Image From: Astronomy Notes Part 1 Notes Created by Harris Middle School with graphics cited.

Size of the planets compared to the Sun Scale model !

The Inner Planets and our moon (The Terrestrial Planets) Scale model !

The Outer Planets compared to the Inner Planets (The Gas Giants) Scale model ! Click:

1. Universe- contains everything that may or may not exist in space 2. Galaxy- system of stars held together by gravity. 3 types: Spiral, Elliptical, and Irregular. Ex: Milky Way 3. Nebula= interstellar cloud of gas 4. Star- self luminous sphere of gas. Ex: sun 5. Planet- celestial object moving in orbit around star. 6. Moon- ex: small object orbits a planet.

Stars 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 1 of 11

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

Hertzsprung-Russell Diagram Chart to classify luminosity & temperature of stars Luminosity- how BRIGHT or DIM star is. (y-axis) Temperature- higher (hotter) temperatures on left, and lower (cooler) temperatures are on right. (x-axis)

Temperature and Color

H-R Diagram

H-R Diagram: Shows the relationship between color, temperature, magnitude & size of stars. Color = temperature Luminosity = how bright Our Sun is a main sequence star. 2 of 11

H-R Diagram

H-R Diagram copy and label in journal as (HOT,COOL) (BRIGHT, DIM) temperature Luminosi ty SUN ______, _______

H-R Diagram ANSWERS copy and label in journal as (HOT,COOL) (BRIGHT, DIM) temperature Luminosi ty SUN BRIGHT HOT ______, _______

Galaxy A large grouping of stars, dust/gas in space 3 types 1.Spiral – bulge in center & distinctive spiral arms Example: Our galaxy, The Milky Way Our solar system is located within an arm 2.Elliptical – spherical or elongated 3.Irregular of 11

Our Solar System Terrestrial Planet: a rocky, INNER planet Mercury closest to the sun no atmosphere full of craters very hot during day; freezing cold at night Venus Similar in size to Earth Hot, thick & poisonous atmosphere Earth – home! Mars known as the “red planet” because of its iron- rich soil 5 of 11

Gas Giant: large, OUTER planet that is made mostly of gases Jupiter largest planet known for its storm, “The Great Red Spot” Saturn known for its ring system Uranus known for blue-green atmosphere Neptune blue-green atmosphere like Uranus Also has a storm, “The Great Dark Spot” 6 of 11

Other Rocky Bodies... Asteroids asteroid belt between Mars & Jupiter small, rocky body that revolves around the Sun Meteoroids – in space (like asteroids), but usually smaller Meteors – (meteor shower); a bright streak of light caused by the rock burning as it streaks through the atmosphere Meteorites – piece of rock that has landed on Earth without completely burning up, possibly making a crater Comet – a body of ice, rock and dust that forms a tail as it gets close to the Sun 8 of 11

Light Year A measure of how long it takes light to travel through space in one year. Image From: Definition: 9 of 11

Electromagnetic Spectrum The range of all the waves that can travel through matter as well as empty space. Image From : Definition: ROYGBI V 10 of 11 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.

Theories on the Origin of the Universe 1.Steady State – has always been the same 2.Oscillating Model - began by expanding, has slowed down & is now contracting 3.Big Bang - *the dominant theory 12 to 15 billion years ago Universe began as a dense point that exploded It rapidly expanded & began to cool down, forming stars, etc. Evidence  discovery of cosmic background radiation  red shift in EM spectrum suggest it is still expanding 11 of 11 Click for Big Bang BrainPOP: