A light year is a unit of
distance
Which of the following is the largest?
a. The Milky Way
b. The orbit of Pluto around the Sun
c. The Moon
d. The Earth
e. The Sun
The Milky Way
How long does it take the Earth to complete one orbit around the Sun?
one year
An observer looking towards Polaris is facing
north
The Sun Moon Planets and stars rise in the ___ and set in the ___
east/west
The ecliptic is inclined 23.5 degrees with respect to the celestial equator. This is a result of
the tilt of the Earth's rotational axis
The apparent path of the Sun across the celestial sphere during a year is called the
ecliptic
Light from the Sun takes approximately _____ to reach the Earth
8 minutes
The direction overhead of an observer defines his/her
zenith
In the local group, the two largest galaxies are called
The Milky Way and Andromeda
The ecliptic is
The path of the Sun on the celestial sphere
The projection of Earth's orbit onto the celestial sphere
Lunar eclipses do not occur every month because
The orbit of the Moon is tilted with respect to the ecliptic
When the phase of the Moon is full
The Moon and Sun are on opposite sides of the Earth
The various motions of Earth in increasing order of the period (duration) of the motion
Rotation, revolution, precession
The ancient Greek astronomer who first observed precession was
Hipparchus
No matter where you are on Earth, the stars appear to rotate about a point called the
celestial pole
We experience season because
The Earth's equator is tilted relative to the plane of the solar system
The Islamic calendar is based on
The orbit of the Moon around the Earth
At my house, days are 12 hours long, and nights are 12 hours long, every day of the year. I live at latitude
0 degrees
We always see the same side of the Moon because
The Moon rotates once every orbit around the Earth
We say a planet is showing retrograde motion when
It appears to move westward relative to the stars
An ancient Greek mathematician and astronomer who correctly deduced the relative Sun-Earth to Earth-Moon distances was
Aristarchus
The Gregorian calendar is
A solar calendar
Ptolemy is best known for
His epicyclic model of the solar system
Galileo was
The first person to record sunspots and discovered the moons of Jupiter
The asteroid belt is located
Between Mars and Jupiter
The Kuiper belt is located
farther from the Sun than Neptune
The terrestrial planets in our solar system are
Mercury, Venus, Earth, and Mars
Major differences between the terrestrial and Jovian planets
Terrestrial planets orbit closer to the Sun than the Jovian planets
Jovian planets have extensive atmospheres, whereas terrestrial planets do not
Terrestrial planets are higher in average density than Jovian planets
Jovian planets were formed outside the
Compared to the distance between Earth and Venus, the distance between Jupiter and Saturn is
much larger
A fact about Mercury's rotation
Mercury rotates 3 times for every 2 revolutions because of a resonance
Object with a surface most similar to the surface of Mercury
The Moon
The Caloris Basin on Mercury
Is an impact crater
One reason to prefer the Copernican model for the solar system over the Ptolemaic one is
Occam's Razor
Theory
In science, a broad idea or picture that has been repeatedly verified so as to give us great confidence that it represents reality
Why is the surface of Venus so hot
A runaway greenhouse effect, which results from Venus' thick atmosphere
Venus' rotation
Is slower than Earth's and retrograde
The Earth is said to be differentiated. This means that
It has layers with the densest material at its core
The planet whose rotational axis is nearly parallel to the ecliptic is
Uranus
When a spinning figure skater pulls in her arms to spin faster, her angular momentum
Remains the same
Constellations are
apparent patterns the stars make on the celestial sphere
The Earth ____ on its axis once every 24 hours
rotates
The Earth _____ around the Sun once every year
revolves
The orbit of the Earth around the Sun is an
Ellipse
___ and ___ are a coordinate system for defining points on the Earth
Longitude and Latitude
____ ____ and ______ are coordinates for points on the celestial sphere
right ascension and declination
At the poles, the stars rotate in ____ ____ to the horizon
circles parallel
At the equator, the stars rise in the east and set in the west at ___ degree angles with respect to the horizon
90
Stars that are always about the horizon - they rotate around the north and south celestial poles
circumpolar stars
Constellations along the ecliptic
The zodiac
The Earth precesses with a period of _________
26,000 years
The Sun's position in the sky at the same time every day over the course of the year is called
the analemma; it depends on latitude
Astronomer who has a successful geocentric model for the motion of the planets
Ptolemy
Proposed a heliocentric model for the motion of the planets, which had a simpler explanation for retrograde motion
Copernicus
Comets orbit the Sun in the...
Oort Cloud
Conservation of angular momentum means
the collapsing cloud rotates faster and faster
Venus has a very think atmosphere of
CO2
The greenhouse effect has heated the surface of Venus to
T=900F
The surface of Venus has been mapped by the ______, using radar
Magellan Spacecraft
_____ ______ of elements inside the Earth heat it and cause the lithosphere to be broken into tectonic plates
Radioactive Decay
The atmosphere of the Earth consists mostly of
N2 and O2
A cavity which protects the Earth from Solar Wind
Magnetosphere
The sky is blue on Earth because ______ _______ by the molecules in the atmosphere
Rayleigh scattering
The sky on the Moon appears black because
There is no atmosphere