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The Essential Cosmic Perspective - Test
(Ch.1, 2, 3, 4, 5) WFU with correct
questions and answers.
How far is a light year? - correct answers.About 10 trillion (10^13) km or actually 9. trillion km Tell me the groups and classifications of the celestial bodies - correct answers.Superclusters, galaxy clusters, galaxy, solar system, planet How far is an AU? - correct answers.From Earth to the sun, or 150 million km How far is a light second? - correct answers.300,000 km How long does it take light to reach Earth from the moon and from the sun? - correct answers.1 second, 8 minutes What do you call asteroids, comets, and other small stuff orbiting stars? - correct answers.Small solar system bodies What is the expansion (of the universe)? - correct answers.The increase in the average distance between galaxies as time progresses How old is the universe? - correct answers.About 14 billion years How far away is the boundary of the observable universe? - correct answers.14 billion light-years How many galaxies are in the observable universe? - correct answers.100 billion
What is the ecliptic plane? - correct answers.The orbit of the Earth How long does it take our solar system to orbit the galaxy? - correct answers.230 million years Constellation - correct answers.a region in the sky celestial sphere - correct answers.an imaginary sphere that the stars and constellations lie on north celestial pole - correct answers.the point directly over Earth's North Pole South Celestial pole - correct answers.the point directly over Earth's South Pole celestial equator - correct answers.projection of Earth's equator into space, makes a complete circle around the celestial sphere ecliptic - correct answers.the path the sun follows as it appears to circle around the celestial sphere once each year. it crosses the celestial equator at 23.5 angle, because that is the tilt of Earth's axis. local sky - correct answers.the sky as seen from wherever you happen to be standing horizon - correct answers.the boundary between the Earth and the Sky zenith - correct answers.the point that lies directly overhead meridian - correct answers.imaginary half-circle stretching from the horizon due south, through the zenith, to the horizon due north. angular size - correct answers.the angle it appears to span in your fuel dog view angular distance - correct answers.the angle that appears to separate 2 objects circumpolar - correct answers.stars near the north celestial pole that do not rise or set. they make counterclockwise circles around the north star. latitude - correct answers.measures north-south positions longitude - correct answers.measures east-west positions summer (June) solstice - correct answers.June 21, is the moment when the Northern Hemisphere is tipped most directly toward the Sun winter (December) solstice - correct answers.December 21, is the moment when the Northern Hemisphere is tipped most directly away from the Sun
apparent retrograde motion - correct answers.occasionally planets reverse course, moving west to east through the zodiac (usually planets move east to west) stellar parallax - correct answers.we view stars from different places in our orbit at different times of the year, nearby stars should appear to shift back and forth against the background of more distant stars. Why do stars rise and set? - correct answers.earth's eastward rotation causes stars to appear to move west Why do we have seasons? - correct answers.earth's tilt of its axis causes sunlight to be distributed differently on earth at different times of the year. When is summer in Northern Hemisphere? - correct answers.June, July, August When is summer in Southern Hemisphere? - correct answers.December, January, February What do phases of the moon depend on? - correct answers.It's position relative to the sun as it orbits earth Wanning Crescent - correct answers. Third Quarter - correct answers. Wanning Gibbous - correct answers. Full Moon - correct answers. Waxing Gibbous - correct answers. First Quarter - correct answers. Waxing Crescent - correct answers. Polaris - correct answers.star closet to northern Celestial Sphere length of a lunar cycle - correct answers.29 1/2 days geocentric model - correct answers.earth-centered Ptolemaic model - correct answers.the geocentric model of the universe developed by Ptolemy in about 150ad. Each planet moved around Earth on a larger orbit while also doing small orbits. The small circle was called an epicycle. The large circle the deferent.
