: 0.7% of the Earth s atmospheric pressure; 95% Carbon Dioxide (CO 2 ), 3% Nitrogen (N 2 ); 1.7% Argon, 0.1% Oxygen (O 2 )

42 View of the surface of Mars from the Martian lander

43 Figure 15.09a Jupiter

44 Figure 15.09b

45 Movie of Jupiter

48 Saturn

51 Titan: moon of Saturn landing400.mov

52 Uranus

54 Neptune

55 Pluto

56 Smaller bodies of the Solar System Comets, asteroids, meteorites Leftover from solar and planetary formation Mass of smaller bodies may be 2/3 of total Solar System mass Bombard larger objects Comet Shoemaker-Levy 9 fragments (bottom) and strikes Jupiter (July 1994)

57 Comet structure Small, solid objects Dirty snowball model Frozen water, CO 2, ammonia, and methane Dusty and rocky bits Comet head Solid nucleus and coma of gas Two types of tails 1. Ionized gases 2. Dust Tail points away from Sun

Earth passing through comet s tail Meteorite Meteoroid surviving to

58 Meteors and meteorites Meteoroids Remnants of comets and asteroids Meteor Meteoroid encountering Earth s atmosphere Meteor showers: Earth passing through comet s tail Meteorite Meteoroid surviving to strike Earth s surface Iron, stony (chondrites and achondrites) or stony-iron

59 Figure 15.19b

60 Figure 15.19a

61 Our moon: Luna

62 Current hypothesis: Luna was formed as a result of an impact by a Mars-sized object in the early stages of Solar System formation.

63 Lunar impact craters

64 Crater Tycho

65 Close up of Tycho

~15 GA. (Giga Annum: Billion Years) today

~15 GA. (Giga Annum: Billion Years) today ~15 GA (Giga Annum: Billion Years) today ~ 300,000 years after the Big Bang The first map of the Universe. Not homogeneous. Cosmic microwave background (CMB) anisotropy. First detected by the COBE DMR