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140 Cards in this Set

  • Front
  • Back

You note that a particular star is directly overhead. It will be directly overhead again in

23 hours 56 minutes.

In general, what is true of the alpha star in a constellation?

It is the brightest star in the constellation.

What celestial line is a product of the Earth's orbit around the Sun?


Modern scientific theories are NOT:


If new Moon fell on March 2nd, what is the Moon's phase on March 14th?

waxing gibbous

Into how many constellations is the celestial sphere divided?


Some type of solar eclipse will happen about:

about every six months at new moon.

Where would you be if the Sun sets for six continuous months, beginning on September 23rd?

North Pole

Which statement about the length of a day is FALSE?

The sidereal day includes both the Earth's rotation and revolution around the Sun

Which of the choices below correctly lists things in order from largest to smallest?

Universe, Local Group, Milky Way, Solar System

Which statement about the first quarter moon is FALSE?

From the Earth, it appears 25% sunlit.

The places where the Sun crosses the equator are called the:


From a location in the United States of America, a star is observed to be rising due East. Where will this star be located 6 hours later?

High in the southern sky.

A lunar eclipse can only happen during a:

full moon.

When the sun rises it is located in the constellation Gemini. When the sun sets later that same day it will be

in the constellation Gemini.

Which statement about the ecliptic is FALSE?

The Moon can never leave it, but moves twelve times faster than the Sun.

What conditions are necessary for a partial solar eclipse?

new moon on ecliptic, with us in the penumbral shadow

Which of the following describes parallax?

It is inversely proportional to the distance to the star.

About how many stars are visible on a clear, dark night with the naked eye alone?

a few thousand

When the Moon is directly opposite the Sun in the sky, its phase is


The Law of Universal Gravitation was developed by:


A fatal flaw with Ptolemy's model is its inability to predict the observed phases of

Mercury and Venus

According to Kepler's third law, the square of the planet's period in years is:

proportional to the cube of its semimajor axis in AU

Given that the planet orbiting the nearby star 51 Pegasi is about 20X larger than the Earth, but 400X more massive, on that world you would weigh:

the same as you do here

The heliocentric model was actually first proposed by:


Which of the following was NOT a contribution of Galileo to astronomy?

The changing appearance of Saturn's rings corresponds to our seasons.

Tycho Brahe's contribution to Kepler's Laws of Planetary Motion were

his detailed and accurate observations of the planet's position.

Kepler's first law worked, where Copernicus' original heliocentric model failed, because Kepler described the orbits as

elliptical, not circular

Which of these observations of Galileo refuted Ptolemy's epicycles?

the complete cycle of Venus' phases

The place in a planet's orbit that is closest to the Sun is called


The greatest contribution of the Greeks to modern thought was:

the development of scientific inquiry and model building.

How much stronger is the gravitational pull of the Sun on Earth, at 1 AU, than it is on Saturn at 10 AU?


Which of the statements below is part of both the Ptolemaic and Copernican models?

The Moon orbits the Earth once a month

Galileo found the rotation period of the Sun was approximately

a month

The Ptolemaic model of the universe:

explained and predicted the motions of the planets with deferents and epicycles

Scientists today do not accept the Ptolemaic model because:

the work of Tycho and Kepler showed the heliocentric model was more accurate.

A circular orbit would have an eccentricity of


Which of these was NOT a telescopic discovery of Galileo?

the moons of Saturn

Geosynchronous satellites orbit at about four earth radii, where the earth's gravitational pull is:


Upon which point do Copernicus and Kepler disagree?

The orbits of the planets are ellipses, with one focus at the Sun.

What does the phenomenon of interference demonstrate?

the wave nature of light

Electromagnetic radiation

can behave both as a wave and as a particle.

Which type of radiation can be observed well from Earth's surface?


Star A and star B have the same temperature, but star A is 5 times bigger than star B. Which statement below is correct?

Star A and star B have the same color, but star A is brighter.

The two forms of electromagnetic radiation that penetrate the atmosphere best are:

visible and radio waves.

There are no X-ray telescopes on Earth because

X-rays don't penetrate Earth's atmosphere

Hot objects with temperatures of 10 million Kelvin give off most of their radiation in which part of the electromagnetic spectrum?


