Published on January 21, 2008
Viewing the UniverseChap. 26: Sect. 1: Viewing the Universe Chap. 26: Sect. 1 Why is it important to us?: Why is it important to us? Studying how stars shine may lead to improved or new energy sources. Astronomers may learn to protect us from potential catastrophes such as collisions with asteroids. We can learn more about the origin of the Earth and the formation of our solar system and other objects. Slide3: Astronomy: scientific study of the universe Cosmology: the study of the origin, properties, processes and evolution of the universe Big Bang: Theory that the universe began about 14 billion years ago in a giant explosion. The explosion hurled matter in all directions Organization of the Universe: Organization of the Universe Closest part to us is the solar system. It includes the sun, Earth, other planets and many smaller objects. The solar system is part of a galaxy. Galaxy: large collection of stars, dust and gas bound together by gravity What galaxy do we reside in? Measuring Distance: Measuring Distance The universe is so large that our units of measurements are too small to measure it. Because of this we use… Astronomical Unit (AU): the average distance between the Earth and the sun; approximately 150 million kilometers Electromagnetic Spectrum: Electromagnetic Spectrum Electromagnetic Spectrum: all of the wavelengths of electromagnetic radiation The human eye can only see radiation of wavelengths in the visible light range. Shorter wavelengths Longer wavelengths Telescopes: Telescopes Telescope: an instrument that collects electromagnetic radiation from the sky and concentrates it for better observation. Optical telescopes: only collect visible light (these were the first telescopes) Who was the first person to use a telescope? Optical Telescopes: Optical Telescopes Refracting Telescopes Telescope that uses a set of lenses to gather and focus light from distant objects. Lenses are clear objects that bend light . This process is called refraction. In this telescope, the light passes through the lens and is magnified by an eyepiece. One inconvenience of it is that the lens focuses different colors of light at different distances. Optical Telescopes (cont.): Optical Telescopes (cont.) Reflecting Telescopes Uses a curved mirror to gather and focus light from distant objects. Light is reflected by a large curved mirror to a second mirror and then to the eyepiece, which is a lens that magnifies and focuses the image. The mirrors of these telescopes can be made very large without affecting the image. So…these telescopes can be made larger and gather more light than refracting telescopes. Space-Based Astronomy: Space-Based Astronomy Spacecrafts that contain telescopes and other instruments have been sent to study distant objects. These are robotic spacecrafts (no humans aboard). Some methods for space-based astronomy are: Space telescopes Other spacecrafts Human space explorations Space Telescopes: Space Telescopes Hubble Space Telescope: launched to collect electromagnetic radiation from objects in space Chandra X-ray Observatory: makes clear images using X-rays from objects in space Compton Gamma Ray Observatory: no longer in space but detected gamma rays from objects Space Telescopes: Space Telescopes Spitzer Space Telescope: launched in 2003 to detect infrared radiation from objects in space James Webb Space Telescope: will be launched in 2011 and will detect infrared radiation Galaxy M81 Debris circling the star Fomalhaut nebula IC 1396 Nebula: cloud of gas and/or dust newborn star: HH46-IR Other Spacecraft: Other Spacecraft Used since early 1960’s. In 1977, Voyagers 1 & 2 investigated Jupiter, Saturn, Uranus, Neptune and their moons. Galileo (‘95-2003): orbited around Jupiter and its moons. Cassini-Huygens: studied Saturn and its moon, Titan. Voyager 1 Human Space Exploration: Human Space Exploration Crewed spacecrafts haven’t gone beyond the Earth’s moon. The first humans went to space in the 1960’s. The loss of Challenger (1986) and Columbia (2003) have increased awareness of the risks of human space exploration. Colombia ready for launch in 2001. It was the first shuttle to orbit the Earth in 1981. Bonus Benefits: Bonus Benefits Satellites provide weather information and broadcast television signals. Making objects smaller and lighter for space exploration has led to improvement in electronics such as radios and televisions. Studying the flow of fuel in rockets has helped improve heart pumps.