SPACE SYSTEMS UNIT Chapters 26 & 30

26.1 Viewing the Universe The Value of Astronomy Astronomy: the scientific study of the universe By observing the universe astronomers have: Made exciting discoveries, such as new planets, stars, black holes, and nebulas Been able to learn more about the origin of Earth and the processes involved in the formation of our solar system Funded by federal agencies (NSF & NASA) as well as private foundations and industries

LT 1: I can describe characteristics of the universe in terms of time, distance, and organization. Cosmology: the study of the origin, properties, processes, and evolution of the universe. Universe began about 14 Billion years ago in one giant explosion, The Big Bang Universe is expanding and is very large and objects within it are very far apart.

Organization of the Universe Earth is in a solar system The Solar System is in a galaxy (Milky Way Galaxy) Galaxy: a collection of stars, dust, and gas bound together by gravity Beyond The Milky Way are billions of other galaxies

Measuring Distances in the Universe Astronomical unit (AU): approximates the average distance between Earth and the sun About 150 million km Light-year: distance between Earth and the sun that light travels in one year Speed of light = 300,000 km/s 9.46 x 1012 km Closest star to Earth (aside from the Sun) is 4.22 light-years away Follow Notes with Skill Builder Activity: Distances in astronomy are difficult for students to comprehend because the distances are so huge. Have students calculate how far (in km) light travels in one year based on the speed of light. Tell them the star Sirius is located 84,321 trillion km from Earth. Have them calculate this distance in light-years. Colors of Light Activity: Shine a flashlight beam onto a white sheet of paper. Put a prism into the path of the beam of light. Turn the prism slightly until the spectrum appears on the paper. Ask students to describe what they see. Ask them: Which color light seems to bend the most and which color bends the least? (Students should see the colors of the rainbow. The prism bends violet the most and red the least.)

LT 2: I can identify the visible and nonvisible parts of the electromagnetic spectrum. Observing Space Electromagnetic Spectrum: all of the frequencies or wavelengths of electromagnetic radiation (EMR) Humans only see Visible EMR Light travels at the same speed, but have different wavelengths which produces the different colors Invisible EMR have shorter wavelengths than Violet or longer wavelengths than Red Discovered by Sir Frederick William Herschel in 1800 with a thermometer Before Notes: Pair/Share Activity Group students into pairs and have them read silently about the electromagnetic spectrum. Then, have one student summarize what types of radiation make up the visible and invisible parts of the electromagnetic spectrum and how astronomers use these forms of energy. Direct the other student to listen to the retelling and point out any inaccuracies or ideas that were left out. Allow students to refer to the text as needed. After Notes: Splitting Light Activity Explain that astronomers use an instrument called a spectrograph to analyze the light from stars. Spectrographs use prisms or diffraction gratings to break up the light. Students can see the spectrum directly through a diffraction grating cut into 3 cm squares. Set up a table lamp with the shade removed. Distribute diffraction gratings to students. Darken the room and turn on the lamp. Direct students to look at the light source through the diffraction grating. Tell them to handle the grating by the edges, as oil from their fingers will clog the openings. Have students use crayons or colored pencils to draw the spectra they see. Student Practice: Exit Slip: Students need to label the Electromagnetic Spectrum

LT 3: I can compare refracting and reflecting telescopes. Telescope: an instrument that collects EMR from the sky and concentrates it for better observation. Reflecting Telescopes Uses mirrors to gather and focus light Light is reflected off of one lens onto a 2nd mirror which then reflects the light to the eyepiece Mirrors can be very large without affecting the quality of the image Refracting Telescopes Use lenses to bend light (refraction) Objective lens gathers light Eyepiece lens magnifies the light Lens focuses different wavelengths of light at different distances which limits the size of the objective lens.

Light Telescopes Nonvisible EMR Telescopes LT 4: I can explain how telescopes for nonvisible electromagnetic radiation differ from light telescopes. Nonvisible EMR Telescopes Each type of EMR must have its own telescope Affected by Earth’s atmosphere Most of these telescopes are in space Hubble Space Telescope Chandra X-ray Observatory Spitzer Space Telescope (infrared telescope) Light Telescopes Reflecting and Refracting Telescopes Largest Reflecting Telescopes are in HI

Other Spacecraft Voyager 1 & 2 Galileo Cassini-Huygens Launched in 1977 Investigated Jupiter, Saturn, Uranus, and Neptune Galileo Orbited Jupiter and its moons from 1995 – 2003 Cassini-Huygens Launched in 1997 and began orbiting Saturn in 2004 Spirit & Opportunity Explore Mars beginning in 2004 Confirmed water had once been on Mars Curiosity Most recent rover sent to Mars Started exploring the surface in Summer 2012