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What was the material from which the solar system formed?

A nebula made mostly of hydrogen and helium gas, but enriched in heavier elements from supernova explosions

Fusion is the process by which

elements are transformed into heavier elements by nuclear reactions

The radial velocity of a star or other object is measured by

observing the Doppler shift of spectral lines in the light from the object.

The most abundant material in the universe is


Accretion is the process by which

dust grains and ice crystals coalesce to form planetesimals.

What is a proplyd?

A protoplanetary disk, such as those observed around some stars in the Orion nebula

The time-scale over which material in the solar nebula accreted to form planets was about

100 million years.

The asteroid belt exists between the orbits of which planets?

Mars and Jupiter

Which planets have one or more satellites (or moons) orbiting them?

All except the inner two planets

The troposphere of the Earth is

the atmospheric layer closest to the ground.

What percentage of the sunlight that falls on the Earth is reflected back into space?


The atmosphere that we are now breathing is

the third atmosphere that the Earth has had

In which layer of the Earth's atmosphere is the ozone layer located?

The stratosphere

Earth has an average density that is approximately

five times that of water.

The type of rock that makes up the lunar highlands is


Mercury's average density and the fact that it has a (weak) magnetic field lead to the conclusion that its central core is probably
composed of

solid and/or molten iron.

Caloris Basin

large impact crater on mercury

What name is given to the concentration of mass that formed at the center of the solar nebula and eventually became the Sun?


Which is the most abundant gas in Earth's atmosphere?


In which of the following ways is there a similarity between Jupiter and the Earth?

Auroras are produced by magnetospheres on both planets.

Where are the Earth's Van Allen radiation belts located?

In the magnetosphere

Jupiter has a magnetic field that is

much more powerful than that of the Earth.

The Cassini division is

a major division in the rings of Saturn, seen from Earth.

gives Uranus its blue-green coloration

Absorption of red light by methane

planet has its rotation axis tilted at 98°


Asteroids that orbit the Sun in the stable Lagrange points in Jupiter's orbit are known as


temperature of the visible surface of the Sun is

5800 K

50,000 is written in powers-of-ten notation as


bright stars Vega, Deneb, and Altair form

the summer triangle

modern astronomy, the constellations are

88 non-overlapping sky regions, covering the whole

From a location in the northern hemisphere, the pole star always appears at an angle above the northern horizon equal to

the latitude of the location.

Moon's angular diameter in our sky is measured to be 0.5°.

the diameter of the Moon in kilometers if we know the Moon's distance.


the path traced out by the Sun in our sky over one year against the background stars.


a slow motion of Earth's axis that traces out a cone over a period of 26,000 years

inclination of the Moon's orbit to the ecliptic plane?

5 degrees

tilt angle of the Earth's spin axis to the direction perpendicular to the ecliptic (known as the ecliptic pole)

is 23.5° and fixed

light-year is a measure of


constellation whose stars are used as pointers to the north celestial pole in the northern hemisphere at this time in
history is

Ursa Major, the Big Dipper

nearest star beyond our Sun is

Alpha -Centauris

celestial sphere is divided into this many constellation regions


Crab nebula is found in this constellation


human being (height about 2 m) larger than the nucleus of a hydrogen atom, or proton (diameter about 10-15 m)?


About how many stars could a galaxy contain?


brightest star


Centimeters = Meter


1 arcsecond

1/3, 600 degrees

During the middle of March, the Sun appears to move through


Sun dials is made possible by the equation of time also known as

the analemma

As the Moon orbits the Earth, we say the Moon moves


phase of the Moon at the time of solar eclipse

new moon

Polaris is the name for the bright star almost directly in line with the north polar axis of Earth. What is the name of the
bright star almost directly in line with the south polar axis of Earth?

There is no bright star almost directly in line with Earth's south polar axis.

From any location on Earth, the zenith defines a direction

vertically above an observer.

