Astronomy Exam #1

the earth is closest to the sun in which month of the year?

January

which of the following places is most likely not to be differentiated?

Jupiter

which of the following types of telescopes can be used only above the Earth's atmosphere?

X-ray telescopes

what does an astronomer use to measure the power outlet of a star?

[luminosity = brightness x 12.57 x (distance)^2] the larger a star is the more energy it puts out and the more luminous it is

what relatively recent event shows that impacts continue to happen in our solar system even today?

a comet hit the planet Jupiter in 1994

which of the following has the greatest average energy of random atomic and molecular motion?

a cube of the sun

in a radio telescope, the role that the mirror plays in visible-light telescopes is played by...?

a large metal dish, antenna

a graduate student is trying to follow the weather on Jupiter for her PhD thesis. To see the big weather patterns in the upper atmosphere of the planet, she needs to have excellent resolution. What type of telescope would be best for her to use?

a large reflector located in orbit above the Earth's atmosphere

in a bad late-night science fiction film, a villain is using a large collection of rare radioactive atoms as energy for a weapon to threaten the good guys. The atoms have a half-life of 1 hour. The villian has 4 kilograms of the radioactive material now, and he needs a minimum of 1 kg for his weapon to work . After how much time will the weapon no longer be a threat?

a little after 2 hours

what happens as an electron falls from a higher level to a lower level in an atom?

a photon is given off

which of the following is not an advantage that a reflector telescope has over a refractor telescope?

a reflector doesn't have to deal with the twinkling of stars, as a refractor does

the Van Allen belt...?

a region of trapped charged particles in the Earth's magnetosphere

To break up light into the component colors that it contains, astronomers use a device called:

a spectrometer

refracting telescope

a telescope in which a large biconvex lens causes light rays to converge to focus, forming an image magnified by a biconvex eye piece

one piece of evidence that can help astronesr sort out how the planets in our solar system formed is...?

finding circumstellar disks of material around nearby stars

What phase of the Moon must it be to have a lunar eclipse?

full moon

You are an astronomer who wants to study a faint star in the process of being born, which gives off most of its faint radiation in the infra-red. Which of the following would NOT be a step you would want to take?

heat your telescope, so its delicate optics are not cold

an educated guess in science is known as a scientific...?

hypothesis

You are alone in a large, completely dark auditorium on Earth. What kind of telescope should I use from the other side of the auditorium to detect the electromagnetic radiation emitted by your body?

infra-red

when an atom has lost one or more electrons, it is said to be...?

ionized

inner planets are made mostly of rock and metal because...?

it was so hot where the inner planets formed that the lighter materials evaporated

ground state

state of lowest energy in which the electrons systematically fill all the orbits from those nearest the nucleus outward to some larger orbit containing the outermost electrons

zenith

that point, on any given observers celestial sphere, that lies directly above him

we see different constellations at different times of the year because...?

the Earth revolves around the sun once per year

of the following, which has the highest resolution?

the Very Long Baseline Array of Radio Telescopes, stretching from the Virgin Islands to Hawaii

the moon is heavily cratered, but the Earth which lives next door, is not. Why?

the active geology and weather on Earth destroy traces of impacts over millions of years

a graduate student in geology who grew up in Florida gets to accompany her research professor to the North Pole. What will be different at the North Pole from the way she remembers the sky in Florida?

the celestial pole is overhead, the celestial equator is on the horizon, the way the stars rise or set

absorbtion spectrum

the characteristic pattern of dark lines or bands that occurs when electromagnetic radiation is passed through an absorbing medium into a spectroscope

right ascension

the coordinate for measuring the east-west positions of celestial bodies; the angle measured eastward along the celestial equator from the vernal equinox to the hour circle passing through a body Astronomical equivalent to longitude

When a knowledgeable amateur astronomer tells you that she has a 14-inch telescope, what does the number 14 refer to?

the diameter of the primary lens or mirror

Newton's reformulation of Kepler's third law allows us to measure the masses of bodies in orbit around each other, if we can measure:

the distances and periods of revolution

why do astronauts float around in the shuttle instead of falling

the rules newton developed for gravity only how on Earth, not once you get into space

resolution

the smallest angle between close objects that can be seen clearly to be separate, separate two point sources into separate images

how does the sun influence the tides that we experience on Earth?

the sun also raises tides on earth, but its effect is smaller than that of the moon

the point in the sky directly above your head at any given time is called...?

