AST Test 1

A star is 230 light years away. The light we see tonight from that star left it

230 years ago

What problem has precession caused for many of the schools of astrology?

Because of precession, the constellations are no longer lined up with the astrological signs that are named after them; since astrology was set up, the two have slipped one sign apart

When the authors of our textbook say that astronomers are like police detectives trying to solve crimes, they are explaining that:

Both astronomers and detectives must test their hypotheses against any evidence that they gather

The Renaissance astronomer who wrote the pioneering book that suggested the Earth probably orbits the Sun (instead of the other way around) was:

Copernicus

The first person who regularly turned a telescope to astronomical observations (and published his observations) was:

Galileo Galilei

Why is an absorption spectrum especially useful for astronomers?

It has dark lines in it that allow astronomers to determine what elements are in the star

The Earth is closest to the Sun in which month of the year?

January

The scientist who formulated the three laws of planetary motion by analyzing the data on the precise location of planets in the sky was:

Johannes Kepler

The first radio telescope was built in the 1930's by

Karl Jansky

The star that is currently closest to the North Celestial Pole is:

Polaris

The great astronomer of ancient times who summarized and improved a system of circles upon circles to explain the complicated motions of the planets (and published the system in a book now called The Almagest) is:

Ptolemy

Of these, which is the largest?

The Milky Way Galaxy

Of these which is the closest to us?

The Moon

A light year is

The distance that light travels in one year

What specific event really made it possible for the three laws of planetary motion to be discovered?

Tycho Brahe died and Kepler was able to get full access to his data

Newton showed that to change the direction in which an object is moving, one needs to apply:

a force

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

The time it takes for the Sun to return to the same place in our sky after the Earth has rotated once is called:

a solar day

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

a spectrometer

A large body in space that consistently makes its own light (instead of merely reflecting another body's light) is called

a star

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

Why is an image recorded with a CCD better for astronomers than an image recorded on photographic film or plates?

all of the choices are correct (CCD's allow more accurate measurements of the brightness of each part of the image CCD's have digital output that can go directly to a computer CCD's are more efficient; more of the light is recorded and not wasted)

We now know that the orbit of a stable planet around a star like the Sun is always in the shape of:

an ellipse

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

because the Earth is going around the Sun in the course of a year

Why do telescopes have to have a good motorized drive system to move them quickly and smoothly?

because the Earth is rotating, with the telescope attached to it

An idealized object that does not reflect or scatter any radiation that hits it, but simply absorbs every bit of radiation that falls on it is called:

blackbody

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

To come up with the precise mathematical form of his law of gravity, Newton first had to invent the mathematical techniques that we now call:

calculus

The most important function of an astronomical telescope is to:

collect as much light as possible and bring it to a focus

A new technique called adaptive optics allows astronomers to:

compensate for changes in the Earth's atmosphere and achieve better resolution

The 88 sectors into which astronomers today divide the celestial sphere (the whole sky) are called:

constellations

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

The way scientists know that a hypothesis in astronomy is a reasonable description of nature is to

do experiments and observations about the predictions of the hypothesis

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

full moon

Which of the following has the highest frequency?

gamma rays

You are on a camping trip, far away from city lights. You look up into the dark night sky, and see lots of stars, some brighter, some dimmer. All the stars you see with your unaided eye are

in the Milky Way Galaxy

The Julian calendar made the significant advance of:

introducing the leap year, so that every fourth year had an extra day

In the Northern Hemisphere, the altitude (height in degrees above the horizon) of the North Star is always roughly equal to the

latitude of the observer

When a planet, in its orbit, is closer to the Sun, it:

moves faster than average

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

new moon

A very wealthy donor decides to give a large sum of money to your college or university to build the world's largest visible-light gathering telescope. From an astronomical perspective, where would be the best location to put such a telescope?

on a tall, dry mountain peak

Which of the following has the longest wavelength?

radio waves

The earliest telescopes used by astronomers were:

refractors

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 declination

How fast do electromagnetic waves travel?

speed of light

The fastest speed in the universe is:

speed of light

A "New Age" bride and groom, who are enchanted by the Sun, want to get married on the day when it gets to be highest in the sky. If they live in the United States, around what day of the year will the wedding take place?

summer solstice

Wien's Law relates the wavelength at which a star gives off the greatest amount of energy to the star's

temperature

Why do astronauts (and cans of soft drink) float around in the Shuttle instead of falling?

the Shuttle is falling around the Earth (and everything aboard is in free fall)

Which of the following is an important part of the reason it is hotter in summer in North America than in winter?

the Sun's rays hit the Earth more directly in the Summer, and spread out less

Why does the Moon show phases in the course of a month?

the angle the Moon makes with the Sun changes and we see differing amounts of reflected sunlight

The Astronomical Unit (AU) as defined by astronomers is

the average distance between the Earth and the Sun

The Sun's apparent path around the celestial sphere is called

the ecliptic

For scientists, an element (like gold) is defined by

the number of protons in its nucleus

The celestial sphere turns once around each day because

the planet on which we live is rotating

The period of the moon's rotation on its axis is

the same as its revolution around the Earth

What would you have to change about the Earth to stop our planet from having significantly different seasons?

the tilt of its axis

The strip of the sky through which the Sun, the Moon, and the bright planets appear to move in the course of a year is called:

the zodiac

(In the absence of a strong magnetic field), what is the chief factor that determines what type of electromagnetic radiation objects give off:

their temperature

The light which allows you to see this very interesting exam is made up of waves. In these waves, the distance between crests is called the:

wavelength

Astronomers discover a new comet that orbits the Sun, but has its aphelion (the furthest point in its orbit) beyond Neptune. Astronomers studying this comet have the right to expect that it:

will follow Newton's laws of motion

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