1. Studying Space Section 1 Section 1: Viewing the Universe

2. Studying Space Section 1 26.1 board questions What comes to mind when you hear about new astronomical discoveries? Think about what an astronomer does and then draw a picture, with caption, of an astronomer at work. What’s the difference between a refracting and reflecting telescope?

3. Studying Space Section 1 Project Apparent Motions of the Moon Make daily observations of the moon to determine the path and phases of the moon. –Take pictures and a log book of the moon –Every night at the same time –Try to determine the path and the phases of the moon 1/7/2014-2/7/2014

4. Studying Space Section 1 The Value of Astronomy astronomy the scientific study of the universe Scientists who study the universe are called astronomers. In the process of observing the universe, astronomers have made exciting discoveries, such as new planets, stars, black holes, and nebulas. By studying these objects, astronomers have been able to learn more about the origin of Earth and the processes involved in the formation of our solar system.

5. Studying Space Section 1 The Value of Astronomy, continued Studies of how stars shine may one day lead to improved or new energy sources on Earth. Astronomers may also learn how to protect us from potential catastrophes, such as collisions between asteroids and Earth.

6. Studying Space Section 1 Characteristics of the Universe Organization of the Universe The nearest part of the universe to Earth is our solar system. The solar system includes the sun, Earth, the other planets, and many smaller objects such as asteroids and comets. The solar system is part of a galaxy. galaxy a collection of stars, dust, and gas bound together by gravity The galaxy in which the solar system resides is called the Milky Way galaxy.

7. Studying Space Section 1 Characteristics of the Universe, continued Measuring Distances in the Universe astronomical unit the average distance between the Earth and the sun; approximately 150 million kilometers (symbol, AU) Astronomers also use the speed of light to measure distance. Light travels at 300,000 km/s. In one year, light travels 9.46 x 10 12 km. This distance is known as a light-year. Aside from the sun, the closest star to Earth is 4.22 light-years away.

8. Studying Space Section 1 Observing Space Electromagnetic Spectrum electromagnetic spectrum all of the frequencies or wavelengths of electromagnetic radiation. Light, radio waves, and X rays are all examples of electromagnetic radiation. The radiation is composed of traveling waves of electric and magnetic fields that have fixed wavelengths and therefore fixed frequencies.

9. Studying Space Section 1

10. Studying Space Section 1 26.1 board questions 1/8/2014 Answer in complete sentences. You do not have to copy the question. Same paper as yesterday’s board questions. 1.Why do scientists study space? 2.How many years ago did the universe begin? 3.What are the two units for measuring distance in space? 4.What is the longest wavelength humans can see?

11. Studying Space Section 1 Observing Space, continued Visible Electromagnetic Radiation The human eye can see only radiation of wavelengths in the visible light range of the spectrum. The shortest visible wavelength of light are blue and violet, while the longest visible wavelength of light are orange and red. Electromagnetic radiation shorter than wavelengths of violet or longer than wavelengths of red light cannot be seen by humans. –Can’t see shorter than violet or longer than red These invisible wavelengths include infrared waves, microwaves, radio waves (at longer wavelengths than red), as well as ultraviolet waves, X rays, and gamma rays (at shorter wavelengths than blue).

12. Studying Space Section 1 Reading check Which type of electromagnetic radiation can be seen by humans? The only kind of electromagnetic radiation the human eye can detect is visible light.

13. Studying Space Section 1

14. Studying Space Section 1 Observing Space, continued Invisible Electromagnetic Radiation In 1800, the scientist William Herschel discovered infrared, which means “below the red.” –Infrared= below the red  longer than red Infrared is electromagnetic radiation that has waves longer than those of visible light.

15. Studying Space Section 1 The ultraviolet wavelengths, which are invisible to humans, are shorter than the wavelengths of violet light. Ultraviolet means “beyond the violet.” –Ultraviolet= beyond the violet  shorter than violet The X-ray wavelengths are shorter than the ultraviolet wavelengths. The shortest wavelengths are the gamma- ray wavelengths. –Shortest to longest: Gamma ray  x-ray  UV  visible light

16. Studying Space Section 1 Telescopes In 1609, an Italian scientist, Galileo, built a device that used two lenses to make distant objects appear closer and turned it toward the sky. –Galileo built first telescope telescope an instrument that collects electromagnetic radiation from the sky and concentrates it for better observation Telescopes that collect only visible light are called optical telescopes. –Refracting and reflecting

17. Studying Space Section 1 Telescopes, continued Refracting Telescopes refracting telescope a telescope that uses a set of lenses to gather and focus light from distant objects refraction -The bending of light Refracting telescopes have an objective lens that bends light that passes through the lens and focuses the light to be magnified by an eyepiece.

