Exam 1

What is one important way in which both the Moon and Mercury are different from Earth?

they do not have an atmosphere

All molecules (like molecules of water or carbon dioxide) are made up of

two or more atoms

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

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

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

zenith

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

From horizon to opposite horizon, the sky takes up how much angular distance?

180 degrees

Light travels 3 x 105meters every second. That number in words is 30 meters

300,000 meters

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

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 scientist who first devised experimental tests to demonstrate the validity of the heliocentric model of the solar system was

Galileo

In what fundamental way did the work of Galileo differ from his predecessors who had thought about the sky?

Galileo used instruments and experiments to show him what nature was doing, instead of relying on pure logic

Which of the following are reasons why many people consider Isaac Newton one of the greatest scientists who ever lived? Mark all that are correct.

He formulated the laws that govern all motion in the universe He figured out the mathematical form of a law of universal gravity He combined the work of Galileo, Brahe, and Kepler into one framework

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 scientist who worked out the mathematics of the connections between electricity, magnetism, and light in the 19th century was:

James Clerk Maxwell

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

A planet in our solar system whose composition resembles that of our Sun is:

Jupiter

When NASA and a group of astronomers sent up a spacecraft designed to find planets orbiting other stars, they named it after Kepler. Why was this an appropriate name?

Kepler figured out the rules of planetary motion, which planets in our solar system and planets elsewhere must obey

The planet closest to the Sun in the solar system is:

Mercury

The planet in our solar system with the shortest period of revolution is

Mercury

The planet in our solar system whose orbit actually brings it inside the orbit of another planet is

Pluto

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

Polaris

Some college students decide to form a secret society that would meet each year after graduation at a time when the day and night were the same length. Which of the following would be a time they could meet?

September 23

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

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

Which of the following is the Earth NOT located in?

You can't fool me, we are located in all of these

When a projectile (a rock from space, say) hits the surface of the Moon, which of the following do we NOT get?

a gushing out of lots of water that had been frozen inside the ground on the cold Moon, but is briefly heated by the impact

The location of the Earth in the Milky Way Galaxy is _____.

a little less than 30,000 LY from the center

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

a star

From a particular location on Earth, why can we see many more total eclipses of the Moon than total eclipses of the Sun?

a total lunar eclipse is visible over a much larger part of the Earth's surface than a total solar eclipse

The asteroid belt is

a zone where rocky chunks orbit between Mars and Jupiter

If the moon is at first quarter right now, how long do you have to wait to see the full moon?

about a week

The smallest piece of an element (like gold or lead) that still has all the properties of that element is called

an atom

The laws of nature (as determined by scientists) can be described many ways. Mark all that are correct.

are constructed from many observations, hypotheses, and experiments apply both on Earth and among the stars are often written in the language of mathematics

The laws of nature (as determined by scientists) can be described many ways.

are constructed from many observations, hypotheses, and experiments, apply both on Earth and among the stars, are often written in the language of mathematics

When chemists say that a planet's upper regions are reduced,they mean that these regions

are dominated by the element hydrogen and its compounds

From a city in the U.S., where in the sky would you look to see a star that is not turning with the motion of the sky in the course of a night?

at the north celestial pole

Why are the largest craters we find on the Moon and Mercury so much larger than the largest craters we find on the Earth?

because the largest craters were made early in each world's history, and geologic activity has erased all traces of this early period on the Earth's surface

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

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 88 sectors into which astronomers today divide the celestial sphere (the whole sky) 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

Which of the following is NOT something that was accomplished by the Apollo missions to the Moon?

discovering that the Moon has a great deal of water under its surface

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.

Even with the best and largest telescopes, we can't see all the stars in the Milky Way Galaxy, even though these same telescopes can show us other galaxies. This is because

dust in the space between stars builds up over large distances and blocks the light of stars behind the dustier parts of the Milky Way

Which of the following statements about forces are TRUE? Mark all that apply.

forces change the momentum of a body where there is no force, objects continue to move the way they were moving forces cause an acceleration to take place forces always occur in equal and opposite pairs

In radioactive dating, the measure scientists use to note how long (on average) a particular radioactive nucleus will take to decay is called its:

half-life

When it comes to our place in the solar system today, which model do we accept?

heliocentric

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 idea that objects (in the absence of an outside force) tend to continue doing what they are already doing is called the law of

inertia

When white light passes from the air into a different medium such as glass, it:

is refracted (bent)

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

Sometimes, when the Moon is a thin crescent, you can still dimly make out the full disk of our satellite. What is the reason for this?

light reflecting from the Earth onto the Moon

In locating objects on the celestial sphere, we call the number of degrees east or west that something is from Greenwich, England its

longitude

How do astronomers learn what elements are present in a given star?

look at the absorption lines in its spectrum

The large, roughly circular, dark, and somewhat younger regions on the Moon are called:

maria

Astronomers observe a typical star using a telescope and a spectrometer. They will see:

more than one of the above

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

new

Which of the following statements about our Moon is FALSE?

on Earth, we can see all its sides in the course of a month as it goes around us

The slow tipping of the Earth's axis in a circle with a period of about 26,000 years is called

precession

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 wavelength that carry FM broadcasts

When a planet temporarily moves westward in the sky over the course of several weeks or months (instead of eastward, as it typically does), we call it

retrograde motion

The lunar highlands are made mostly of rocks that

rose to the top as the Moon cooled from a molten state early in its history

If there really were a Santa Claus at the North Pole, what would the cycle of the seasons be like for him and Mrs. Claus?

six months of light, followed by six months of darkness (or at least dark twilight)

When the Sun and Moon are lined up and pull together, the tides they raise are called:

spring tides

If the Earth goes around the Sun, why is the ecliptic not lined up with the celestial equator?

the Earth's axis is tilted by about 23 degrees from the vertical

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)

Mercury is a small planet and therefore has trouble holding on to an atmosphere. How then do scientist account for the extremely thin atmosphere that was found around the planet in 1985?

the Sun's "wind" of particles is chipping atoms off the surface of Mercury

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

The Astronomical Unit (AU) as defined by astronomers is

the average distance between the Earth and the Sun

A light year is ______.

the distance that light travels in one year

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

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

the ecliptic

What formation or formations are evidence that the planet Mercury may have shrunk (gotten a bit smaller) as it cooled?

the long scarps or cliffs

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

the number of protons in its nucleus

Most ultraviolet radiation does not penetrate to the Earth's surface. Instead it is absorbed in:

the ozone layer

In Ptolemy's system the planets orbit the Earth rather than the Sun. How did this system explain the retrograde motion of planets like Jupiter?

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