astronomy test 1
Human eyes evolved to detect visible light because
...
An astronomy textbook 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. If it is now twice as far from the center of the Earth than when you were reading it, what would it weigh? (Note, assume that the book is moving away from the Earth not falling freely around it.)
1 pound
From horizon to opposite horizon, the sky takes up how much angular distance?
180 degree
The period of the moon's rotation on its axis is
28 days
The largest visible-light telescopes in the world use what device to collect as much light as possible before the light is brought to a focus (to act as the light bucket)?
A mirror
A Hertz is
A unit of frequency
Which ancient Greek thinker suggested (long before Copernicus) that the Earth is moving around the Sun?
Aristarchus
The scientist who first devised experimental tests to demonstrate the validity of the heliocentric model of the solar system was
Copernicus
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 time it takes for the Sun to return to the same place in our sky after the Earth has rotated once is called:
Half-life
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 planet with the shortest period of revolution is
Mercury
The idea that atoms radiate energy only when their electrons move from higher to lower energy levels was first advanced by:
Niels Bohr
To get away from the pressures of your astronomy class you and some friends decide to go to a football game. In the stadium, a friend gives you her binoculars to look through, and suddenly you realize that you are back to a subject covered in astronomy class. What type of telescope are you looking through when you use binoculars?
Refractor
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
Halfway between the celestial poles lies the
The celestial equator
The 17th century astronomer who kept a roughly 20 year continuous record of the positions of the Sun, Moon, and planets was
Tycho Brahe
The most important function of an astronomical telescope is to
a. collect as much light as possible and bring it to a focus
Most ultraviolet radiation does not penetrate to the Earth's surface. Instead it is absorbed in:............
absorbed by oxygen in the ozone layer
Which of the following electromagnetic waves travels through space the fastest?
all at the same speed
Two stars are giving off electromagnetic radiation. The hotter star will
all of the above
The size of the device that gathers (collects) radiation is called a telescope's
aperture
As seen from the continental United States, the Big and Little Dipper
are in the north circumpolar zone throughout the year
A new technique called adaptive optics allows astronomers to
b. compensate for changes in the Earth's atmosphere and achieve better resolution
Why do telescopes have to have a good motorized drive system to move them quickly and smoothly?
because earth is rotating
If the Earth goes around the Sun, why is the ecliptic not lined up with the celestial equator?
because of the inclination of the earth's axis by 23.5 degrees
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 different types of atoms (elements) give off or absorb different spectral lines?
because the spacing of the energy levels is different in different atoms
The asteroid belt is
between Mars and Jupiter
The minimum speed required to launch an object so that it remains the same distance above the ground and just falls around the Earth is called
circular satellite velocity
The 88 sectors into which astronomers today divide the celestial sphere (the whole sky) are called:...
constellations
After a nice dinner around the campfire on a camping trip, you and a friend decide to get away from the fire to observe the stars. As you get farther and farther away, you see the brightness of the fire:
decrease in proportion to the square of its distance from you
Which of the following consists of electro-magnetic waves with the shortest wavelength?
dental x-ray
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
When England and the American colonies finally adopted the Gregorian calendar in 1752, what dramatic change had to be made?
drop 11 days out of september and make january 1st the first day of the year
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
ecliptic
In the 19th century, it became clear that magnetism was not a separate force, but was always produced by the action of
electric charges that were in motion
We now know that the orbit of a stable planet around a star like the Sun is always in the shape of
ellipse
To leave the gravitational pull of the Earth, and explore other planets, satellites must have at least
escape velocity
According to Kepler's 2nd Law, comets (which have eccentric orbits) should spend a lot more of their time
far from the sun
Newton showed that to change the direction in which an object is moving, one needs to apply
force
During what phase of the Moon is the Moon up only during the night hours and all night long?
full
What phase of the Moon must it be to have a lunar eclipse?
full
The first person (to the best of our knowledge) regularly to turn a telescope to astronomical observations was
galileo galilei
Which of the following electromagnetic waves has the highest frequency?
