Questions and Answers
Like Latitude on Earth, __________ in the sky is measured in degrees north and south of the equator.
Declination
The 12 constellations that the sun passes are signs of the ________.
Zodiac
The time interval of 365.242 days is defined as _______.
Tropical Year
The time for the moon to orbit the Earth relative to the distant stars is ______________.
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What is the apparent annual path the sun takes through the sky?
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If the moon rises at sunset, then its phase must be __________.
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If the new moon is on the ecliptic, new, and at its farthest distance from Earth, we will get a ____________ solar eclipse.
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Our seasons are a consequence of the Earth's 23.5 degree ________.
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Over the course of the year, the sun's noon altitude varies by ______.
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That we don't get eclipses every new and full moon is due to the ______ tilt of the moon's orbit.
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A distance of ten trillion kilometers in astronomy is called a ______.
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The apparent angular shift of any object across a distant background, when viewed from 2 different places is called a ___________.
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Sirius has a parallax of 0.38, while Alpha Centauri is 0.77. Alpha Centauri is about ___________ as Sirius.
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If one star has a parallax 10x larger than another, the first star is ________.
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What is an imaginary hollow sphere with the Earth at the center on which all stars are fixed?
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Which is longer: sidereal or solar day?
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At the solstice, what is the maximum distance (angle) the sun can be above or below the equator?
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Which star shows the least motion in the northern sky over the course of an hour?
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How far above or below the equator can the sun appear to move? Why?
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What happens on March 20th?
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If the moon rises exactly at sunset, what will the phase be?
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Why is Polaris not always the North Star and when does it get another chance?
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Study Notes
Astronomy Terms and Concepts
- Declination: Measures celestial objects' position in degrees north or south of the celestial equator, similar to latitude on Earth.
- Zodiac: Refers to the 12 constellations that the sun transitions through annually, which are known as the signs of the zodiac.
- Tropical Year: Defined as the time interval of approximately 365.242 days, marking one complete cycle of seasons.
- Sidereal: Pertains to the moon's orbital period around Earth, measured in relation to distant stars.
- Ecliptic: The apparent annual path traced by the sun across the sky throughout the year.
Lunar Phases and Eclipses
- Full Moon: Occurs when the moon rises at sunset, indicating that it is opposite the sun in the sky.
- Annular Eclipse: Happens when a new moon aligns on the ecliptic and is at its farthest distance from Earth, resulting in a ring-like appearance.
Earth and Seasons
- Axial Tilt: Earth's tilt of approximately 23.5 degrees influences the changing seasons throughout the year.
- Sun's Noon Altitude: Fluctuates by 47 degrees over the year, affecting sunlight distribution and seasonality.
Eclipses and Orbits
- Orbital Tilt: The reason eclipses do not occur each new and full moon is due to the moon's orbital tilt of 5.2 degrees.
- Light Year: A unit of distance equivalent to about ten trillion kilometers, often used to measure astronomical distances.
- Parallax: Describes the apparent angular shift of an object against a distant background, observed from two different positions.
Stellar Distances and Motion
- Sirius and Alpha Centauri: Sirius exhibits a parallax of 0.38, making it twice as close to Earth as Alpha Centauri, which has a parallax of 0.77.
- Parallax Comparison: A star with a parallax ten times larger than another is ten times closer to Earth.
Celestial Sphere and Observation
- Celestial Sphere: An imaginary sphere with Earth at the center, where all stars appear fixed for observational purposes.
Time Measurement
- Sidereal vs. Solar Day: A solar day is about four minutes longer than a sidereal day, accounting for Earth's rotation and orbit.
- Solstice Sun Position: At the solstices, the sun can reach a maximum angle of +23.5 degrees during summer and -23.5 degrees during winter relative to the equator.
North Star and Equinox
- Polaris: Known as the North Star, it shows minimal motion in the northern sky over an hour due to its alignment with Earth's rotational axis.
- Sun's Movement: The sun can move 23.5 degrees north or south of the equator due to Earth’s axial tilt.
- March 20th: Marks the vernal equinox when day and night are of equal length, indicating a change of seasons.
Lunar Phases and Historical Astronomy
- Moon Phase at Sunset: If the moon rises at sunset, it is in its full phase, positioned opposite the sun.
- Precession of the Equinoxes: Polaris is not always the North Star due to this cycle, which occurs every 26,000 years, allowing different stars to take its place over millennia.
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Description
Test your knowledge on fundamental astronomy concepts in this quiz. Explore terms like declination, zodiac, and the tropical year. Perfect for beginners looking to enhance their understanding of celestial movements.