retrograde motion - correct answers.motion that is backward compared to the norm. (clockwise instead of counterclockwise) Caused by "lapping" other planets on our orbital plane. Copernicus - correct answers.went to heliocentric model (Sun centered). Pythagoras - correct answers.taught that the Earth was a sphere in 500 b.c.e. Aristotle - correct answers.observed Earth's curved shadow on the Moon during lunar eclipses as evidence for a spherical Earth. Aristarchus - correct answers.first to propose a heliocentric model. Failed due to the inability to detect parallax. parallax - correct answers.the phenomenon in which the things look different to people placed at different angles from far away. (Think of holding your finger out in front of your face and closing one eye, then the other) Eratosthenes - correct answers.measured the size of the Earth using the Sun-made shadows. What wandering stars did the ancients see? - correct answers.Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn Occam's Razor - correct answers.the simplest solution is generally the right one Tycho Brahe - correct answers.compiled decades worth of data/observations of planetary motion, developed pre-telescopic instruments, was the 1st to record a supernova explosion (giant douchface) azimuth - correct answers.direction around the horizon from due north, measured clockwise in degrees. (N=0, E=90, S=180, W=270) Kepler - correct answers.discovered planetary orbits are ellipses and not circles. Created three laws of planetary motion. ellipse - correct answers.a type of oval that happens to be the shape of bound orbits. focus (foci) - correct answers.one of two special points within an ellipse that lie along the major axis. semimajor axis - correct answers.half the distance across the long axis of an ellipse. Usually referred to as the average distance of an orbiting object, abbreviated "a" in the formula for Kepler's 3rd law. major axis - correct answers.the long axis of an ellipse
ion - correct answers.atoms with a positive or negative charge baryons - correct answers.particles, including protons and neutrons, that are made up of three quarks leptons - correct answers.fermions not made from quarks, such as electrons speed - correct answers.how far an object moves in a certain amount of time (miles per hour) velocity - correct answers.speed plus direction acceleration - correct answers.change in velocity g - correct answers.acceleration of gravity, 9.8 m/ss net force - correct answers.overall force the combined effect of all the individual forces put together. A change in momentum only occurs when the net force is NOT zero. - correct answers. mass - correct answers.amount of matter in an object weight - correct answers.the force that a scale measures when an object is placed on it uniform motion - correct answers.motion in a straight line at constant speed (not accelerating) force - correct answers.anything that can cause a change in momentum Newton's 1st Law - correct answers.unless acted upon by an outside force, a body remains in uniform motion in a straight line. Otherwise known as the Law of Inertia. (more mass = more inertia) Newton's 2nd Law - correct answers.If a net force acts on an object, the object experiences acceleration where: Fnet = ma Fnet = net force m = mass a = acceleration of object Newton's 3rd Law - correct answers.For every action, there is an equal and opposite reaction. If one object exerts a force on a second object, the second object exerts an equal and opposite force on the first. a Newton (unit) - correct answers.1kgm/ss
Four fundamental forces - correct answers.gravitational, electromadnetic, strong (nuclear), weak Characteristics of gravitational force - correct answers.attractive, works w/particles with mass from planetary to cosmic, and is relatively weak Characteristics of electromagnetic force - correct answers.attractive and repellent, works w/particles with a charge from atoms to humans, and is very strong Characteristics of strong force - correct answers.attractive, works w/quarks and baryons at the atomic nuclei level, is the strongest of the forces but only at a very small range momentum - correct answers.the product of an object's mass and velocity angular momentum - correct answers.momentum attributable to rotation or revolution. The angular momentum of an object moving in a circle of radius r is the product of mvr law of conservation of energy - correct answers. The wavelength of a wave is - correct answers.the distance between two adjacent peaks of the wave. How are wavelength, frequency, and energy related for photons of light? - correct answers.Longer wavelength means lower frequency and lower energy. From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation? - correct answers.radio, infrared, visible light, ultraviolet, X rays, gamma rays How many atoms fit across the period at the end of this sentence? - correct answers.millions Compared to the size of its nucleus, the size of an atom is about - correct answers.100,000 times greater Which of the following statements about electrical charge is true? - correct answers.A positive charge and a negative charge will attract each other. Which of the following statements about electrons is not true? - correct answers.Electrons orbit the nucleus rather like planets orbiting the Sun Consider an atom of gold in which the nucleus contains 79 protons and 118 neutrons. What is its atomic number and atomic mass number? - correct answers.The atomic number is 79, and the atomic mass number is 197.
