Bell Ringer 4.18.18 What is the difference between Geocentric and Heliocentric? Geocentric – Earth centered solar system Heliocentric - Sun centered solar system

Chapters 3 & 4 GSE

Video

Comets, Asteroids, and Meteors Comets contain a nucleus (rock) and they are surrounded by dust and ice Comets have orbits that they follow

comets Comets have an atmosphere called – coma Comets gas tails always points away from the Sun Comets dust tails always follow behind the comet

comets

comets Halley’s comet is one of the most famous comets. It passes Earth every 75-76 years Last appeared 1986 Next appearance 2061

Asteroids Asteroids: Are considered minor planets Or possibly debris from protoplanets Many asteroids are located in the asteroid belt between Mars and Jupiter Average size 1 Km in Diameter

asteroids

meteoroids Meteoroids can be considered ‘space trash’ Size – dust particle to 10 meters in diameter Meteoroids - located in space Meteors – in Earth’s atmosphere (shooting stars) Meteorites – reach Earth’s surface

Man made ‘space trash’ More than 8000 objects have been launched into space. Some have returned to Earth

Rotation and revolution Earth’s rotation about the 23.5 degree tilt from north pole to south pole. A complete rotation takes 24 hours (1 day) Speed at the equator is 1600 km/hr Revolution around the Sun takes 365 days (1 year) to complete the orbit Speed 106,000 km/hr

Rotation and revolution

Seasonal changes (Draw diagram)

12 Zodiac from 88 constellations

Close Do the Northern and Southern hemisphere have the same seasons at the same time? No – Northern and Southern hemisphere have complete opposite seasons

Bring your electronics