18. Studying Space Section 1 Problems with refracting telescopes the lens focuses different colors of light at different distances causing the image to distort. it is difficult to make very large lenses of the required strength and clarity.

19. Studying Space Section 1 Telescopes, continued Reflecting Telescopes reflecting telescopes a telescope that uses a curved mirror to gather and focus light from distant objects When light enters a reflecting telescope, the light is reflected by a large curved mirror to a second mirror. The second mirror reflects the light to the eyepiece, where the image is magnified and focused. Unlike refracting telescopes, mirrors in reflecting telescopes can be made very large without affecting the quality of the image.

20. Studying Space Section 1 Telescopes, continued The diagram below shows refracting and reflecting telescopes.

21. Studying Space Section 1 Reading check, continued What are the problems with refracting telescopes? Images produced by refracting telescopes are subject to distortion because of the way different colors of visible light are focused at different distances from the lens and because of weight limitations on the objective lens.

22. Studying Space Section 1 Telescopes, continued Telescopes for Invisible Electromagnetic Radiation Scientists have developed telescopes that detect invisible radiation, such as a radio telescope for radio waves. One problem with using telescopes to detect invisible electromagnetic radiation is that Earth’s atmosphere acts as a shield against many forms of electromagnetic radiation. Ground-based telescopes work best at high elevations, where the air is thin and dry.

23. Studying Space Section 1 Space-Based Astronomy Spacecrafts that contain telescopes and other instruments have been launched to investigate planets, stars, and other distant objects In space, Earth’s atmosphere cannot interfere with the detection of electromagnetic radiation.

24. Studying Space Section 1 Reading check Why do scientists launch spacecraft beyond Earth’s atmosphere? Scientists launch spacecraft into orbit to detect radiation screened out by Earth’s atmosphere and to avoid light pollution and other atmospheric distortions.

25. Studying Space Section 1 Space-Based Astronomy, continued Space Telescopes The Hubble Space Telescope collects electromagnetic radiation from objects in space. The Chandra X-ray Observatory makes remarkably clear images using X rays from objects in space, such as remnants of exploded stars. The Swift spacecraft detects gamma rays and X rays from explosions and collisions of objects such as black holes. The James Webb Space Telescope is scheduled to be launched in 2013 to detect near- and mid-range infrared radiation from objects in space.

26. Studying Space Section 1 Space-Based Astronomy, continued Other Spacecraft Since the early 1960s, spacecraft have been sent out of Earth’s orbit to study other planets. The space probes Voyager 1 and Voyager 2 investigated Jupiter, Saturn, Uranus, and Neptune, and collected images of these planets and their moons. The Galileo spacecraft orbited Jupiter and its moons from 1995 to 2003.

27. Studying Space Section 1 Space-Based Astronomy, continued Other Spacecraft, continued The Cassini spacecraft began orbiting Saturn in 2004. In December 2004, the Huygens probe detached from the Cassini orbiter to study the atmosphere and surface of Titan, Saturn’s largest moon. The twin rovers Spirit and Opportunity landed on Mars in January 2004. They confirmed that water had once been present on Mars. In 2008, the Phoenix lander found ice on Mars.

28. Studying Space Section 1 Space-Based Astronomy, continued Human Space Exploration Spacecraft that carry only instruments and computers are described as robotic and can travel beyond the solar system. The first humans went into space in the 1960’s. Between 1969 and 1972, NASA landed 12 people on the moon. The loss of two space shuttles and their crews, the Challenger in 1986 and the Columbia in 2003, have focused public attention on the risks of human space exploration.

29. Studying Space Section 1 Space-Based Astronomy, continued Spinoffs of the Space Program Satellites in orbit provide information about weather all over Earth. Other satellites broadcast television signals from around the world or allow people to navigate cars and airplanes. Inventing ways to make objects smaller and lighter so that they can go into space has also led to improved electronics. Even medical equipment, like the heart pump, have been improved based on NASA’s research on the flow of fluids through rockets.