zenith

Which of the following was not done Galileo Galilei?

explaining retrograde motion with heliocentric hypothesis

according to the geometric view, everything in the heavens had to go around the Earth, which was the center of the universe. What objects did Galileo discover with his telescope that clearly didn't go around the Earth?

moons around the planet Jupiter

when a planet, in its orbit, is closer to the sun, it...?

moves faster than average

the prefix kilo added to the unit of measure means to...?

multiply that unit of measure by 1000

what phase of the moon must it be to have a solar eclipse?

new moon

tycho brache

no telescope, but accurate geometric observation instruments, assembled masses of data about mars and other known planets, theory of the solar system: stationary Earth, moo and sun revolve

on which of the planets could a human being step out of a spacecraft and survive without any protective gear?

none

solar eclipse

occurs when the moon passes between the Earth and Sun, obscuring the view of the sun

lunar eclipse

occurs when the moon passes through Earth's shadow

An astronomy textbook, when printed out, weighs four pounds on the surface of the Earth. After finishing your course, you are so tired of the book, you arrange for NASA to shoot it into space. When it is twice as far from the center of the Earth than when you were reading it, what would it weigh? (Note, assume that the book has been moving away from the Earth, not falling freely around it.)

1 lb

which is the following numbers has the same meaning as 8670?

8.67 x 10^3

precession

A slow motion of Earth's axis that traces out a cone over a period of 26,000 years the slow conical motion of the Earth's axis of rotation, caused by attraction of the sun and moon, and to a smaller extent, of the planets, on the equatorial bulge of the Earth

Your friend, a graduate student in astronomy, is giving you a special tour of the local observatory. You notice that you are viewing the image from the big telescope from underneath the primary mirror; the beam of light has come through a small hole in the main mirror to an eyepiece below. This telescope uses what focusing arrangement?

Cassegrain focus

a constellation shaped like the letter "W" in the northern sky is named...?

Cassiopia

johannes kepler

German astronomer who first stated laws of planetary motion (1571-1630) discovered that planets move in orbits shaped like an eclipse, a line between a planet and the sun covers equal areas in equal times , how long a planet takes to go around the Sun is related to the radius of the planet's orbit

the largest part of the Earth is its...?

Mantle

the planet closest to the Sun in the solar system is...?

Mercury

the planet closest to the sun in the solar system is...?

Mercury

the star that its currently closest to the North Celestial pole is...?

Polaris

retrograde motion

The apparent motion of the planets when they appear to move backwards (westward) with respect to the stars from the direction that they move ordinarily.

an astronomer observes two ordinary stars. The first one turns out to be twice as hot as the second. This means that the first one radiates...?

about 16 times the energy of the second

a dashing romanian count asks his sweetheart to marry him. she says she will give him her reply when the moon is full. If he asked when the moon was at first quarter, how long will he have to wait?

about a week

Which planet in the solar system has not been examined by spacecraft instruments that have either flown by or orbited them?

all have been examined

a friend of yours tells you about a report he has read in a tabloid newspaper. They claim that on the dark side of the moon, which is never in sunlight, there is a secret base of aliens who cannot stand light, and who send UFO's to Earth under the cover of darkness. Ignoring the UFO claim for a moment, what is the scientific error in this story?

all sides of the moon are illuminate by sunlight in the course of a month, there is no dark side

we now know that the orbit of a stable planet around a star like the Sun is always in the shape of...?

an eclipse

An eccentric billionaire wants to build a mansion in a location on Earth where the effect of the seasons is the least pronounced -- where summer and winter are not that different. Where should his personal astronomer advise him to build?

at the equator

why do different types of atoms give off or absorb different spectral lines?

because the spacing of the energy levels is different in different atoms

spectroscope

breaks the light from a single material into its component colors the way a prism splits white light into a rainbow

what does an astronomer use to measure the temperature of a star?

by looking at the star's color and its spectrum, brightness tells us how bright the star is and the luminosity can be determined from the apparent brightness and the distance

how did Eratosthenes measure the size of the Earth?

by measuring the height of the Sun in the sky on the same day in two cities at different latitudes

the average temperature on planet Earth is higher than you would expect just from the heating of sunlight alone. What is the explanation for this?

carbon dioxide in the atmosphere caused the greenhouse effect

ancient astronomers divided the sky into regions containing distinct groups of stars called...?

constellations

the 88 sectors into which astronomers today divide the celestial sphere are called...?