The total energy radiated by a blackbody depends on

the fourth power of its temperature.

Increasing the temperature of a blackbody by a factor of 3 will increase its energy by a factor of


If a light source is approaching you at a speed very close to the speed of light, it will appear

bluer than it is

Which statement gives the relationship between the waves in the electric and magnetic fields in an electromagnetic wave?

They are in phase but perpendicular to each other in space.

Star A has a temperature 1/2 that of star B, but star A is 5 times bigger than star B. Which statement below is correct?

Star A is redder and brighter than star B.

If a wave's frequency doubles, its wavelength

is halved

The Earth's ionosphere partially blocks which form of electromagnetic radiation?


Star A and star B have the same temperature, but different luminosities. What can you infer about these two stars?

Nothing can be inferred from the information given.

Colors appear different to us because of their photons' different:


To see the Sun's hot corona (a temperature of 1,000,000 K, which part of the electromagnetic spectrum should one observe?

the x-ray

The light from an object moving tangentially (to your left or right) will exhibit

no shift

There are no radio telescopes in space because

radio waves penetrate Earth's atmosphere so there is no need to put one in space

What is true of a blackbody?

Its energy peaks at the wavelength determined by its temperature.

Which of these is the classic continuous spectrum?

a rainbow

A hydrogen atom consists of an electron and a(n)


The Orion Nebula, M-42, is a hot, thin cloud of glowing gas, so its spectrum is:

a few bright lines against a dark background.

An incandescent light (glowing tungsten filament) produces:

a continuous spectrum, with the peak giving the temperature of the filament.

If a source of light is approaching us at 3,000 km/sec, then all its waves are

blue shifted by 1%

The particles which enter into chemical reactions are the atom's:


For hydrogen, the transition from the second to the fourth energy level produces

a blue green absorption line.

Typical stellar spectra appear as:

a rainbow, but with some dark lines mixed in.

The Fraunhofer lines in the solar spectrum are actually:

absorption lines due to the thin outer layer above the photosphere.

The particle which adds mass but no charge to the atomic nucleus is the:


If the rest wavelength of a certain line is 600 nm., but we observe it at 594 nm, then

the source is approaching us at 1 % of the speed of light.

The energy required to move an electron in a hydrogen atom from energy level 2 to energy level 3 is

1.9 eV

In Bohr's model of the atom, electrons

only make transitions between orbitals of specific energies

Which of the following type of electromagnetic radiation has the lowest energy?


The classical model of the hydrogen atom that explains its spectral line structure is due to:


In the atom, which particles gives the element its identify (atomic number)?


Which of the following type of electromagnetic radiation has the highest energy?


An emission spectrum can be used to identify a(n)


The three laws dealing with the creation of various spectra are due to:


The observed spectral lines of a star are all shifted towards the red end of the spectrum. Which statement is true?

This is an example of the Doppler effect

What problem do refractor telescopes have that reflectors don't?

chromatic aberration

Compared to optical telescopes, radio telescopes are built large because

radio photons don't carry much energy.

Which of the following greatly improves the angular resolution of radio maps?

use of interferometers

It is diffraction that limits the ________ of a telescope of a given objective diameter.


Which of these devices helps correct coma in fast reflectors?

Schmidt corrector plate

Which of the following is currently supplying high resolution X-ray images from space?


In astronomy, an interferometer can be used to

improve the angular resolution of radio telescopes

Which design has a convex primary mirror and flat secondary mirror, with the eyepiece located on the top side of the telescope tube?

Newtonian reflector

Radio dishes are large in order to:

increase their angular resolution and collect the very weak radio photons.

This design combines the radiation from two different telescopes to greatly enhance resolution via computer synthesis.


What is "seeing"?

a measurement of the image quality due to air stability

Refractor telescopes suffer from this separation of light into its component colors.

chromatic aberration

A telescope with a 60 mm objective lens collects how many times as much light as does your eye's 6 mm exit pupil?


One advantage of the Hubble Space telescope over ground based ones is that

in orbit, it can operate close to its diffraction limit at visible wavelengths.

