The Sun- Earth- Moon System

1. The Sun- Earth- Moon System Chapter 28

2. Tools of Astronomy Section 28-1

3. Radiation • The radiation from the cosmos that scientists study is electromagnetic radiation • Electromagnetic (EM) radiation consists of electric and magnetic disturbances traveling through space as waves • The human eye can only sense a limited range of wavelengths, which is visible light

4. Radiation • You may be familiar with some forms of EM radiation • UV rays, X rays, infrared, radio waves, microwaves • EM radiation is classified by: • Wavelengths- the distance between peaks on a wave • Frequency- number of waves or oscillations per second

5. Telescopes have many benefits for exploring space: • Detectors can be attached to observe all wavelengths, not just visible light • Telescopes bring more light to focus than the human eye, allowing observation of faint objects • Specialized equipment such as photometer, which measures intensity of visible light, can be used with a telescope • With the aid of imaging devices, telescopes can be used to make time exposures to detect objects are too faint for the human eye to see

6. Telescopes • Two different types of telescopes are used: • Refracting telescopesuse lenses to bring visible light to a focus • The largest lens on a telescope is the objective lens • Telescopes that bring visible light to focus with mirrors are called reflecting telescopes

7. Telescopes • The majority of telescopes used today are reflectors • Most scientific telescopes are located in observatories far from city lights in higher elevations where less atmosphere will blur images

8. Telescopes at other Wavelengths • For all telescopes, the goal is to bring as much EM radiation to a focus • Interferometry is the process of linking separate telescopes together so that they act as one • The detail in the images that they produce improves the distance between the telescopes

9. Satellites, Probes, and Space-Based Astronomy • Astronomers often send instruments into space to collect information for many reasons • Earth's atmosphere blocks infrared radiation, uv rays, X rays, and gamma rays • When earth’s atmosphere does allow wavelengths to pass through, the images are blurred • Scientists can make close up observations and obtain samples

10. Satellites, Probes, and Space-Based Astronomy • The Hubble Space telescope (HST) makes observations in infrared and UV wavelengths • Other telescopes, like Far Ultraviolet Spectroscopic Explorer, the Chandra X-Ray Observatory, and Spitzer Space Telescope observe other wavelengths blocked by atmosphere

11. Spacecraft • Space-based exploration can be achieved by sending spacecraft directly to the bodies being observed • Robotic probes make close-up observations and sometimes land to collect information • The twin robots Spirit and Opportunity conducted experiments on Mars

12. Human Spaceflight • Exploring objects in space has been a top priority, but the effects of space are very intriguing • A multi-country space station called the International Space Station has been inhabited since 2000 to study long-term effects of space

13. Spinoffs • Space exploration has benefited our society in many ways • NASA technologies that have been passed onto commercial industries for use are called spinoffs • More than 1400 technologies have been passed on

14. Section 28.2 The Moon

15. Reaching for the Moon • Plans for lunar exploration began in the 1950s • The first step was taken in 1957 with the launch of the first satellite by the Soviet Union, Sputnik • Soviet cosmonaut Yuri A. Gagarin became the first human in space in 1961 • The US’s Mercury project launched the first American Alan B. Shepard Jr. into space May 5, 1961 • Project Gemini launched 2 person crews into space and on July 20, 1969 the Apollo program landed Neil Armstrong and Buzz Aldrin on the Moon

16. Lunar Properties