P LANETS AND MINOR MEMBERS OF THE S OLAR S YSTEM

T ERRESTRIAL P LANETS Mercury Closest to the sun (Temp. ranges from 427° C to -173° C depending on the side) Very dense (large concentration of iron) No atmosphere Venus Covered in thick clouds that prevent light penetration Very geologically active (volcanism & tectonic) Extremely hostile environment (makes studying difficult) Mars Thin atmosphere with strong storms Polar ice caps made of water and carbon dioxide Evidence of ancient water-laden atmosphere is everywhere. (streambeds, islands, valleys)

J OVIAL P LANETS Jupiter Mass is 2.5x greater than all other planets combined Hydrogen, Helium atmosphere that is capable of creating huge storms The Great Red Spot – a storm 3x the size of Earth 28 Moons Io – 1 of 3 volcanically active bodies in the solar system Europa – Global ocean covered by ice with a rocky seafloor (high possibility for life)

J OVIAL P LANETS Saturn Very active atmosphere winds up to 1500 km/hr Large cyclonic storms (like Jupiter’s Great Red Spot) Most complex ring system of all Jovial planets 31 Moons Titan second largest moon in the solar system (larger than Mercury) Substantial atmosphere 1.5 times that on Earth

J OVIAL P LANETS Uranus Axis rotation is nearly parallel with the plane of orbit Appears to be rolling along rather than spinning like a top Neptune Windiest planet in the solar system (winds exceeding 1000km/hr) 13 Moons Triton Large moon that shows retrograde motion (was captured by Neptune’s gravity) 1 of 3 volcanically active bodies in the solar system

P LUTO : P LANET X Mostly consists of frozen gases with some rocky substances. Now known as a member of the Kuiper Belt Region that extends from the orbit of Neptune out to 55 AU. Consists of about 70,000 icy objects with the same composition as Pluto

M INOR M EMBERS OF THE S OLAR S YSTEM Asteroids – small rocky bodies 1000 km diameter to the size of a grain of sand Asteroid belt between Mars and Jupiter Meteoroids – small solid particle that travels through space Meteorite – meteoroid that reaches Earth’s surface Originate from one of three sources: Interplanetary debris that was not captured during the formation of the solar system Material from the asteroid belt The solid remains of comets that once traveled near Earth’s orbit

M INOR M EMBERS OF THE S OLAR S YSTEM Comets – pieces of rocky and metallic materials held together by frozen gases (water, ammonia, methane, carbon dioxide, and carbon monoxide) that vaporize upon approach of the sun Coma – glowing head Tail – vapor trail that extends for millions of kilometers Kuiper Belt Similar to asteroid belt Gravity and collisions cause comets to travel Oort Cloud Spherical shell around the Solar System Millions of comets orbit the sun from great distances

M INOR M EMBERS OF THE S OLAR S YSTEM Halley’s Comet Most famous short period comet Orbital period averages 76 years In 1910 the tail was nearly 1.6 million km long and visible during the daylight hours. In 1986, the European probe Giotto collected data about the shape and surface. Next visit will occur mid 2061

M INOR M EMBERS OF THE S OLAR S YSTEM Oct 8 th Total Lunar Eclipse Oct 22 nd, 23 rd Orionids Meteor Shower Peaks at approx. 20 meteors per hour Produced by dust left behind by Halley’s comet. No moon to interfere with the show (New Moon) so find a dark location after midnight. Look towards the constellation Orion. Oct 23 rd Partial Solar Eclipse Dec 13 th, 14 th Geminids Meteor Shower Considered the best shower Produces up to 120 multicolored meteors / hour at its peak. Waning gibbous moon will block out some, but the Geminids are bright and numerous so find a dark location after midnight. Look towards the constellation Gemini.