OBJECTS IN THE SKY LO: I will describe various objects in the sky SUN: energy(heat & light) from Sun produces Earth's weather Core: center of Sun, nuclear fusion reactions change hydrogen to helium reactions release energy

core temperature 27 million degrees F energy moves from the core to the surface surface temperature 4 million degrees F energy travels through space as electromagnetic waves of light and heat Earth is 93 million miles from Sun, receives only tiny amount of Sun's energy harmful rays are filtered by atmosphere, ozone and Earth's surface Sun is much larger than Earth 840,000 miles diameter Sun is medium sized star SUN (CONT.)

ASTEROIDS: mountains of rock and metal that are found between Mars and Jupiter (asteroid belt) On the first day of January 1801, Giuseppe Piazzi discovered an object which he first thought was a new comet. But after its orbit was better determined it was clear that it was not a comet but more like a small planet. Piazzi named it Ceres, after the Sicilian goddess of grain. Three other small bodies were discovered in the next few years (Pallas, Vesta, and Juno). By the end of the 19th century there were several hundred.

COMETS: chunks of rock and ice that orbit the Sun in long, oval paths a s comets near the Sun, part of the comet begins to melt and turn to vapor which causes a long, visible gas tail streaming behind the comet Halley's Comet orbits the Earth every 76 years. Last seen in 1986, will return in 2061

METEOROIDS: smaller pieces of rock and dust that fly around the solar system, trail and dust of comets METEORS (SHOOTING STAR): meteoroids that pass through Earth's atmosphere; most burn up quickly before hitting Earth's surface METEORITE: if a meteor hits Earth's surface, surviving chunk of rock is called meteorite

STARS: great balls of gas that burn at tremendous temperatures undergo nuclear fusion reaction changing hydrogen to helium Sun is nearest star very bright but seem dim because of their great distance so far away that their distances are measured in light-years the distance it takes light to travel in one year. (moving at 186,000 mps)

CONSTELLATIONS group of stars that appear to form a picture in the sky Orion