AST1002 Chapter 2
Which of the following terms describes the event in which the Moon is directly centered over the disk of the Sun from the vantage point of Earth but is relatively far away from Earth in its orbit, so it is not large enough in our sky to cover the entire Sun?
an annual solar eclipse
In reality, the Celestial Sphere is
an imaginary surface on which distant objects appear to lie, which rotates because Earth is spinning on its axis.
No matter where you are on Earth, stars appear to rotate about a point called the:
celestial pole
The apparent path of the Sun across the celestial sphere during a year is called the:
ecliptic plane
The amount of the Earth's surface receiving sunlight during the day is
less in the northern hemisphere than in the southern hemisphere during December.
When the Moon is in a quarter phase, the
line connecting the Sun and Earth is at a right angle (90°) to the line connecting the Earth and the Moon.
If Earth's axis were tilted twice as much as it currently is, we would experience
more extreme seasons
A partial solar eclipse occurs when
only part of the Sun's disk is covered by the Moon from the vantage point of an observer on Earth.
A lunar eclipse is possible
only when a full Moon's orbit intersects Earth's orbital plane around the Sun.
A solar eclipse is possible
only when a new Moon's orbit intersects Earth's orbital plane around the Sun.
From the equator, stars at night will seem to
rise in the east, move overhead, and then set in the west.
A sky observer in the Southern Hemisphere would
see stars moving clockwise around the south celestial pole.
If you are located at a position of latitude 30° north, a star that you observe near the north celestial pole will
stay up longer than a star located on the celestial equator.
If the north celestial pole is located at your zenith, what is your latitude?
+90°
Residents of the Southern Hemisphere cannot see the stars around the north celestial pole because
Earth itself is in the way
In six months, you will be able to see a different set of stars in the night sky because
Earth will move
We experience seasons because:
Earth's equator is tilted relative to the plane of the Earth's orbit around the Sun.
From the perspective of a viewer in the Northern Hemisphere, which of the following is always true?
The north celestial pole is always somewhere overhead
What causes the Moon to go through phases?
The relative positions of the Moon, Sun, and Earth as the Moon orbits Earth.
The average distance from Earth to the Sun is roughly 150 million kilometers. Assuming Earth's orbit around the Sun is circular, what is its orbital speed? Note that it takes about 365 days for Earth to complete one orbit.
108,000 km/hr
Earth's rotational axis precesses in space and completes one revolution every:
26,000 years
The speed of sound is 340 meters per second. About how long does it take sound to travel to the ground from an airplane at a cruising altitude of 10,000 meters?
30 seconds
Solar and lunar eclipses are rare because the Moon's orbital plane is tipped by:
5.2° relative to Earth's orbital plane.
At a latitude of +50°, how far above the horizon is the north celestial pole?
50°
The Moon is in synchronous rotation with Earth because
the Moon rotates on its axis once per revolution around Earth.
Compared to the winter, in the summer:
the Sun is higher in the sky at noon.
A line running from due north to due south through a point directly overhead is called
the meridian
If you go out at exactly 9 P.M. each evening over the course of 1 month, the position of a given star will move westward by tens of degrees. What causes this motion?
the revolution of Earth around the Sun
When the moon appears more than half lit, and is becoming more lit every day, which phase is it in?
waxing gibbous
On the celestial sphere, the equinoxes are
where the ecliptic crosses the celestial equator.
When the Northern Hemisphere experiences summer, the Southern Hemisphere experiences:
winter
