The Solar System & Time Flashcards
What is the point where the Sun is furthest from the earth called?
Aphelion
What is the point when the Sun is closest to the earth?
Perihelion
When is the highest speed of the earth in it’s orbit?
At perihelion
When is the lowest speed of the earth in it’s orbit?
At Aphelion
When does Perihelion occur?
January
When does Aphelion occur?
July
What is the cause of the seasons?
The earth’s tilt
When does the NH experienec summer?
When it is tilted most towards the sun
What caused the longer nights in winter and lonber days in summer?
The earth’s tilt.
What is the name given to the apparent path of the Sun on the celestial sphere?
Ecliptic
What is the name given to the orbital path of the earth?
Ecliptic
What is the angle between the plane of the ecliptic and the earth’s equator?
23.5 °
What is the tropic of Cancer?
23.5°N
What is the tropic of Capricorn?
23.5°S
What is the tropic of Capricorn?
23.5°S
What do the tropic of Cancer and tropic of Capricorn represent?
The highest latitudes where the sun will be directly overhead.
What do the tropic of Cancer and tropic of Capricorn represent?
The highest latitudes where the sun will be directly overhead.
What are the Polar circles?
The Arctic circle and the Antarctic circle.
What are the latitudes of the Arctic and Antarctic circles?
65.5°N and 65.5°S
What does the position of the polar circles depend on ?
The earth’s axial tilt.
How much does the earth’s axial tilt vary?
Within a margin of 2° every 40,000 years.
What is the reason for the variation of the earth’s axial tilt?
tidal forces resulting from the moon
What are the frigid zones?
The areas between the polar circles and the poles.
What are the equinoxes?
The times when the relative length of night and day and the elevation of the noon Sun, known as the declination of the Sun, are changing at the greatest rate.
What is Kepler’s first law?
The Orbit of each planet is an ellipse with the Sun at one of the foci.
What is Kepler’s second law?
The line joining the planet to the Sun, know as the radius vector, sweeps out equal area in equal time.
What is Kepler’s third law?
The square of the time a planet takes to go around the Sun is proportional to the cube of its mean distance from the Sun.
How long is a sideral day?
23hrs 56mins 4 secs
What is the analemma?
The position of the noon sun compared with the mean value.
When are the mean sun and the apparent sun farthest apart?
February and November.
