Sun / Moon Set >>?

Question

If we watch Sun Moon Set over a video recording , mostly, it's motion is never perpendicular to the Horizone , but at an angel other than 90 with horoizon. Is this related with Axial tilt of earh and our location ?
Does , on equator , the "Settings" occur at right angle everyday ?

Answer 1

The daily motion of the Sun and Moon are of course illusions caused by the rotation of the Earth. These motions are always parallel to the equator. The horizon is perpendicular to the equator only if you are at the equator. So you are right when you suggest that the rising and setting would always be perpendicular to the horizon at the equator. The angle of the path of the setting Sun is not related to the axial tilt, only your location on Earth. But the point along the horizon where it finally sets does depend on the axial tilt. If the axis were not tilted, the Sun would always set due west. It would approach that due west point at 90 degrees if you were at the equator, and it would approach that point at an angle equal to 90 minus your latitude if you were not at the equator. At the pole, which is 90 degrees latitude, the Sun would just sit on the horizon all the time, but go around you, just at the horizon, once a day, never rising or setting. Its motion would be parallel to the horizon. This can be seen in reality on the day of an equinox at either pole. If the Earth's axis were not tilted, everyday would be an equinox day, because the Sun would always be on the celestial equator.

Answer 2

The Earth's axis swings through a 47 degree tilt (23.5 degrees north and 23.5 degrees south). Add to that, the Moon's orbital orientation is about 5 degrees off equatorial.

So, the liklihood that you would get a perpendicular setting of both the Sun and the Moon is largely due to what latitude you are, and how the Moon's orientation squares with the Earth and your location. A perpendicular setting of both on the same day would be a long-shot occurance.

Answer 3

Since the earth's axis is tilted, the sun does not travel in a straight line across the sky, and neither do the planets. They follow a line called "The Ecliptic" which is north of the earth's equator during the northern summer and below it in the northern winter. It is this tilt that causes our seasons, not the fact that the earth is closer to the sun during part of it's elliptical orbit.
At the equator the sun is directly overhead only twice a year during the equinoxes.

Answer 4

Somewhat. For you to see the sun go down straight, you would have to be near the equator but actually on the plane of inclination, the axial tilt plane. The value changes a bit, as there are long term tilt changes and short term tilt changes as well as the revolution of the earth around the sun, our year. The tilt in relation to the sun gives us a wobble as it were but not a true one, just one perceived as we circle. So you would have to chart it and figure it daily to be in the right place to see the sun go straight down.