1. Galaxies – Collections of billions of stars and their systems (existing telescopes can currently ‘see’ over 100 billion different galaxies) Spiral - shaped like a disk, usually with a bulge in the center and with arms that spiral outwards as the galaxy rotates. Spiral galaxies tend to contain more middle-aged stars and clouds of gas and dust. Elliptical - Elliptical galaxies contain older stars and very little gas and dust. They can be different shapes ranging from round, to flattened, elongated spheres. Irregular - an undefined shape and has lots of young stars, dust and gas.

2. Galaxies – Collections of billions of stars and their systems (existing telescopes can currently ‘see’ over 100 billion different galaxies) The Milky Way is a spiral galaxy. Our Sun is 28,000 light years from the galactic center, taking about 220 million years to complete an orbit.

3. Sun’s Position in the Universe Click here for a field trip Click here for a field trip through the Universe.

4. Compare the purposes of the tools and the technology that scientists use to study space. telescope visible light (refracting, reflecting) (Earth-based, space-based) radio IR, UV, x-ray, gamma Spectroscope – This is the only one that will be on Thursday’s test. The rest will be done later. satellite probe flyby orbiter lander rover astronaut/space ships and stations

5. spectroscope

6. Sol – our star’s name, hence the phrase ‘Solar System’ Sol’s satellites – Do you know them in order? – a satellite is an object that orbits, or revolves (not rotates), around another object. This artist’s rendition attempts to show the size to scale of each of Sol’s satellites in comparison to Sol. The artist has also included some of the satellites of the planets. Defend: Earth and our moon are both satellites.

7. 8-4.1. “Summarize the characteristics and movements of objects in the solar system (including planets, moons, asteroids, comets, and meteors/meteoroids/meteorites).” Note: You must also now include SSSB and dwarf planets! You took notes on all of these last week. Is your notebook current?

8. Asteroids, comets, meteoroids (review) Rock and ice are the main ingredients of asteroids, comets and meteors. These flying rocks orbit the sun and sometimes come close enough to Earth to see. Asteroid: made of rocky and/or iron-nickel material most are found in an orbit between Mars and Jupiter Some asteroids have other asteroids orbiting them (their own moons)orbiting them Comet: Long, elliptical orbit – usually travel beyond the gas giants like a ball of rock and dirty snow frozen gases and dust begin to heat when near sun and cause a long tail of vaporized gases, dust and debris to flow behind them. Debris remains littered throughout solar systemDebris Meteoroid: usually a piece of comet debris. Meteor: comet debris entering Earth’s atmosphere; usually the size of a grain of sand to a softball meteor burns when falling through the atmosphere; “shooting star” Meteorite: meteor that doesn’t burn up all the way and hits the earth’s surface