Review Exercise 2

Review Exercise Solution

Chapter 1: The Foundations of Astronomy

Fill in the blanks

n The __________________ is the totality of all space, time, matter, and energy. universe

n A grouping of stars by humans into recognizable patterns is called a _______________ constellation

n An imaginary sphere surrounding Earth to which all objects were once considered attached is called the ________________________ celestial sphere

n _____________ is measured in degrees north or south of the celestial equator, just as latitude is measured north or south of the Earth's equator. Declination

n _____________ is measured in units called hours, minutes, and seconds, and it increases in the eastward direction. Right ascension

n A __________________ is the distance travels in a year. light year

n The apparent motion of a relatively close object with respect to a more distant background as the location of the observer changes is called

____________________ parallax

n ______________________ is referred to as the Father of Science. Galileo Galilei

Chapter 2: The Copernican Revolution

n The ____________________ model of the universe was based on the assumption that the Sun, moon, and planets all orbit around the Earth. Geocentric

n The ____________________ model of the universe was based on the assumption that Earth and the other planets orbit the Sun. Heliocentric

n The distance from the Earth to the Sun is called the _____________________ astronomical unit

n One early model of the solar system had each planet moving uniformly around a small circle, called an ______________________, whose center moved

uniformly around Earth on a second, larger circle called a _____________________. epicycle, deferent

n The apparent back and forth motion of the planets was difficult for the early astronomers to explain. This motion is called _____________________ motion.

retrograde

Chapter 3: Radiation

n The motion induced change in the observed frequency of a wave is called the ______________ effect. Doppler

n Stars in space that are moving toward us appear ________________ shifted (a color) blue

n Stars in space that are moving away from us appear ________________ shifted (a color) red

n Visible light is one type of electromagnetic radiation. List 2 additional types of electromagnetic radiation

Þ ___________________________

radio, infrared, untraviolet, x rays, gamma rays

Chapter 4: Spectroscopy

Fill in the blanks

n A ______________________ is a device for splitting a bean of radiation into its component frequencies and delivering them to a screen or detector for

detailed study. These devices allow us to obtain information about stars. spectroscope

n This German physicist summarized the observed relationships among the three types of spectra. He formulated three rules that now are named after him.

His name is ____________________________Gustav Kirchoff

n The three types of spectra are

Þ _____________________________ continuous

Þ _____________________________ emission line

Þ _____________________________ absorption line

Chapter 5: Telescopes

Fill in the blanks

n Optical telescopes are designed specifically to collect the wavelengths that are visible to the human eye. Optical telescopes fall into the following 2 basic

categories

Þ _____________________________ reflectors

Þ _____________________________ refractors

n Because the atmosphere is no hindrance to long-wavelength radiation, astronomers have built a number of ground-based ___________________________

capable of detecting these signals from space. One of the largest of this type telescope is in West Virginia.

Radio telescopes

n The main disadvantage of the above type telescope is its relatively poor angular resolution. In some circumstances, however, this limitation can be overcome

with a technique known as ______________________________. This approach uses two or more such telescopes in tandem to observe the

same object at the same wavelength and at the same time. interferometry

n _______________________ telescopes resemble optical telesccopes, but their detectors are designed to be sensitive to radiation of longer wavelengths.

Infrared

n The VLA interferometer is made up of 27 separate dishes spread along a Y-shaped pattern about 30 km acros near Socorro, NM. VLA stands for

_____________________________ Very Large Array

n The _______________________________ space telescope is a joint venture betwen the US and Europe. Is is the largest, most complex, observatory ever

deployed in space. Hubble

n The individual that first proposed an expanding universe is __________________________ LeMaitre.

Chapter 6: The Solar System

n Some characteristics of planets are listed in the left column below. Indicate whether the characteristic, in general, applies to either a terrestrial or jovian

planet by placing a check mark (Ö) in the appropriate column.

Characteristic	Jovian	Terrestrial
Closest to the Sun		Ö
Closely spaced orbits		Ö
Small masses		Ö
Large radii	Ö
No solid surface	Ö
Low density	Ö
Slower rotation		Ö
Few moons		Ö
No rings		Ö

n In 1974, the U.S. spacecraft Mariner 10 came within 10,000 km of the surface of _______________, sending back high resolution images of the planet.

Mercury

n In 1978, the U.S. Pioneer ________________ mission placed an orbiter at an altitude of 15 km above the surface of ________________________ (same

answer both blanks) Venus

n __________________________ is the study of the motions of gravitationally interacting objects, such as planets and stars, applying Newton's laws of motion

to understand their movements. Celestial Mechanics

n Mission scientists often use their knowledge of the above discipline to carry out _________________ maneuvers which can boost an interplanetary probe into

a more energetic orbit and also aid navigation toward the target at no additional cost. slingshot

n A large cloud of interstellar dust is called a ______________________ nebula

n The French mathematician-astronomer Laplace showed mathematically that conservation of _________________________________ demands that nebula

spin faster as they contract. This decrease in size of a rotating mass must be balanced by an increase in its rotational speed. angular momentum

n The _____________________________ theory rests on the old nebular theory investigated by Laplace but combining it with new information about instellar

chemistry to avoid most of the original theory's problems. condenstation

n The ________________________________________ is used to conserve fuel when visiting other planets. The engine is fired once to put the object into the

transfer orbit and then a second time to make the circular orbit. Hohmann Transfer Orbit

n ______________________________ refers to comparing and contrasting the properties of the diverse worlds we encounter to better understand the conditions

under which the planets form and evolve. Comparative Planetology

n The ________________________ belt is located roughly between Mars and Jupiter

Asteroid

n The ____________________________ belt lies outside Neptune's orbit. Kuiper

n The planet closest to the Sun is _______________________ Mercury

n Most celestial objects rotate. _______________________________ is a tendency of an object to keep rotating; it is proportional to the mass, radius, and

rotation speed of the body. Angular momentum

n One of the earliest models of solar sysetm formation dates back to Descartes. It involves a large cloud of gas that began to collapse under its own gravity to

form the sun and planets. This is referred to as _______________________ theory. Nebular

n A currently favored model of solar system formulation combines features of the old theory of Descartes with new information about interstellar dust grains

which acted as condensation nuclei. This theory is called ______________________ theory. Condenstation

n A ______________________________ assist can be used to conserve fuel when travelling between planets. A spacecraft using this technique uses the gravity

of a planet or moon to pull itself around the mass at greater speed. gravitational assist or slingshot

n The ________________________ orbit was first devised by the German scientis Walter Hohmann. It was used in the Cassini Mission. Hohmann Transfer

n The _______________________ theory was first introduced by Andrei Linde. The basic idea involved an infinity of universes and included a false vacuum state.

Bubble

n A _______________________ planet refers to one of the four giant outer planets of the solar system, resembling Jupiter in physical and chemical composition.

Jovian

n Answer any 2 of the following – circle the ones you elect to answer (only 2) ADDED: EXTRA CREDIT IF GET > 2 CORRECT

ð A ______________________________ is a chunk of interpolanetary debris prior to encountering Earth’s atmosphere. meteoroid

ð A bright streak in the sky, often referred to as a “shooting star”, resulting from a small piece of interplanetary debri entering Earth’s atmosphere and heating

air molecules, which emit light as they return to their ground states. ________________ meteor

ð A _______________________ is a small body, composed mainly of ice and dust, in an eliptical orbit about the sun. As it comes close to the Sun, of of its

material is vaporized to form a gaseous head and extended tail. comet

ð Any part of a meteoroid that survives passage through the atmosphere and lands on the surface of the Earth is called a ____________________meteorite