waxing: Waxing essentially means "growing" or expanding in illumination.
waning: Waning means "shrinking" or decreasing in illumination.
gibbous: The word gibbous refers to phases where the moon is more than half illuminated.
crescent: The word crescent refers to the phases where the moon is less than half illuminated.
When i see a waxing moon, it looks like the moon is enlarging day by day.
lunar cycle: a period of time at the close of which the new moons return on the same days of the year.
A lunar cycle lasts for 29.5 days.
Nicolai Copernicus was famous for proposing the idea of the sun being the center of our solar system instead of the Earth.
Why do we have seasons? We have seasons because the Earth rotates on an axis that is tilted in its orbit. The 23.5 degree tilt causes the different hemispheres to be at different angles to the sun at different times of the year.
In the winter, even though we are closest to the sun, because of the angle, the energy from the sun must travel through more atmosphere to reach the poles.
The reason why we don't have a lunar eclipse each month is because the Earth and moon's orbit is always tilted 5 degrees in a direction so that means the sun, moon, and earth are not all aligned at the same time.
We have day and night because the Earth rotates and spins on it's axis.
Equinox: Either of the two times during a year when the sun crosses the celestial equator and when the length of day and night are approximately equal; the vernal equinox or the autumnal equinox.
Solstice: Either of two times of the year when the sun is at its greatest angular distance from the celestial equator. The summer solstice in the Northern Hemisphere occurs about June 21, when the sun is at the zenith on the Tropic of Cancer; the winter solstice occurs about December 21, when the sun is at zenith on the Tropic of Capricorn. The summer solstice is the longest day of the year; the winter solstice is the shortest.