How many constellations does the zodiac contain


The plane of the ecliptic intersects the celestial equator

at two points, the vernal and autumnal equinoxes

average speed does the Sun appear to move across our sky

1 degree per day

The equinoxes are located at the intersections of the

ecliptic and the celestial equator

One synodic month is longer than one sidereal month by about

1 hour

inclination of the Moon's orbit to the ecliptic plane?

5 degrees

annular eclipse

An eclipse of the Sun in which the Moon is too distant to cover the Sun completely, so that a ring of sunlight is seen around the Moon at mid-eclipse.

1 nanometer (nm) is

10^-9 m

showed that light does not travel at infinite speed?

Ole Rømer in 1675

What is the linear momentum, p, of an object

The product of an object's mass times its velocity, p = mv

WESTWARD motion of a planet from night to night compared to the background stars

retrograde motion

Which one of the following is not part of the scientific method?

determine consistence with recognized authorities

Ptolemy's was


The best time(s) to see inferior planets from the Earth

greatest elongation

person who compiled the large set of accurate observations of planetary positions

Tycho Brahe

Kepler as a young man became the assistant to

Tycho Brahe

developed the first reflecting astronomical telescope


light spectrum would contain the highest energy photon

ultra violet

predicted the existence of the planet Neptune

Addams Levier

radiation has the longest wavelength

radio waves

wavelength regions MUST be observed from space because almost no energy in this region reaches the ground


If two photons in a vacuum have different energies, what can we say about the wavelengths of these photons

The high erenergy photon has the shorter wavelength.

first reflecting astronomical telescope


first radio energy to be detected by man from outer space came from

center of the milky way

detector that in many instances has replaced the photographic plate for astronomical photography


best shape for the cross-section of a simple astronomical mirror in order to produce the sharpest images of very distant objects
at its prime focus is

parabolic shape

Pieces of metal are heated by varying amounts in a flame. The hottest of these will be the one that shows which color most prominently?


We plot the intensity of the radiation emitted from an object at a certain temperature versus its wavelength. As we increase the
temperature, the wavelength at which the spectrum peaks becomes shorter and shorter. This is an example of

Wein's Law

melting point of water ice is

273 K

The Sun's spectrum peaks in the yellow-green region of the spectrum

the hotter the whiter

ionized hydrogen atom


The Balmer series of visible spectral emissions from hydrogen gas arises from transitions in which electrons jump between energy

from higher levels to the first excited level, n = 2

If you want to design a device that will detect animals at night by the radiation they give off, even if the night is totally dark, to
what wavelength range should you make the device sensitive?


the temperature of freezing water

273 K

Spectral lines are of particular importance in astronomy because

each different element has a characteristic line spectrum

force that holds the atomic nucleus together

strong nuclear

idea that light consists of photons, bundles of pure energy, was first proposed by


Light that originates in hydrogen atoms in which electrons have jumped from high levels to the level n = 2 will be part of which
series of spectral lines?


What is a filament on the Sun?

A prominence seen in
silhouette against the photosphere

What is the Zeeman effect?

The attraction of two areas of opposite magnetic polarity toward each other

A particular star has an angle of parallax of 0.2 arcsecond. What is the distance to this star?

5 pc

How many times brighter than a magnitude +4.0 star is a magnitude +3.0 star

2.512 times brighter

A star in the lower left part of the Hertzsprung-Russell diagram, compared to a star in the middle of the diagram, is


Which two physical parameters of stars are plotted on the Hertzsprung-Russell diagram to show the systematics of a group of
stars (e.g., a cluster)?

Lum and surface temp

The stars that last longest are

those with the smallest mass

New stars are formed from

huge, cool dust and gas clouds.


iron atoms that have lost 13 electrons

temperature of the solar corona

1-2 mill K

temperature at the center of the Sun

1.5X10^7 K

Parallax of a nearby star is used to estimate its

distance from Earth.

total time the Sun will spend as a main-sequence

10 billion years

Which stars undergo a helium flash in their cores

stars of less than 2 solar masses

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