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

November 12th, 2003NJIT Center for Solar-Terrestrial Research Lunar Eclipse November 8 th,2003 Eclipsed Moonlight from Connelly's Springs, NC by David Cortner.

November 12th, 2003NJIT Center for Solar-Terrestrial Research Problem 11.1

November 12th, 2003NJIT Center for Solar-Terrestrial Research Problem 11.2

November 12th, 2003NJIT Center for Solar-Terrestrial Research Problem 11.8

November 12th, 2003NJIT Center for Solar-Terrestrial Research Physical Processes in the Solar System  A Brief Survey  Stellar Evolution  Planetary Systems  Tidal Forces  The Physics of Atmospheres

November 12th, 2003NJIT Center for Solar-Terrestrial Research Protoplanetary Disks J. Bally (U. Colorado), H. Throop (SwRI), C.R. O'Dell (Vanderbilt U.), NASA

November 12th, 2003NJIT Center for Solar-Terrestrial Research A Brief Survey TerrestrialJovian Basic form rockygas/liquid/ice Mean orbital distance [AU] 0.39 – – 30.1 Mean surface temperature [K] 200 – – 170 Mass [M  ] – – 318 Equatorial Radius [R  ] 0.38 – – 11.2 Mean density [g cm -3 ] 3.95 – – 1.64 Sidereal rotation period (equator) 23.9 h – 243 d9.8 h – 19.2 h Number of known moons 0 – 28 – 20 Ring systems noyes

November 12th, 2003NJIT Center for Solar-Terrestrial Research Relative Sizes of Planets

November 12th, 2003NJIT Center for Solar-Terrestrial Research Titius–Bode Rule Planet Titius–Bode Distance [AU] Actual Mean Distance [AU] Mercury (4 + 3  0 ) / 10 = Venus (4 + 3  2 0 ) / 10 = Earth (4 + 3  2 1 ) / 10 = Mars (4 + 3  2 2 ) / 10 = Ceres (4 + 3  2 3 ) / 10 = Jupiter (4 + 3  2 4 ) / 10 = Saturn (4 + 3  2 5 ) / 10 = Uranus (4 + 3  2 6 ) / 10 = Neptune (4 + 3  2 7 ) / 10 = Pluto (4 + 3  2 8 ) / 10 =

November 12th, 2003NJIT Center for Solar-Terrestrial Research Solar System Inventory  Sun  Planets  Moons  Asteroid belt (2 – 3.5 AU)  Comets  Kuiper belt (30 AU)  Oort cloud (3000 – 100,000 AU)  Meteoroids, meteor, meteorite, and meteor shower  asteroid and comet debris  Zodiacal light

November 12th, 2003NJIT Center for Solar-Terrestrial Research Thousands of stars, several constellations, a planet and a comet all graced the western horizon over Ujue, Spain just after sunset on April 4th, Because the picture was taken with a fisheye lens, much of the whole night sky is visible. Comet Hale-Bopp, with both tails blazing, appears right of center. The brightest star is Sirius near the edge, well to the left of the constellation Orion. The red star above the belt of Orion is Betelgeuse, while the red star near the center is Aldebaran, to the left of the bright Pleiades star cluster. Many other interesting astronomical objects are visible, e.g., the zodiacal light, which is the diffuse triangular glow in the center. Zodiacal Light

November 12th, 2003NJIT Center for Solar-Terrestrial Research Origin of the Solar System  Gravitational collapse of the original solar nebula  Formation of accretion disk around proto–sun  Planetesimals (terrestrial planets) and additional presence of ice (jovian planets)  More massive planets accumulate extensive primordial H/He atmospheres  Jovian planets have local accretion disks  Capturing of moons  Cometary nuclei either catapulted into Oort cloud or completely ejected from solar system

November 12th, 2003NJIT Center for Solar-Terrestrial Research Tidal Forces

November 12th, 2003NJIT Center for Solar-Terrestrial Research Tidal Forces (cont.)

November 12th, 2003NJIT Center for Solar-Terrestrial Research Tidal Forces (cont.) Earth’s rotation period is lengthening at a rate of s/century and the Moon is drifting away from Earth by 3 to 4 cm/year.

November 12th, 2003NJIT Center for Solar-Terrestrial Research Physics of Atmospheres Under equilibrium conditions, a planet’s total energy content must remain constant. Therefore, all of the energy absorbed by the planet must be reemitted. If not, the planet’s temperature would change with time.

November 12th, 2003NJIT Center for Solar-Terrestrial Research Exosphere The region in an atmosphere where the mean free path of the particles become long enough for them to travel without appreciable collisions is referred to as exosphere.

November 12th, 2003NJIT Center for Solar-Terrestrial Research Exosphere (cont.)

November 12th, 2003NJIT Center for Solar-Terrestrial Research Atmospheric Dissipation and Mixing Gravitational or chemical differentiation

November 12th, 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 November 19 th, 2003 at the beginning of the lecture!  Exhibition name competition!

November 12th, 2003NJIT Center for Solar-Terrestrial Research Homework  Homework is due Wednesday November 19 th, 2003 at the beginning of the lecture!  Homework assignment: Problems 18.1, 18.5, and 18.7!  Late homework receives only half the credit!  The homework is group homework!  Homework should be handed in as a text document!