Presentation on theme: "Objectives Vocabulary Describe electromagnetic radiation."— Presentation transcript:
1Objectives Vocabulary Describe electromagnetic radiation. Tools of AstronomyObjectivesDescribe electromagnetic radiation.Explain how telescopes work.Describe space exploration.Vocabularyrefracting telescopereflecting telescopeinterferometryspinoff
2Tools of AstronomyTools of AstronomyThe light that comes to Earth from distant objects is the best tool that astronomers can use to learn about the universe.In most cases, there is no other way to study the cosmos except to analyze the light that we receive from it.
3Tools of AstronomyRadiationElectromagnetic radiation consists of waves of electrical and magnetic disturbances.It includes visible light, infrared and ultraviolet radiation, radio waves, microwaves, X rays, and gamma rays.
4Tools of AstronomyRadiationElectromagnetic radiation travels at the same speed and is classified by:Wavelengths—the distance between peaks on a wave.Frequency—the number of waves or oscillations occurring per second.
5Telescopes When exploring space, telescopes have many benefits: Tools of AstronomyTelescopesWhen exploring space, telescopes have many benefits:Detectors can be attached to a telescope to observe all wavelengths, not just visible light.A telescope brings much more light to a focus than the human eye can, allowing the observation of faint objects.Specialized equipment, such as a photometer which measures the 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 that are too faint for the human eye to see.
6Telescopes Refracting and Reflecting Telescopes Tools of AstronomyTelescopesRefracting and Reflecting Telescopes Two different types of telescopes are used to focus visible light.Refracting telescopes, or refractors, are telescopes that use lenses to bring visible light to a focus.Reflecting telescopes, or reflectors, are telescopes that bring visible light to a focus with mirrors.Reflectors make up the majority of telescopes that are in use today.Most major observatories are located in remote, high elevation locations in order to minimize light and atmospheric interference.
7Tools of AstronomyTelescopesRefracting and Reflecting Telescopes
8Telescopes Telescopes at Other Wavelengths Tools of AstronomyTelescopesTelescopes at Other WavelengthsFor all telescopes, the goal is to bring as much radiation as possible to a focus.Interferometry is the process of linking separate telescopes together so that they act as one telescope.This process has been used with radio telescopes for a number of years and is now being applied to other telescopes as well.The detail in the images that they produce improves as the distance between the telescopes increases.
9Satellites, Probes, and Space-Based Astronomy Tools of AstronomySatellites, Probes, and Space-Based AstronomyInstruments often must be sent into space to collect information because:Earth’s atmosphere blocks infrared radiation, ultraviolet radiation, X rays, and gamma rays.When Earth’s atmosphere does allow certain wavelengths to pass through, the images are blurred.It is the only way to make close-up observations and even obtain samples from nearby objects in the solar system.
10Satellites, Probes, and Space-Based Astronomy Tools of AstronomySatellites, Probes, and Space-Based AstronomyThe Hubble Space Telescope (HST) makes observations in visible-light, infrared, and ultraviolet wavelengths.Other space-based telescopes, such as the Far Ultraviolet Spectroscopic Explorer, the Chandra X-Ray Observatory, and the Spitzer Space Telescope, observe other wavelengths that are blocked by Earth’s atmosphere.
11Satellites, Probes, and Space-Based Astronomy Tools of AstronomySatellites, Probes, and Space-Based AstronomySpacecraftSpace-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 directly.More recently, the twin robots Spirit and Opportunity conducted scientific experiments on Mars in 2004.
12Satellites, Probes, and Space-Based Astronomy Tools of AstronomySatellites, Probes, and Space-Based AstronomyHuman SpaceflightExploring the short term effects of space has been accomplished with the space shuttle program, which began in 1981.Since habitation and research began in 2000, a multi-country space station called the International Space Station has been used to study the long-term effects of life in space.
13Satellites, Probes, and Space-Based Astronomy Tools of AstronomySatellites, Probes, and Space-Based AstronomySpinoffsSpinoffs are technologies that were originally developed for use in space programs that have been passed on to commercial industries for common use.More than 1400 different NASA technologies have been incorporated into products ranging from artificial hearts to cordless tools.
