Honors Astronomy Exam 1 (Chapters 1-5)

the region you can see in the image

consists of the sun, its family of planets, and some smaller bodies, such as moons and comets

small, spherical, non-luminous bodies that orbit a star and shine by reflected light

a self-luminous ball of hot gas that generates its own energy

the average distance from earth to the sun, which is equal to 1.5 x 10^8

distance light travels in one year

a great cloud of stars, gas, and dust held together by the combined gravity of all of its matter

band of stars seen at night in the sky

the name of our galaxy

places where stars are formed from clouds, gas, and dust

billions of galaxies, each containing billions of stars and billions of planetary systems

groups of stars given names of celebrated heroes, gods, and mythical beasts

less formally defined groupings of stars

a system written by Ptolemy that measures the brightness of stars from 1 to 6; the brighter the star the lower the number and vice versa

how bright stars appear to the human eyes observing from earth

the amount of light energy that hits one square meter in one second

spot directly overhead

spot directly below

north to your zenith to south

where the sky meets ground

angle above the horizon

stars that never rise or set

the angle between two lines extending from your eye to the two objects

1/60th of a degree

1/60th of an arc minute

the angular distance from one edge of the object to the other

the weight of the top tends to make it tip over, and this combines with its rapid rotation to make its axis sweep out of the shape of a cone

the turning of a body on its axis (spin)

the motion of a body around a point outside the body (orbit)

the apparent path of the sun against the background of the stars

any planet visible in the evening sky

any planet visible in the sky shortly before sunrise

the point where the sun crosses the celestial equator going northward

the sun at its most northern point

the point where the sun crosses the celestial equinox going southward

the sun at its most southern point

a band around the sky extending 9 degrees above and below the ecliptic

a diagram showing the location of the sun, moon, and planets around the ecliptic and their position above or below the horizon for a given date and time

small changes in Earth’s orbit, precession, and inclination affect Earth’s climate and can cause ice ages

a careful presentation of theory and evidence in a logical discussion

the moon moves through the shadow of the earth

the region of total shadow

the region of partial shadow

the period of total eclipse

the moon orbits eastward around the earth in 27.32 days

a complete cycle of lunar phases takes 29.53 days

the moon is just the right size to cover the bright disk of the sun

the surface of the sun

the higher layers of the sun’s atmosphere

the sun’s outer atmosphere

eruptions on the solar surface

a tiny bit of the photosphere does not completely drown out the fainter corona, which forms a silvery ring of light, with the brilliant spot of photosphere gleaming

the moon’s point of closest approach to earth

the most distant point in the moon’s orbit

a solar eclipse in which a ring of the photosphere is visible around the disk of the moon

the point where the moon passes through the plane of earth’s orbit

the pattern of eclipses repeats every 6585.3 days

Plato concluded that all motion in the sky must be made up of combinations of circles turning at uniform rates

the argument that Earth was imperfect and lay at the center of the universe

the apparent motion of an object because of the motion of the observer

a small circle that the Aristotle model said the earth followed

a large circle that the Aristotle model said the earth slid around

the point in which Ptolemy supposed that the center of the epicycle moved in such that it appeared to move at a constant rate

the sun is the center of the universe

a figure that can be drawn around two points, called the foci, in such a way that the distance from one focus to any point and back to the other focus equals a constant

(a) half of the longer diameter in an ellipse

(e) half the distance between the foci divided by the semimajor axis in an ellipse

a measure of the amount of matter in the object

the force of gravity decreases as the square of the distance between the objects increases

the velocity needed to stay in a circular orbit

the orbit eastward with the rotation of earth and remains above a fixed spot

the balance point of the system

return the orbiting object to its starting point

the velocity needed to leave a bodt

does not return the orbiting object back to its starting point

twice a month, at the new moon and the full moon, the moon and the sun produce tidal bulges that add together and produce extreme tidal changes; high tide is very high and low tide is very low

less extreme tides at the first- and third-quarter moons when the sun and moon pull at right angles to each other; and the sun’s tides cancel out some of the moon’s tides

light made up of both electric and magnetic fields

distance between peaks of the wave

the number of waves that pass a stationary point in one second

a particle of electromagnetic radiation

an array of electromagnetic radiation displayed in order of wavelength

(nm) one billionth of a meter

one-tenth of a nanometer

(IR) non-visible light that your body detects as heat

wavelength bands that that allow visible light, some shorter wavelength infrared radiation, and some radio waves to reach earth’s surface

telescope that uses a lens to gather and focus light

telescope that uses a mirror to gather and focus light

the main lens in a refracting telescope

the main mirror in a reflecting telescope

a piece used to magnify the image and make it convenient to view

color separation

lenses with two components made of different kinds of glass, and thereby bring two different wavelengths to the same focus

telescopes that collect visible light

telescopes that collect radio waves

the ability of a telescope to collect light

the ability of the telescope to reveal fine detail

unavoidable blurring of light

the amount of image blurring due to atmospheric conditions

its ability to make images bigger

the brightening of the night sky by light scattered from artificial outdoor lighting

first device used by astronomers to record images of celestial objects

sensitive light meters used to measure the brightness of individual objects very precisely

(CCDs) a specialized computer chip containing millions of microscopic light detectors arranged in an array about the size of a postage stamp

converted to numerical data

colors represent different aspects on the object such as intensity, rather than visible color

spreading out light according to wavelength

dark or bright lines that cross the spectrum at specific wavelengths

high-speed computers monitor the distortion produced by turbulence in earth’s atmosphere and rapidly alter some optical components to correct the telescope’s image

the laser causes gas in earth’s atmosphere to glow, producing an artificial star

the method of synthesizing a “virtual” large telescope from two or more smaller telescopes

subatomic particles traveling through space at tremendous velocities