Flashcards in Chapter 1 Deck (39)
In the sky, declination is measured in degrees north or south of the celestial equator.
In reality, the Moon’s orbit about Earth is tilted (by about 5°) 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.
1. As the distance of the object increases, parallax decrease
2. As the size of the baseline increases, parallax decreases
3. As the distance to the background objects increase, parallax remains the same
Consider the Moon and Sun. Their angular diameters are both equal to about .5 degree. If the Sun is roughly 400 times more distant than the Moon, how much bigger is the Sun’s diameter than the Moon’s?
about 400 times bigger
While watching a star, you see it moves 15 degrees across the sky. How long have you been watching it?
How does the parallax of a nearby object compare to that of an object farther away?
The nearby object exhibits a larger parallax than the farther object.
Which of the following is NOT true of the celestial equator?
It traces the path of the Sun among the constellations.
The south celestial pole is located at a declination of -90 degrees.
In the summer we observe different constellations than in the winter. This is because ________.
Earth has moved to the other side of its orbit
The closest terrestrial analog to hours of right ascension is angle of longitude.
A sidereal day is shorter than a solar day because ________.
Earth is moving around the Sun
The angular diameter of an object is inversely proportional to its distance from the observer.
Arrange the following objects in order of increasing size.
Earth, Solar System, Galaxy, Universe
Night and day have approximately equal length at what time or times of the year?
Vernal and autumnal equinoxes
A solar eclipse can only happen during a:
How long is the precession cycle?
The star Wolf 1061 has a parallax of 2.34 arcseconds, while the star Ross 652 has a parallax of 1.70 arcseconds. What can you correctly conclude?
Wolf 1061 is closer to Earth than Ross 652.
What is the cause of the phases of the Moon?
As the Moon orbits the Earth, different parts of the side facing the Earth are illuminated by the Sun.
If the Moon rose tonight at 6 PM, then tomorrow it will rise about:
At the solstices, the Sun's declination will be 23.5 degrees from the equator.
The stars in a constellation are physically close to one another.
Which of the following describes parallax?
It is inversely proportional to the distance to the star.
The constellations are ________.
arbitrary regions that cover the entire sky, which astronomers have named
A lunar eclipse can occur only during the full phase.
The sidereal day is determined by the Earth's rotation with respect to the stars.
Where on Earth can you observe all the stars in the sky over an entire year?