OUR SOLAR SYSTEM

The Sun For each of the elliptical orbits of the planets, the Sun is found at one (or the other!) of the foci 99.85% mass of Solar System Source of solar wind and space weather

Inner Planets “Terrestrial Planets” Rocky Dense Metal cores (iron) Thin, or NO atmosphere

Asteroid Belt “Minor planets” or “planetoids” less than 1000 km across Asteroid Belt between Mars and Jupiter Occasionally run into Earth and other planets (oops) Ida

Outer Planets Large! “Gas Giants” No solid surface May have a small solid core Tumultuous atmospheres - rapid winds, large storms Rotate relatively quickly

Kuiper Belt Disk of debris at the edge of our Solar System Pluto is a KB Object (sorry!) Source of short- period comets Kuiper Belt is found AU from Sun

Oort Cloud Sphere consisting of billions of comets, &dust 50,000 AU from Sun Long-period comets (random time and direction)

Comets Dirty snowballs - small objects of ice, gas, dust, tiny traces of organic material

Comet Parts  As a comet approaches the Sun, their ice SUBLIMATES  This gas and dust forms the COMA  As the comet orbits, the gasses and dust stream behind, forming the TAIL(s)

Inner Planets! “My Very Excellent Mother…..”

Smallest planet Closest to Sun Fastest orbital velocity Large temperature changes: -173 to 427 ºC (-300 to 800 ºF) No atmosphere-lots of craters! Mercury

Venus Nearly the same size as Earth Slowest rotation of any planet (243 days) Spins backwards Extreme greenhouse effect Very thick atmosphere, mostly CO 2 ! Surface pressure is 100 times higher than Earth’s Hotter than Mercury: 377 to 487 C/ 710 to 908 F

Where Do Atmospheres Come From? Volcanism!!!

Venera Images

Pancake Domes on Venus - What formed these features?

Earth 7900 mile (12756 km) diameter 23 degree axis tilt (seasons!) Surface temps –73 to 48 C (-100 to 120F) Thick atmosphere, mild greenhouse effect Liquid water – lots! - at surface

 Very cold: -117 to -27 F  Thin atmosphere: 95% CO2, & 3% N  No liquid water at surface, but features indicate that there once was!  Two small moons: Phobos & Deimos Mars

The Gas Giants

11x Earth diameter Methane, water, ammonia, rock Rocky core – liquid metallic hydrogen – electrical conductor, generates magnetic field Jupiter

Giant Red Spot:  at least 300 years old  3 x size of Earth  Winds up to 400 km / hr

9x the size of Earth Water, methane, ammonia and "rock“ -290 F Rings – 185,00 miles wide /2 mi thick Water ice in rings 56 moons and counting Saturn

Rather chilly in the rings Red: -261 F Blue -333 F Green -298 F Dirty Snow Turquoise= water ice Red = “dirty”

Uranus

4x the size of Earth Blue from methane absorption of red light (atmosphere) atmosphere has mostly hydrogen and helium -350 F at surface Spins on an axis inclined almost 90 degrees

Keplar’s 3rd Law: The further out a planet is from the Sun, the longer its period of REVOLUTION. Uranus is pretty far out there!

Neptune

Ices and rock - 15% H and little He Methane atmosphere (blue!) Uniform through out; small rocky core? Had storm “Great Dark Spot” MIA since Voyager 2 Pretty Good White Spot (Scooter) zipped around every 16 hours…. 4 Rings – unknown composition 13 moons

Pluto

Is Pluto a Planet? YesNo It has always been considered a planet Very small Very elliptical orbit Out of plane of ecliptic Same material as Kuiper belt objects Found other “non-planets” that were larger