Mastering Astronomy~Chapter: 0-copy

Flashcard maker : Isabel Padilla
Suppose that instead of being inclined to Earth’s orbit around the Sun, the Moon’s orbit was in the same plane as Earth’s orbit around the Sun. (Click “Show Moon with flat orbit” to see this situation.) In this hypothetical situation, approximately how many solar eclipses would occur each year?
In reality, the Moon’s orbit about Earth is tilted (by about 5Ā°) with respect to Earth’s orbit about the Sun. As a result, the actual number of solar eclipses that occur each year is approximately _____.
What conditions must exist for a solar eclipse to occur?
The phase of the Moon must be new and the Moon must be passing through Earth’s orbital plane.
What conditions must exist for a lunar eclipse to occur?
The phase of the Moon must be full and the Moon must be passing through Earth’s orbital plane.
If you could change the layout of the solar system, which of the following would cause a lunar eclipse to occur at least once every month in this hypothetical situation?
Change the Moon’s orbital plane so it is in the same plane as Earth’s orbit around the Sun.
Vocabulary in Context: Describing Eclipses of the Sun and Moon
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The stars in a constellation are physically close to one another.
The seasons are caused by the precession of Earth’s axis.
A lunar eclipse can occur only during the full phase.
If we know the distance of an object from Earth, we can determine the size of the object by measuring its parallax.
When a thin crescent of the Moon is visible just before sunrise, the Moon is in its
Waning Phase
If the Moon’s orbit were a little larger, solar eclipses would be
More likely to be annular
The greatest distance above or below the ecliptic the Moon can move is
5.2 Degrees
In an annular eclipse,
the Sun appears as a thin, bright ring.
If you are in the Earth’s umbra, then
it is night time.
The synodic month is
29.5 Days
If the Moon appears half lit, and is almost overhead about 6:00 AM, its phase is
Third Quarter
A solar eclipse can only happen during a:
New Moon
What will occur when the full moon is on the ecliptic?
A Total Lunar Eclipse
If you are in the Moon’s umbral shadow, then you will witness
A Total Solar Eclipse
The time for the Moon to orbit Earth, relative to the stars is
27.3 Days
If Taurus is now rising at sunset, which constellation will rise at sunset next month?
The fact that the Earth has moved along its orbit in the time it took to rotate once is the reason for
the difference between solar and sidereal time.
When the Moon is directly opposite the Sun in the sky, its phase is
You note that a particular star is directly overhead. It will be directly overhead again in
23 hours 56 minutes.
That Polaris will not always be the pole star is due to
precession shifting the celestial pole.
The 26,000 year cycle that changes the poles and equinoxes is called
The twelve constellations the solar system bodies move through are the
signs of the zodiac
What are constellations?
Groups of stars making an apparent pattern in the celestial sphere
Into how many constellations is the celestial sphere divided?
In general, what is true of the alpha star in a constellation?
It is the brightest star in the constellation
Right ascension in the sky is very similar to latitude on the Earth.
Latitude and right ascension are coordinate systems used to find objects on the Celestial Sphere.
The celestial sphere is divided into 88 modern constellations.
In the sky, declination is measured in degrees north or south of the celestial equator.
The south celestial pole is located at a declination of -90 degrees.
In general, the brightest star in a given constellation is designated as alpha.
Constellations are close clusters of stars, all at about the same distance from the Sun.
The closest terrestrial analog to hours of right ascension is angle of longitude.
A tropical year is the same as a sidereal year.
The sidereal day is determined by the Earth’s rotation with respect to the stars.
The vernal equinox marks the beginning of spring in the northern hemisphere.
From Earth, the Sun and Moon have about the same angular diameter.
At the solstices, the Sun’s declination will be 23.5 degrees from the equator.
At the equinoxes, the declination of the Sun must be zero degrees.
From full moon to third quarter moon takes about a week.
Only people in the Moon’s umbral shadow can see a total solar eclipse.
If we are the Moon’s penumbra, then we will see a partial lunar eclipse.
There is a solar eclipse of some kind every new moon.
A total solar eclipse will only occur when the new moon is both on the ecliptic and at its greatest distance from Earth.
The larger the parallax shift, the closer an object is to us.
The parallax shift for all stars is very small.
Increasing the baseline will increase the parallax angle.
In the scientific method, it is not necessary to test your theory.

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