Astronomy Notes Notes Created by Harris Middle School with graphics cited. Part 1 Image From: http://www.astronomy-pictures.net/spiral_galaxy.jpg;

Magnitude/luminosity = how bright H-R Diagram: Shows the relationship between color, temperature, magnitude & size of stars. Color = temperature Magnitude/luminosity = how bright Our Sun is a main sequence star. Magnitude Click for Life Cycle of Stars BrainPOP: http://www.brainpop.com/science/space/lifecycleofstars/ Click for Life Cycle of Stars Animation: http://sunshine.chpc.utah.edu/labs/star_life/support/HR_animated_real.html 2 of 11

2. Gravity pulls material into a sphere that becomes dense, hot Black Dwarf Iike our Sun! Nebula 1. Large cloud of gas & dust where stars form. 2. Gravity pulls material into a sphere that becomes dense, hot & ignites. 4. Outer layers come off 5. Collapses to just its core 3. Expands or Explodes! 3 of 11

What is Nebula? A nebula is an interstellar cloud of dust, hydrogen gas, helium gas and other ionized gases. Stars form here.

Stars The Sun An object made of gas that gives off energy mainly hydrogen helium The Sun medium in size & life span compared to other stars primary energy source for all processes on Earth much closer to Earth than any other star! about 4 ½ billion years old

Galaxy A large grouping of stars, gas and dust in space. 3 types 1 2 3 Spiral or Disc – bulge in center & distinctive spiral arms Example: Our galaxy, The Milky Way Our solar system is located within an arm Elliptical – spherical or elongated Irregular- no definite shape. 1 2 3

Light Year A measure of how long it takes light to travel through space in one year. 9 of 11 Image From: http://uniqhorns.com/images/milkyway.gif; Definition: www.thefreedictionary.com

Electromagnetic Spectrum 10 of 11 Electromagnetic Spectrum The range of all the waves that can travel through matter as well as empty space. R O Y G B I V Scientists use different portions of the spectrum to learn about the universe. Ex: light waves can tell us what elements stars are made & if they are moving away or towards other objects, age of space objects or phenomena, temperature and mass http://www.abc.net.au/science/articles/2010/10/07/3012690.htm