1. NJIT Physics 320: Astronomy and Astrophysics – Lecture XII Carsten Denker Physics Department Center for Solar–Terrestrial Research

2. November 19th, 2003NJIT Center for Solar-Terrestrial Research Problem 18.1 Mass [M Mercury ] Radius [R Mercury ] Moon 0.2230.712 Io 0.2700.744 Europa 0.1480.643 Ganymede 0.4521.078 Callisto 0.3270.984 Titan 0.4091.055 Triton 0.0650.555 Pluto 0.0400.460

3. November 19th, 2003NJIT Center for Solar-Terrestrial Research Problem 18.5

4. November 19th, 2003NJIT Center for Solar-Terrestrial Research Problem 18.7

5. November 19th, 2003NJIT Center for Solar-Terrestrial Research The Terrestrial Planets  Mercury  Venus  Earth  The Moon  Mars

6. November 19th, 2003NJIT Center for Solar-Terrestrial Research Mercury  The four terrestrial planets are small, rocky, and rotate slowly  cf. moons  @ 0.34 AU Kepler’s laws break down  Einstein’s theory of special relativity  Eccentricity of orbit: e = 0.206  Rotation period: T = 58.65 days  Doppler effect  Orbital period: 87.97 days = 3/2 T  Mariner 10 found strong resemblance to the moon  Proximity to Sun and size  very tenuous atmosphere

7. November 19th, 2003NJIT Center for Solar-Terrestrial Research Mercury and Caloris Basin

8. November 19th, 2003NJIT Center for Solar-Terrestrial Research 3-to-2 Spin-Orbit Coupling  Tidal Evolution  Strongest tidal force at perihelion  Energy dissipation due to friction  Circularization of Mercury’s orbit  3-to-2 spin-orbit coupling become instable  1-to-1 resonance of synchronous rotation

9. November 19th, 2003NJIT Center for Solar-Terrestrial Research Venus  Earth’s sister planet  Mass: 0.82 M Earth  Radius: 0.95 R Earth  Retrograde atmospheric circulation (100 m/s at cloud tops near equator)  Hadley cells (“y”-shaped cloud pattern at equator)  Retrograde rotation of the planet  Sidereal rotation period: 243 days  Orbital period: 224.7 days

10. November 19th, 2003NJIT Center for Solar-Terrestrial Research Phases

11. November 19th, 2003NJIT Center for Solar-Terrestrial Research Atmosphere  96.4% carbon dioxide CO 2  3.4% molecular nitrogen N 2  Traces of sulfur dioxide SO 2, water H 2 O, and clouds of sulfuric acid  Temperature 740 K and pressure 90 atm at base of atmosphere  Optically thick in the infrared  Volcanism and/or material delivered by comets and meteorites

12. November 19th, 2003NJIT Center for Solar-Terrestrial Research Greenhouse Effect

13. November 19th, 2003NJIT Center for Solar-Terrestrial Research Surface

14. November 19th, 2003NJIT Center for Solar-Terrestrial Research Earth  Condensation of water forms oceans early in the history of Earth  No conversion of liquid water into vapor!  Carbon dioxide dissolved in water or chemically bound, e.g., carbonate rocks  72% molecular nitrogen N 2  21% molecular oxygen O 2  1% water H 2 O  Traces of argon AR, carbon dioxide CO 2, …  Photosynthesis: CO 2  organic materials + O 2  Increase of greenhouse gases  Annual oscillation of CO 2 due to vegetation cycles  Rainforest  Ozone O 3 layer

15. November 19th, 2003NJIT Center for Solar-Terrestrial Research Structure and Atmosphere

16. November 19th, 2003NJIT Center for Solar-Terrestrial Research Gravity Map of Earth

17. November 19th, 2003NJIT Center for Solar-Terrestrial Research Methane Earth Recent evidence holds that methane (CH 4 ) is second only to carbon dioxide (CO 2 ) in creating a warming greenhouse effect but is easier to control. Atmospheric methane has doubled over the past 200 years, and its smothering potency is over 20 times that of CO 2.

18. November 19th, 2003NJIT Center for Solar-Terrestrial Research Seismic Activity

19. November 19th, 2003NJIT Center for Solar-Terrestrial Research Moon  Moon quakes due to tidal strain (magnitude 1 on Richter scale)  The Moon’s “ringing” after being struck by meteorites  Craters and maria “seas”  Crust is thinner on near side

20. November 19th, 2003NJIT Center for Solar-Terrestrial Research Structure and Formation

21. November 19th, 2003NJIT Center for Solar-Terrestrial Research Radioactive Dating

22. November 19th, 2003NJIT Center for Solar-Terrestrial Research Mars  “Canali” Giovanni Virginio Schiaparelli (1835 – 1910)  Lowell (1855 – 1916) observatory, Flagstaff, AZ  Intelligent life on Mars? LGM? (H. G. Wells “War of the Worlds” broadcasted on October 30th, 1938)  Surface temperature:  140° C to 20° C  95% carbon dioxide CO 2  2.7% molecular nitrogen N 2  Atmospheric pressure: 0.001 atm  Water in layers of permafrost or frozen in polar ice caps  Polar caps predominantly “dry ice” frozen carbon dioxide  General relativity required to explain tilt of Mars spin axis  No large Moon!

23. November 19th, 2003NJIT Center for Solar-Terrestrial Research Atmosphere and Volcanism

24. November 19th, 2003NJIT Center for Solar-Terrestrial Research Deimos and Phobos

25. November 19th, 2003NJIT Center for Solar-Terrestrial Research Ancient Streams and Dunes

26. November 19th, 2003NJIT Center for Solar-Terrestrial Research (Happy) Faces and Hearts

27. November 19th, 2003NJIT Center for Solar-Terrestrial Research Homework Class Project  Continue improving the PPT presentation.  Use the abstract from the previous assignment as a starting point for a PowerPoint presentation.  The PPT presentation should have between 5 and 10 slides.  Bring a print-out of the draft version to the next class as a discussion template for group work  Homework is due Wednesday December 3rd, 2003! It would be good to have your final versions by then in order to have the final grades on December 10 th, 2003.  Exhibition name competition (Final)!

28. November 19th, 2003NJIT Center for Solar-Terrestrial Research Homework  No homework!!!  The Final Exam will be due on December 3 rd, 2003 at the beginning of the lecture.  Please feel free to contact me with any questions concerning the final exam.