What is the resolving power of the telescope?

the ability to distinguish adjacent objects in the sky

Which type of telescope has the simplest light path?

prime focus reflector

What are two advantages of large scopes over smaller ones?

Large telescope have more light grasp and better resolution.

Which method of astronomical measurement is the precise measurement of brightness?


Green light has a shorter wavelength than orange light. In a 5 inch telescope, green light will

provide better angular resolution than orange light.

It is diffraction that limits the ________ of a telescope's objective.


What is the absolute magnitude of our Sun?


On the H-R diagram, red supergiants like Betelguese lie

at the top right.

In general, the narrower the spectral line of a star:

the bigger the star is.

The Hertzsprung-Russell Diagram plots ________ against the spectral type or temperature.

luminosity or absolute magnitude

What is proper motion?

It is the annual apparent motion of a star across the sky.

Upon what data do measurements of sizes of eclipsing binaries depend?

their Doppler shifts and durations of stages of their eclipses

If a star has a parallax of 0.05", then its distance in light years is about:

65 light years

For a star of 10 solar masses, its main sequence life span will be:

only 1/1000th of the Sun.

Star A and star B both have an apparent magnitude of 7.0, but star A is at a distance of 15 pc and star B is at a distance of 30 pc. Which statement below is correct?

Star A and star B appear to have the same brightness, but actually star B is brighter than star A.

Which of the following is the most common type of star?

low mass main sequence

Star A and star B both have an apparent magnitude of 4.0, but star A has an absolute magnitude of 1.0 and star B has an absolute magnitude of 7.0. Which statement below is correct?

Star A and star B appear to have the same brightness, but actually star A is brighter than star B.

At the distance of Jupiter (6 times further away from the Sun than Earth) the amount of sunlight received per square centimeter different by what factor?

36 times less

Which type of binary can have their sizes measured directly by photometry?


If a star appears to move back and forth relative to other stars over a six-month period, this motion is due to the star's

parallax shift

Stars that have masses similar to the Sun's, and sizes similar to the Earth are

white dwarfs

In a visual binary system with circular orbits, if in 20 years the two stars' position angles have shifted by 30 degrees, the pair's period must be:

240 years.

About how many stars has Hipparcos given us accurate distance data on?

a million, those with parallaxes of .005" or larger

Star A and star B both have an absolute magnitude of 2.0, but star A has an apparent magnitude of 5.0 and star B has an apparent magnitude of 7.0. Which statement below is correct?

Star A appears brighter than star B, but actually star B and star A are the same brightness.

What are the two most important intrinsic properties used to classify stars?

luminosity and surface temperature

On the H-R diagram, the Sun lies

about the middle of the main sequence.

What do "forbidden" lines reveal about interstellar space?

The density or pressure of this gas is much lower than can be produced in a laboratory.

The ________ of light passing through thin dust clouds lets us map the Galaxy's magnetic field.


in the Milky Way galaxy, gas and dust are found


What effect does even thin clouds of dust have on light passing through them?

It dims and reddens the light of all more distant stars.

The most common molecule in a molecular cloud is:

molecular hydrogen, H2.

What feature of interstellar dust is inferred by the polarization of starlight?

its shape

Which of the following have not yet been observed in space?


What color is a H I region?

colorless; it emits in the radio region

The relative density of dust to gas is least in which place?

the atmosphere of Earth

Charles Messier mapped the night sky and identified many objects now known to be emission nebulae in his search for objects that might be confused with


A large gas cloud in the interstellar medium that contains several type O and B stars would appear to us as

an emission nebula.

Due to absorption of shorter wavelengths by interstellar dust clouds, distant stars appear


The overall dimming of starlight by interstellar matter is called


Which statement about the dark nebulae is true?

They can be penetrated only with longer wavelengths such as radio and infrared.

Why is 21-cm radiation so important to the study of interstellar matter and the Galaxy?

Emitted by hydrogen, it passes through interstellar dust and lets us to map the entire Galaxy.

A reflection nebula is caused by

starlight scattered by dust particles.

Interstellar dust clouds are best observed at what wavelength?

Radio and infrared

Which is the least dense?

interstellar dust

The average temperature of the typical dark dust cloud is about


Emission nebulae like M42 occur only near stars that emit large amounts of

ultraviolet radiation.