14Tools of AstronomySection Assessment1. What is the difference between a reflecting and a refracting telescope?
15Tools of AstronomySection Assessment2. What are the categories of electromagnetic radiation?
16Tools of AstronomySection Assessment3. Identify whether the following statements are true or false.______ Electromagnetic radiation travels at different speeds that are determined by wavelength.______ When applying interferometry, the detail of the images produced improves as the distance between telescopes increases.______ The Hubble Space Telescope is able to observe X rays.______ More than 1400 spinoffs using NASA technologies exist.
18Objectives Vocabulary The MoonObjectivesDescribe the development of exploration of the Moon.Identify features on the Moon.Explain the theories about how the Moon formed.Vocabularyalbedohighlandmare (plural, maria)impact craterejectarayrilleregolith
19The MoonReaching for the MoonPlans for a crewed lunar expedition began in the late 1950s.In 1957 the Soviet Union launched the first satellite, Sputnik I.In 1961, Soviet cosmonaut Yuri A. Gagarin became the first human in space.On May 5, 1961, Alan B. Shepard Jr. became the first American in space as part of Project Mercury followed by the two-person crews of Project Gemini.On July 20, 1969, the Apollo program landed Neil Armstrong and Buzz Aldrin on the Moon, during Apollo 11.
20Reaching for the Moon Lunar Properties Earth’s moon is one of the larger moons in the solar system, especially compared to the size of the planet it orbits.The Moon is relatively farther from Earth than most moons are from the planets they orbit.Earth’s moon is a solid, rocky body, in contrast to the icy composition of the moons of the outer planets.Earth’s moon is the only large moon among the inner planets.
22Reaching for the Moon The Lunar Surface The albedo of the Moon, the amount of sunlight that its surface reflects, is only about 0.07 (7 percent) contrasted with Earth’s average of 0.31 (31 percent).Because the Moon has no atmosphere, surface temperatures can range from 400 K (127°C) in sunlight to 100 K (–173°C) where it is dark.There is no erosion on the Moon—except for surface creep and wear caused by recent impacts—because it has no atmosphere or flowing water.Craters on the Moon are preserved until one impact covers another.
23Reaching for the Moon The Lunar Surface The surface of the Moon consists of several features:The Highlands are lunar regions that are light in color, mountainous, and heavily covered with craters.The Maria (singular, mare) are lunar regions that are dark, smooth plains, which on average are 3 km lower in elevation than the highlands.
24Reaching for the Moon The Lunar Surface The surface of the Moon consists of several features:Impact craters were formed when objects from space crashed into the lunar surface.Ejecta is material blasted out during impacts that fell back to the surface.Rays are long trails of ejecta that radiate outward from some craters.Rilles are meandering, valleylike structures that are found in the Maria.
25Reaching for the Moon Composition The Moon is made up of minerals similar to those of Earth—mostly silicates.The highlands are predominately lunar breccias, which are rocks formed by the fusing together of smaller pieces of rock during impacts.The maria are predominately basalts that contain no water.
26The MoonHistory of the MoonRadiometric dating of lunar rocks from the highlands indicates an age between 3.8 and 4.6 billion years.Regolith is a layer of loose, ground-up rock on the surface of the Moon that formed as a result of the heavy bombardment during its first 800 million years.The maria which are between 3.1 and 3.8 billion years old formed when lava welled up from the Moon’s interior and filled in the large impact basins.
27History of the Moon Tectonics on the Moon? The Moon, like Earth, has a layered structure, which consists of the crust, the upper mantle, the lower mantle, and the core.Although the Moon experiences moderate moonquakes approximately once a year, scientists theorize that the Moon is not tectonically active.That the Moon has no active volcanoes and no significant magnetic field supports this conclusion.
28The MoonHistory of the MoonTectonics on the Moon?
29History of the Moon Formation Theories The capture theory proposes that as the solar system was forming, a large object ventured too near to the forming Earth, became trapped in its gravitational pull, and formed into what is now the Moon.The simultaneous formation theory states that the Moon and Earth formed at the same time and in the same general area, and thus the materials from which they formed were essentially the same.