particular star shows the same hydrogen line appearing at a wavelength of 121.8 nm. What can we conclude? - correct answers.The star is moving toward us. If we observe one edge of a planet to be redshifted and the opposite edge to be blueshifted, what can we conclude about the planet? - correct answers.The planet is rotating. Suppose you see two stars: a blue star and a red star. Which of the following can you conclude about the two stars? Assume that no Doppler shifts are involved. (Hint: Think about the laws of thermal radiation.) - correct answers.The blue star has a hotter surface temperature than the red star. Which of the following is least reasonable regarding our perception of color? - correct answers.A banana which appears yellow in white light would appear blue when illuminated by blue light. Currently, the largest optical telescope mirrors have a diameter of - correct answers. m Which of the following is not a good reason to place observatories on remote mountain tops? - correct answers.to be able to observe at radio wavelengths Why do astronomers need different telescope designs to observe across the electromagnetic spectrum? - correct answers.Photons of different energy behave differently and require different collection strategies The largest effective telescope, created by radio interferometry, is the size of - correct answers.Earth Which of the following wavelength regions cannot be studied with telescopes on the ground? - correct answers.x rays and ultraviolet In what part of the electromagnetic spectrum do the biggest telescopes on Earth operate? - correct answers.radio In what wavelength range was interferometry first routinely used? - correct answers.radio What is the angular resolution of the human eye? - correct answers.about 1 arcminute, or 1/60 of a degree Which of the following statements best describes the two principle advantages of telescopes over eyes? - correct answers.Telescopes can collect far more light with far better angular resolution.
What do astronomers mean by light pollution? - correct answers.Light pollution refers to lights from human sources that make it difficult to see the stars at night. The stars in our sky twinkle in brightness and color because of - correct answers.turbulence in the Earth's atmosphere What is the purpose of adaptive optics? - correct answers.It reduces blurring caused by atmospheric turbulence for telescopes on the ground. What is the purpose of interferometry? - correct answers.It allows two or more small telescopes to achieve the angular resolution of a much larger telescope. Which of the following best describes why we say that light is an electromagnetic wave?
- correct answers.The passage of a light wave can cause electrically charged particles to move up and down. Each of the following describes an "Atom 1" and an "Atom 2." In which case are the two atoms different isotopes of the same element? - correct answers.Atom 1: nucleus with 7 protons and 8 neutrons, surrounded by 7 electrons Atom 2: nucleus with 7 protons and 7 neutrons, surrounded by 7 electrons - correct answers. Suppose you built a scale-model atom in which the nucleus is the size of a tennis ball. About how far would the cloud of electrons extend? - correct answers.Several Kilometers Which of the following statements is true of green grass? - correct answers.It absorbs red light and reflects green light. Which of the following conditions lead you to see an absorption line spectrum from a cloud of gas in interstellar space? - correct answers.The cloud is cool and lies between you and a hot star. The following diagram represents energy levels in a hydrogen atom. The labeled transitions (A through E) represent an electron moving between energy levels.Which labeled transition represents an electron that absorbs a photon with 10.2 eV of energy and how much more energy would this electron need to absorb to become completely dislodged from the atom (ionization)? - correct answers.B If an electron at level 1 in a hydrogen atom absorbs 10.2 eV of energy, it moves to level
- What typically happens next? - correct answers.The electron returns to level 1 by emitting an ultraviolet photon with 10.2 eV of energy.
Which of the following is least reasonable regarding cosmic background radiation (CBR)? - correct answers.Data for CBR is collected by pointing telescopes into dark regions of the sky (that do not appear to have any bright objects).