constellations

what is one way that astronomers have actually gotten an idea of the age of the surfaces of terrestrial planets other than the Earth?

counting craters

according to Kepler's third law, there is a relationship between the time a planet takes to revolve around the sun and its...?

distance from the sun

a light year

distance light travels in one year

which of the following statements about the force of gravity is false?

its strength is inversely proportional to the mass- the more mass, the less gravity

in the northern hemisphere, the altitude of the North Star is always roughly equal to the...?

latitude of the observer

we have two waves of light, A and B. A has a higher frequency than wave B. Then wave B must have...?

longer wavelengths

an astronomer discovers a new star and wants to measure its temperature. She would typically do this by...?

making a black body curve and finding the wavelength of the peak

astronomical unit

mean distance between the center of the Earth and the center of the Sun

what does an astronomer use to measure the mass of a star or planet?

measure the orbits of double star systems, called binaries Newton's law of motion allows astronomers to calculate masses of both stars by measuring their orbits with considerable accuracy

an important way that scientists have been able to study the interior of the Earth is by...?

measuring how seismic waves are transmitted through the Earth

what does an astronomer use to measure the speed with which a star us moving towards or away from Earth?

measuring the extent to which their light is stretched into the lower frequency, red part of spectrum, Doppler effect- change in wave frequency during the relative motion between a wave source and its observer

newton

proposed that all objects in the universe pulled on each other trough gravity, reason why planets move in orbits and why objects fall to the Earth

Not all wavelengths of electromagnetic radiation can penetrate the Earth's atmosphere. Of the following types of waves that come from space, which one are you likely to be able to detect most easily from our planet's surface:

radio waves of the wavelengths that carry FM radio

When a star or galaxy is moving away from us, we observe the Doppler effect by seeing the lines in its spectrum

red-shifted

scientific results must be...?

reproducible

all the planets (without exception)

revolve around the sun in the same direction

regions where the continents or the sea floor are pulling apart are called...?

rift zones

If you want to locate someone precisely on the surface of the Earth, you specify her exact latitude and longitude. If you want to locate a star precisely on the sky, you need to specify its exact:

right ascension and decimation

what does an astronomer use to measure the composition of a star?

spectroscopy-an object's spectrum can determine the wavelength

the process of breaking light down into its component colors creates a....?

spectrum

Scientists now understand that the Earth consists of layers, with the densest materials in the core. What allowed the differentiation of the Earth's layers to happen?

the early Earth must have been so hot it was like a liquid and heavier things sank to the middle

Why is there a 4-minute difference between the solar day and the sidereal day?

the earth is going around the sun in the course of a year

Recently, the media, always trying to make things sound sensational, have started to call totally eclipsed moon "the blood moon." Why does the Moon look reddish to us when there is a total lunar eclipse?

the earth's atmosphere bends different colors of light to a different degree. During a total lunar eclipse, the red light of the Sun, filtering through the Earth's atmosphere colors the moon red

according to the theory of plate tectonics...?

the liquid metal inside the Earth is developing plates of solid metallic material, which contributes to the Earth's magnetic field

the region around the Earth where charged particles are trapped and spiral around is called...?

the magnetosphere

the US has plans to build a 30-meter telescope, while the Europeans are thinking about 39-meter telescope. What technological innovation allows astronomers to be thinking about telescopes with that larger an aperture?

the mirror in these telescopes will be constructed from many small mirrors which will work together

the earth's escape speed is about 25,000 miles per hour. Escape speed depends on the gravity of the object trying to hold the spacecraft from escaping. Based on your understanding of gravity, how will the escape speed from the moon compare to the escape speed from Earth?

the moon's escape speed will be smaller than the Earth's

The celestial sphere turns once around each day because...?

the planet on which we live on is rotating

in Ptolemy's system the planets orbit the Earth and not the Sun. How did the system explain the retrograde motion of planets like Jupiter?

the planets move on a small circle whose center, in turn, circled a point near the Earth

after a long night of cramming for a test, your college roommate hits his head forcefully against the wall in despair. According to Newton's 3rd law, as he exerts a force against the wall, there must be an equal and opposite force. How does that opposite force show itself in this case?

the wall exerts a force on your roommates head and he has a headache

the major source of information about bodies in the universe is through...?

their light

what is the most important reason that astronomers have learned more about our planetary system in the last 30-40 years than all of history before then...?

we have been able to send spacecraft to gather information about planets and moons up close