Chapter 24.1 SC912N11, SC912E58 SC.912.P.10.16/18, Describe the waves that compose the electromagnetic spectrum Describe what the different types of spectra reveal about stars Explain how the Doppler effect is applies to the motion of stars in relation to Earth. Essential Questions What types of radiation make up the electromagnetic spectrum? 2. How do scientist determine the elements in a star? 1. Vocabulary Words 1. 2. 3. 4. 5. 6. 7. Electromagnetic spectrum Photon Spectroscopy Continuous spectrum Absorption spectrum Emission spectrum Doppler Effect Electromagnetic Radiation Electromagnetic radiation includes gamma rays, X- rays, ultraviolet light, visible light, infrared light, microwaves, and radio waves. The arrangement of these waves according to their wavelengths and frequencies is called the electromagnetic spectrum. All energy, travels through the vacuum of space at the speed of light, or 300,000 kilometers per second. Over a 24 hour day, this equals 26 billion kilometers. Waves Measured from crest to crest Vary in size from kilometers to less than a billionth of a centimeter Colors and Wavelengths Photons A stream of particles Resemble bullets fired from machine gun. Push on matter. Shorter wavelengths have more energetic photons. Blue light has more than red light. Developed by Sir Isaac Newton when he divided light into components. Spectroscopy Spectroscopy is the study of the properties of light that depend on wavelength. Newton produced a rainbow of colors which included all wavelengths of visible light. Spectroscopy Continuous Spectrum Absorption Spectrum Produced by an incandescent Produced when visible light is solid, liquid, or gas under high pressure. Incandescent means to emit light when hot. Spectrum consists of an uninterrupted band of color. Visible light from light bulb is a result passed through a relatively cool gas under low pressure. Appears continuous, but has a series of dark lines running through it. The radiation most stars produce. Spectroscopy Emission Spectrum Produced by a hot gas under low pressure. A series of bright lines of particular wavelengths (depending on gas) When the spectrum of a star is studied, the spectral lines act as “fingerprints.” These lines identify the elements present and thus the star’s chemical composition. Who introduced the field of spectroscopy? Doppler Effect Refers to the perceived change in wave length of a wave that is emitted from a source that is moving away or toward an object. Tells astronomers whether a star is moving towards or away from Earth. Essential Questions 1. What types of radiation make up the electromagnetic spectrum? 2. How do scientist determine the elements in a star? Cooler, darker spots on sun are called___________ 2. Squeezing together of H atoms to create He is ____________ 3. H atoms ripped apart, create electrically charged particles called ______________ 4. How is the sun similar to a bar magnet on Earth? 1. Ch.24.2 SC.912.N.1.1, SC.912.E.5.7, SC.912.E.5.8 Explain how refracting, reflecting, and radio telescopes work. Explain the advantages that space telescopes have over Earthbased telescopes. Vocabulary 1. 2. 3. 4. 5. 6. Refracting telescope Chromatic aberration Reflecting telescope Radio telescope Interferometer Resolving Power Essential Questions 1. How does a refracting telescope produce an image? 2. What advantage does the space telescopes have over the Earth-based telescopes? Refracting Telescopes Galileo considered first person to use a telescope for astronomical observations. Uses a lens to bend or refract light Most important lens in a refracting telescope, the objective lens, produces an image by bending light from a distant object so that the light converges at an area called the focus Focus = central point Refracting Telescopes How it works is that light from an object enters the telescope and passes through the objective lens, which bends the light rays so that they converge at the focus. The rays then travel to the eyepiece, which magnifies the image for the observer. Chromatic Aberration Chromatic (chroma = color) aberration (aberrare = to go astray) Optical defect, short wavelengths bend more so than long wavelengths of refracting telescopes When a refracting telescope is in focus for red light, blue and violet light are out of focus. Problem for astronomers because it weakens the image and produces a halo of color around it. Reflecting Telescope Use a concave mirror that focuses light in front of a mirror, rather than behind it, like the lens. Is a telescopes ability to produce sharper images and finer detail. Properties of Optical telescopes Both reflecting and refracting telescopes have 3 properties that aid astronomers: Light-gathering power 2. Resolving power 3. Magnifying power 1. Radio Telescopes Are huge dishes used to gather and focus radio waves A radio telescope focuses the incoming radio waves on an antenna, which absorbs and transmits these waves to an amplifier, just like a radio antenna. Used to measure the galactic distribution of hydrogen Radio telescopes have poor resolution, when grouped reduces problem. Several radio telescopes wired together, is called an interferometer. Measure the galaxy’s distribution of hydrogen from which stars are made from. Advantage Major advantage of space telescopes versus Earth- based telescopes is they do not have interference from the atmosphere. Essential Questions 1. How does a refracting telescope produce an image? 