30History of the Moon Formation Theories The impact theory proposes that the Moon formed as the result of a gigantic collision between Earth and a Mars-sized object about 4.5 billion years ago, when the solar system was forming.
32The MoonSection Assessment1. Match the following terms with their definitions.___ maria___ albedo___ rille___ regolithA. a layer of loose, ground-up rock on the surface of the MoonB. the amount of light a surface reflectsC. dark, smooth plains, which are on average 3 km lower than lunar highlandsD. meandering, valleylike structures on the Moon
33The MoonSection Assessment2. Briefly explain the impact theory.
34The MoonSection Assessment3. Identify whether the following statements are true or false.______ The United States was the first country to launch a human into space.______ There is only one other large moon among the inner planets.______ On the Moon, craters are preserved until one impact covers another.______ Less than 10 percent of the light striking the Moon’s surface is reflected back into space.
36Objectives Vocabulary The Sun-Earth-Moon SystemObjectivesIdentify the relative positions and motions of Earth, the Sun, and the Moon.Describe the phases of the Moon.Explain eclipses of the Sun and Moon.Vocabularyeclipticsummer solsticewinter solsticeautumnal equinoxvernal equinoxsynchronous rotationsolar eclipseperigeeapogeelunar eclipse
37The Sun-Earth-Moon System The relationships between the Sun, Moon, and Earth are important to us in many ways.The Sun provides light and warmth, and it is the source of most of the energy that fuels our society.The Moon raises tides in our oceans and illuminates our sky with its monthly cycle of phases.Every society from ancient times to the present has based its calendar and its timekeeping system on the apparent motions of the Sun and Moon.
38The Sun-Earth-Moon System Daily MotionsThe Sun rises in the east and sets in the west, as do the Moon, planets, and stars as a result of Earth’s rotation.We observe the sky from a planet that rotates once every day, or 15° per hour.
39Daily Motions Earth’s Rotation The Sun-Earth-Moon SystemDaily MotionsEarth’s RotationThere are two relatively simple ways to demonstrate that Earth is rotating.1. A Foucault pendulum, which has a long wire, a heavy weight, and will swing in a constant direction, appears from our point of view to shift its orientation.2. Flowing air and water on Earth are diverted from a north-south direction to an east-west direction as a result of Earth’s rotation in what is known as the Coriolis effect.
40Daily Motions Earth’s Rotation The Sun-Earth-Moon SystemDaily MotionsEarth’s RotationThe length of a day as we observe it is a little longer than the time it takes Earth to rotate once on its axis.Our timekeeping system is based on the solar day, which is the time period from one sunrise or sunset to the next.
41The Sun-Earth-Moon System Annual MotionsThe annual changes in length of days and temperature are the result of Earth’s orbital motion about the Sun.The ecliptic is the plane in which Earth orbits about the Sun.
42Annual Motions The Effects of Earth’s Tilt The Sun-Earth-Moon SystemAnnual MotionsThe Effects of Earth’s TiltEarth’s axis is tilted relative to the ecliptic at approximately 23.5°.As Earth orbits the Sun, the orientation of Earth’s axis remains fixed in space.At one point, the northern hemisphere of Earth is tilted toward the Sun, while six months later it is tipped away from the Sun.As a result of the tilt of Earth’s axis and Earth’s motion around the Sun, the Sun is at a higher altitude in the sky during summer than in the winter.
43Annual Motions The Effects of Earth’s Tilt The Sun-Earth-Moon System Altitude is measured in degrees from the observer’s horizon to the object. There are 90 degrees from the horizon to the point directly overhead, called the zenith of the observer.
44Annual Motions Solstices The Sun-Earth-Moon SystemAnnual MotionsSolsticesAs Earth moves from position 1, through position 2, to position 3, the altitude of the Sun decreases in the northern hemisphere.Once Earth is at position 3, the Sun’s altitude starts to increase as Earth moves through position 4 and back to position 1.
