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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