Astronomy 101: The Solar System

1. Astronomy 101The Solar SystemTuesday, ThursdayTom Burbinetomburbine@astro.umass.edu

2. Course • Course Website: • http://blogs.umass.edu/astron101-tburbine/ • Textbook: • Pathways to Astronomy (2nd Edition) by Stephen Schneider and Thomas Arny. • You also will need a calculator.

3. There is an Astronomy Help Desk that is open Monday-Thursday evenings from 7-9 pm in Hasbrouck 205. • There is an open house at the Observatory every Thursday when it’s clear. Students should check the observatory website before going since the times may change as the semester progresses and the telescope may be down for repairs at times. The website is http://www.astro.umass.edu/~orchardhill/index.html.

4. HW #10, #11, #12, #13, and #14 • Due March 30th at 1 pm

5. What Planet do we know the most about?

6. Earth • The planet we know best • 70% covered with water

7. http://college.cengage.com/geology/resources/protected/physicallab/thelab/interior/index.htmhttp://college.cengage.com/geology/resources/protected/physicallab/thelab/interior/index.htm

9. Earth’s crust • 46.6% O • 27.7% Si • 8.1% Al • 5.0% Fe • 3.6% Ca • 2.8% Na • 2.6% K • 2.1% Mg

10. Earth is made of minerals

11. Mineral • A naturally occurring, homogeneous inorganic solid substance having a definite chemical composition and characteristic crystal structure • ~4,000 known minerals • 100 can be called "common" • 50 are "occasional“ • the rest are "rare" to "extremely rare".

12. Olivine • (Mg, Fe)2SiO4 • Fayalite (Fa) - Fe2SiO4 • Forsterite (Fo) - Mg2SiO4

13. Pyroxenes • Examples: • Enstatite - Mg2Si2O6 • Ferrosilite - Fe2Si2O6 • Augite - (Ca, Na)(Mg, Fe, Al)(Al, Si) 2O6 Augite Ferrosilite

14. Mineral – A naturally occurring, homogeneous inorganic solid substance having a definite chemical composition and characteristic crystal structure • Rock - naturally occurring aggregate of minerals

15. Forming Different Mineralogies • Can be on a planet-scale • Or a few meters to kilometers

16. Some minerals form before other minerals http://www.gly.fsu.edu/~salters/GLY1000/8Igneous_rocks/Slide16.jpg

17. What minerals form? • Depends on the composition of the magma • Depends how quickly the magma cools

18. Types of Rocks • Igneous – rock that solidified from molten or partially molten material • Metamorphic - rock that has changed in composition, mineral content, texture, or structure by the application of heat or pressure • Sedimentary – rock formed from material that was deposited as sediment by water, wind, or ice and then compressed and cemented

19. Igneous Rock http://en.wikipedia.org/wiki/Image:Magma.jpg

20. Metamorphism Quartzite http://en.wikipedia.org/wiki/Image:Quartzite.jpg

21. Sedimentary • Examples of two types of sedimentary rock: limey shale overlaid by limestone http://en.wikipedia.org/wiki/Image:Limestoneshale7342.jpg

22. Rock formed from sediments covers 75-80% of the Earth's land area

23. Oldest rocks on Earth • Oldest dated mineral • zircon mineral (ZrSiO4) with an age of 4.404 billion years enclosed in a metamorphosed sandstone conglomerate in the Jack Hills of the Narryer Gneiss Terrane of Western Australia. • Zircons contain trace amounts of uranium and thorium • Oldest rock on Earth • The Acasta Gneiss in the Canadian Shield in the Northwest Territories, Canada has zircons with an age of 4.031 billion years. • Other rocks may be older (but are still being argued about)

24. Zircon

25. How do we know what’s in the interior of the Earth?

26. How do we know what’s in the interior of the Earth? • Seismic Waves – vibrations created by earthquakes

27. Seismic Waves • P waves – primary waves – (pushing) – travel faster – can travel through anything • S waves – secondary – (side to side) – travel slower – only through solids

28. http://alomax.free.fr/alss/examples/hodo/hodo_example.html

29. Surface Waves • Travel on the surface of the Earth • Love Wave – side by side • http://www.geo.mtu.edu/UPSeis/images/Love_animation.gif • Rayleigh Wave – rolling movement • http://www.geo.mtu.edu/UPSeis/images/Rayleigh_animation.gif • Most of the shaking felt from an earthquake is due to the Rayleigh waves

31. P (primary) waves S (secondary) waves Surface waves: Rayleigh and Love waves

38. Richter Scale • Measures the magnitude of an earthquake • Single number to quantify the amount of seismic energy released by an earthquake. Amplitude of largest displacement • Under 6.0 - At most slight damage to well-designed buildings. Can cause major damage to poorly constructed buildings. • 6.1-6.9 - Can be destructive in areas up to about 100 kilometers across where people live. • 7.0-7.9 - Major earthquake. Can cause serious damage over larger areas. • 8 or greater - Great earthquake. Can cause serious damage in areas several hundred kilometers across.

42. How do we get information? • The precise speed and direction of the waves depends on the composition, density, pressure, temperature, and phase (solid or liquid)

43. Which of these bodies have they used seismic waves to study?

44. How can you study the interior of a planet from space?

45. Density • Density = mass/volume • If the density is higher than the surface rock, there must be denser material in the interior

46. Gravity • If you can measure gravity (force) with a spacecraft as it rotates around a body, you can determine how mass is distributed on the body

47. Magnetic Field • Tells if a planet has a molten metal interior • Magnetic field definition: • a physical field that arises from an electric charge in motion, producing a force on a moving electric charge

48. http://www.youtube.com/watch?v=uj0DFDfQajw

49. http://www.gcsescience.com/pme1.htm

50. Earth’s magnetic field is believed to be caused by the convection of molten iron, within the outer liquid core along with the rotation of the planet Electrons flow http://geomag.usgs.gov/images/faq/Q6.jpg