2. What advantage does the space telescopes have over the Earth-based telescopes? Create a Bingo Board using the vocabulary words provided in the chapter. 4x4 Ch. 24.2 SC912N11, SC912N14, SC912N24, SC912N25, SC912N41 SC912E54 Explain the structure of the sun. Explain how the sun produces energy. Essential Questions 1. What is the structure of the sun? 2. How does the sun produce energy? Structure of the Sun We can divide the sun into four parts: 1. The solar interior 2. The visible surface or photosphere 3. 2 atmospheric layers – chromosphere 4. corona Photosphere Photo = light sphere = a ball Radiates most of the sunlight we see and thought to be the “visible” surface Grainy texture is the result of numerous relatively small, bright markings called granules, which are surrounded by narrow, dark regions. Photosphere/granules Granules are normally the size of Texas Owe brightness to hotter gases that are rising from below. As gas spreads, cooling causes it to darken and sink back into the interior. Each one only survives for 10-20 minutes The combined motion of new granules replacing old ones gives the photosphere the appearance of boiling. Photosphere/granules The up and down movement is called convection. Convection is responsible for the transfer of energy in the uppermost part of the sun’s interior. Energy is transmitted inside the sun through the processes of radiation and convection. The sun’s energy is created in and around the core. Photosphere -revealed by dark lines of its absorption spectrum. -90% of suns surface atoms are hydrogen, almost 10% helium Chromosphere Lies just above the photosphere Relatively thin layer of hot gases a few thousand kilometers thick. Only observed during solar eclipses or with special instruments corona Corona = crown Outer most portion of the solar atmosphere Only visible when the brilliant photosphere is covered. Outer fringe, ionized gases have speeds great enough to escape the gravitational pull of the sun. The streams of protons and electrons that flow from the corona constitute the solar wind. Sun Spots Dark regions on the surface of the photosphere An individual spot contains a black center rimmed by lighter region. Sunspots appear dark because of their temperature, which is about 1500 K less than that of the surrounding solar surface. They are cooler than the rest of the surface. Sunspots increase and decrease in a cycle of 11 years. Sun Spots Solar Flares Most explosive event associated with sunspots Are brief outbursts that normally last about an hour and appear as a sudden brightening of the region above a sunspot cluster. During their existence, solar flares release enormous amounts of energy, much of it in the form of ultraviolet, radio, and X-ray radiation. Solar Flares Most spectacular effects of solar flares on Earth, are the auroras, also called northern and southern lights. Nuclear Fusion The process in which the sun produces energy. The nuclear reaction converts four hydrogen nuclei into the nucleus of a helium atom. During nuclear fusion, energy is released because some matter is actually converted to energy. Nuclear Fusion The sun consumes an estimated 600 million tons of hydrogen each second About 400 million tons are converted to energy. As hydrogen is consumed, the product of this reactionhelium-forms the solar core, which continually grows in size. The sun’s energy is created in the area in and around its core. The Sun In the stable present stage the sun is expected to exist 10 billion years. The sun is 4.5 billion years old. “Middle-Aged” It has 5.5 billion years left at present stage. Essential Questions 1. What is the structure of the sun? 2. How does the sun produce energy? Chandra X-Ray Observatory Studies black holes. Savage Sun Part 2 Quiz Streams of particles coming out of sun that disrupt communications on Earth are 2. What forms when electrons from the solar wind cascade down Earths magnetic field lines and interact with gases in Earth’s atmosphere? 3. What part of the sun can a person on Earth observe during a solar eclipse? 4. At the Solar Neutrino Observatory, what is used to capture neutrinos? 1. Part 2 (25 min) You may use your notes from Part One and Part Two to complete the quiz. This is an individual assignment. No talking or sharing of answers. Anyone who talks will receive a 0% on the quiz.