Chapter 1 Flashcards
What is the celestial sphere
The celestial sphere is a 3D model that surrounds the earth and lets us place and observe celestial objects
Does the celestial sphere match physical reality?
No, it does not necessarily match physical reality.
What are constellations
Constellations are an arrangement of stars that connect to represent an animal, object, or mythological figure.
Are the stars in a constellation physically related?
No, they are not physically related. They can be light years apart and differentiate in size as well.
Do constellations change?
Stars move very slowly, constellations stay the same for thousands of years.
What were constellations used for
Their origin is unknown, but they seem to have been used for navigation and tracking the seasons
Is the sky different day to day? Month to month? Year to year?
The sky is not different day to day, it is different month to month, and it is not different year to year.
What is diurnal motion
Diurnal motion or “daily motion” is the movement of the sun, moon, and stars. They rise from the east and set in the west, this is due to earth’s rotation.
What is annual motion?
Annual motion or “yearly motion” is the movement of the earth due to its revolution around the sun.
What is the explanation of daily motion?
Daily motion is the rotation of the celestial sphere upon the celestial poles
What are the celestial poles
The celestial poles are imaginary poles extending from the north and South Pole
What is the celestial equator
The celestial equator is an imaginary equator line directly above the earths equator
What is the ecliptic
The ecliptic is the path the sun takes around the earth and through the celestial sphere.
What causes the seasons?
The seasons are caused by whether the earths axis is pointing towards or away from the sun. It is not caused by earths proximity to the sun.
What is the earths axial tilt?
23.5 degrees
What is the position of the sun in correspondence to the celestial equator in June and December
In June the sun is above the celestial equator, and in December it is below
Where does the sun rise from and set in the summer months?
It rises from north of east and sets north of west
Where does the sun rise and set from in winter months
It rises from the south of east and sets south of west
What is the solstice, from when to when does it occur
Solstices are from 21 of June to 21 of December, they are when the sun is at the highest point in the sky
What is the equinox? When does it happen
The equinox is when there are equal day and night times, happens from march 21 to September 23
What are the phases of the moon in order
New, waxing crescent, first quarter, waxing gibbous, full, waning gibbous, third quarter, waning crescent
What is an eclipse and when does it occur
An eclipse is when the sun, earth, and moon directly align with each other. It completely covers a spot on earth in darkness.
Do we have a solar and lunar eclipse every month?
Because of the tilt of the moon, eclipses will not always happen, and it is rare for a total eclipse to happen.
What is an eclipse season
It is when it is the most possible time for an eclipse to do, two times a year.