gamma rays
The "prime meridian" (where longitude equals zero) passes through:
greenwich,england
One of the great triumphs of spectroscopy was when astronomers identified a new element in the Sun (one that was only later found on Earth). Today, this element is called
helium
Typically, astronomers express the right ascension of a star on the sky in what units?
hours,mins,secs
Atoms typically consist of electrons, protons, and neutrons. The most common isotope of one element, however, only has two of these three types of particles. This element is
hydrogen
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
Two versions of an element with different numbers of neutrons are called
isotopes
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
A friend of yours who takes her astronomy class very seriously challenges you to a contest to find the thinnest crescent moon you can find just after new moon. What time of day is best for looking for this very thin crescent?
just as the sun is setting, or just after
In Australia (in the Southern Hemisphere) when are the days the shortest and the nights the longest?
late june
The number of degrees of arc that your location is north or south of the Earth's equator is called your
latitude
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
The fastest speed in the universe is
light
In locating objects on the celestial sphere, we call the number of degrees east or west 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
What happens as an electron falls from a higher level to a lower level in an atom?
loses a photon
Which of the following is NOT done best with a spectrometer?
measuring how bright sources of light in the universe appear
How did Eratosthenes measure the size of the Earth?
measuring system called stades
Which of the following is not a type of radio wave?
microwave
Astronomers observe a typical star using a telescope and a spectrometer. They will see
more than one of the above
When white light passes from the air into a different medium such as glass, it
more than one of the above
What phase of the Moon must it be to have a solar eclipse?
new
At which of the following locations on Earth is the direction we call East not clearly defined?
north and south poles
The south celestial pole and the north celestial pole lie in the sky directly above the
north and south poles
Where on Earth do stars always circle the zenith (and never rise and set)?
north pole
When a comet like Comet Hale-Bopp comes closest to the Sun in its orbit, we say that it is at
perihelion
The star that is currently closest to the North Celestial Pole is
polaris, or the north star
The slow tipping of the Earth's axis in a circle with a period of about 26,000 years is called
precession
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
pythagoras
Which of the following electromagnetic waves has the longest wavelength?
radio waves
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
A fashion designer decides to bring out a new line of clothing which reflects the longest wavelength of visible light. These articles of clothing will be what color to the human eye?
red
The earliest type of telescopes used by astronomers were
refractors
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
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
A dashing Romanian count asks his sweetheart to marry him. She says she will give her reply when the Moon is full. If he asked when the Moon was at first quarter, how long will he have to wait?
seven days
What time of day (roughly) will a new moon rise?
sunrise
(In the absence of a strong magnetic field), what is the chief factor that determines what type of electromagnetic radiation objects give off
temperature
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 celestial sphere turns once around each day because
the celestial sphere does not move, is the earth that turns around once each day
Why do satellites launched into low-Earth orbits not remain there indefinitely?
the drag generated by friction with the thin upper atmosphere eventually leads to a loss of energy and "decay" of the orbit.
In an ellipse, the ratio of the distance between the foci and the length of the major axis is called
the eccentricity
The Sun's apparent path around the celestial sphere is called
the ecliptic
The Julian calendar made the significant advance of
the leap year
Every celestial object appears to go around the Earth once a day. In addition to this motion, which celestial object has the fastest apparent motion in the sky?
the moon
Which of the following statements about the nucleus of a typical atom (such as the carbon in your little finger) is FALSE
the nucleus repels the electrons which move around it
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 moved on a small circle whose center in turn circled a point near the Earth
Which of the following statements about the force of gravity is FALSE?
the strength is the inversely proportional to the mass. the more mass equals less gravity
What would you have to change about the Earth to stop our planet from having significantly different seasons
the tilt of its axis
How did the world's countries solve the problem that mean solar time varies continuously as a traveler's longitude changes?
the world was divided into 24 time zones
Why was the problem of devising a workable yearly calendar so difficult on Earth?
variables like change in the earth's motion and the drift of equinoxes created difficulties
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
The point in the sky directly above your head at any given time is called the
zenith
