Topic 4; Earth Science

The angular direction of the object above the horizon (vertical angle)

The angular distance around the horizon from some reference point (horizontal angle)

The apparent path of the sun among the stars (West to east)

1) sun takes one year to make a complete circuit of the ecliptic 2) the plane of the ecliptic is inclined at an angle of 23 1/2 degrees to the plane of the celestial sphere 3) the sun is on the celestial equator

- the first day of spring - equal duration of day & night - sun is overhead at noon on equator - sun is on the horizon at the poles - sun rises due east and sets due west - sun's altitude at noon = 48 degrees MARCH 21st.

- the first day of fall - equal duration of day & night - sun is overhead at noon on equator - sun is on the horizon at the poles - sun rises due east and sets due west - sun's altitude at noon = 48 degrees SEPTEMBER 23rd.

- the first day of winter - the earth is closest to the sun (perihelion) - sun is directly overhead during noon at 23.5 degrees south (the tropic of capricorn) - area north of artic circle (66.5 degrees North) is in constant darkness - sun at lowest yearly noon altitude - minimun duration of insolation - sun rises south of eat and sets south of west - sun's altitude at noon = 24.5 degrees DECEMBER 21st.

- the first day of summer - the earth is farthest from the sun (aphelion) - sun is directly overhead during noon at 23.5 north(tropic of cancer) - area north of artic circle (66.5) is at constant light - sun at highest year noon altitude - maximun duration of insolation - sun rises north of east and sets north of west - sun's altitude at noon= 71.5 degrees

Incoming solar radiation

Defined as the time it takes the moon to return to the same position relative to the stars; it is equal to 27 1/3 days

The time from one full moon to the next full moon takes 29.5 days - this is a little longer than the sidereal period because the moon has to "catch up" to the motion of the earth around the sun

The moon is between the earth & the sun in its orbit. we can see NO portion of the moon's surface that is lit. we see only the dark side of the moon

We see a small silver lit moon on the right side

We see the right half of the lit moon. the moon and earth are now "side by side" in thier orbits around the sun

We see almost the entire right side of the lit moon