45Annual Motions Solstices The Sun-Earth-Moon SystemAnnual MotionsSolsticesThe summer solstice occurs around June 21 each year when the Sun is directly overhead at the Tropic of Cancer, which is at 23.5° N.The summer solstice corresponds to the Sun’s maximum altitude in the sky in the northern hemisphere.
46Annual Motions Solstices The Sun-Earth-Moon SystemAnnual MotionsSolsticesThe winter solstice occurs around December 21 each year when the Sun is directly overhead at the Tropic of Capricorn which is at 23.5° S.The winter solstice corresponds to the Sun’s lowest altitude in the sky in the northern hemisphere.
47The Sun-Earth-Moon System Annual MotionsSolstices
48Annual Motions Equinoxes The Sun-Earth-Moon SystemAnnual MotionsEquinoxesWhen the Sun is directly overhead at the equator, both hemispheres receive equal amounts of sunlight.The autumnal equinox occurs around September 21, halfway between the summer and the winter solstices when the Sun is directly over the equator.
49Annual Motions Equinoxes The Sun-Earth-Moon SystemAnnual MotionsEquinoxesThe vernal equinox occurs around March 21, halfway between the winter and the summer solstices when the Sun is directly over the equator.For an observer at the Tropic of Cancer or Tropic of Capricorn, the Sun is 23.5° from the point directly overhead during the equinoxes.
50Annual Motions Equinoxes The Sun-Earth-Moon System For a person standing at the x at 23.5º N, the Sun would appear in these positions on the winter solstice, the vernal equinox, and the summer solstice. On the autumnal equinox, the Sun would be at the same altitude as on the vernal equinox.
51The Sun-Earth-Moon System Phases of the MoonThe sequential changes in the appearance of the Moon are called lunar phases.A new moon occurs when the Moon is between Earth and the Sun and we cannot see the Moon because the sunlit side is facing away from us.As the Moon moves along in its orbit, the amount of reflected sunlight that we can see increases until we are able to see the entire sunlit side of the Moon, known as a full moon.Once a full moon is reached, the portion of the sunlit side that we see begins to decrease as the Moon moves back toward the new-moon position.
53Phases of the Moon Synchronous Rotation The Sun-Earth-Moon SystemPhases of the MoonSynchronous RotationSynchronous rotation is the state at which orbital and rotational periods are equal.As the Moon orbits Earth, the same side faces Earth at all times because the Moon has a synchronous rotation, spinning exactly once each time it goes around Earth.
54The Sun-Earth-Moon System Motions of the MoonThe length of time it takes for the Moon to go through a complete cycle of phases is called a lunar month.The length of a lunar month is about 29.5 days, which is longer than the 27.3 days it takes for one revolution, or orbit, around Earth.The Moon also rises and sets 50 minutes later each day because the Moon has moved 13° in its orbit over a 24-hour period, and Earth has to turn an additional 13° for the Moon to rise.
56Motions of the Moon Tides The Sun-Earth-Moon SystemMotions of the MoonTidesThe Moon’s gravity pulls on Earth along an imaginary line connecting Earth and the Moon, creating bulges of ocean water on both the near and far sides of Earth.As Earth rotates, these bulges remain aligned with the Moon.When the Sun and Moon are aligned along the same direction, the result is higher-than-normal tides, called spring tides.When the Moon is at a right angle to the Sun-Earth line, the result is lower-than-normal tides, called neap tides.
57The Sun-Earth-Moon System Solar EclipsesA solar eclipse occurs when the Moon passes directly between the Sun and Earth and blocks our view of the Sun.When the Moon perfectly blocks the Sun’s disk, we see only the dim, outer gaseous layers of the Sun in what is called a total solar eclipse.A partial solar eclipse is seen when the Moon blocks only a portion of the Sun’s disk.
58The Sun-Earth-Moon System Solar EclipsesThe shadow that is cast on Earth consists of two regions.A total eclipse occurs in the inner portion called the umbra, which does not receive direct sunlight.A partial eclipse occurs in the outer portion of the shadow called the penumbra, where some of the Sun’s light reaches.
60Solar Eclipses The Effects of Orbits The Sun-Earth-Moon SystemSolar EclipsesThe Effects of OrbitsThe Moon’s orbit is tilted 5° relative to the ecliptic and usually the Moon passes north or south of the Sun as seen from Earth, during a new moon.A solar eclipse can occur only when the intersection of the Moon and the ecliptic is in a line with the Sun and Earth.
61Solar Eclipses The Effects of Orbits The Sun-Earth-Moon SystemSolar EclipsesThe Effects of OrbitsThe Moon’s distance from Earth increases and decreases as the Moon moves in its elliptical orbit around Earth.Perigee is the closest point in the Moon’s orbit to Earth.Apogee is the farthest point in the Moon’s orbit from Earth.When the Moon is near apogee, it appears smaller, and thus it does not completely block the disk of the Sun, resulting in an annular eclipse.
62The Sun-Earth-Moon System Lunar EclipsesA lunar eclipse occurs when the full Moon passes through Earth’s shadow.A lunar eclipse can happen only at the time of a full moon, when the Moon is in the opposite direction from the Sun.A total lunar eclipse occurs when the entire Moon is within Earth’s umbra.Solar and lunar eclipses occur in almost equal numbers, with slightly more lunar eclipses.
64The Sun-Earth-Moon System Section Assessment1. Match the following terms with their definitions.___ ecliptic___ summer solstice___ winter solstice___ apogeeA. occurs when the Sun is directly overhead at the Tropic of CancerB. the point in the Moon’s elliptical orbit that is the farthest from EarthC. the plane that contains Earth’s orbitD. occurs when the Sun is directly overhead at the Tropic of Capricorn
65The Sun-Earth-Moon System Section Assessment2. Number the lunar phases in the correct order, beginning after the new moon.___ waxing gibbous___ full moon___ waning crescent___ third quarter___ first quarter___ waning gibbous___ waxing crescent
66The Sun-Earth-Moon System Section Assessment3. Identify whether the following statements are true or false.______ A maximum of five eclipses, solar and lunar combined, can occur in a year.______ The Sun will appear at the same altitude in the sky during both the autumnal and vernal equinoxes.______ The Earth has a synchronous rotation.______ To witness a total solar eclipse, you must be inside the umbra of the Moon’s shadow.
68Section 28.1 Study GuideSection 28.1 Main IdeasVisible light, radio waves, infrared and ultraviolet radiation, X rays, and gamma rays are types of electromagnetic radiation.A telescope collects light over a large area, makes time exposures, and can use other instruments to analyze light.Visible-light telescopes can be made using lenses, as in refracting telescopes, or mirrors, as in reflecting telescopes.Space is explored by telescopes, satellites, probes, and humans.
69Section 28.2 Study GuideSection 28.2 Main IdeasThe first step toward exploration of the Moon was the launch of the Soviet satellite Sputnik 1. The American spacecraft Apollo 11 was the first crewed exploration of the Moon.The Moon’s surface has many features that are not present on Earth because the Moon lacks an atmosphere and therefore its surface does not undergo erosion.Scientists have three theories on how the Moon formed—simultaneous formation with Earth, a passing object captured by Earth’s gravity, or as the result of an object colliding with Earth. The collision theory is the most widely accepted.
70Section 28.3 Study GuideSection 28.3 Main IdeasThe entire sky appears to rotate daily because we observe it from a rotating Earth. Our timekeeping system is based on the solar day, the length of day as observed from Earth.Our view of the Sun’s position changes throughout the year as Earth moves in its orbit about the Sun. Seasons occur on Earth because Earth’s axis is tilted.The Moon goes through a cycle of phases each lunar month that correspond to our changing view from Earth of the sunlit side of the Moon.
71Section 28.3 Study GuideSection 28.3 Main IdeasTides are caused by the gravitational attraction of the Moon, and to a lesser extent, the gravitational attraction of the Sun.A solar eclipse occurs when the Moon lies directly between Earth and the Sun. A lunar eclipse occurs when the Moon passes through Earth’s shadow.