During this time, one hemisphere will be experiencing warmer temperatures and longer days while the other will experience colder temperatures and longer nights. Instead, at any given time of the year, one hemisphere is pointed slightly more towards the Sun, leaving the other pointed away. 12 hours of day and night, respectively) every day during the year and there would be no seasonal variability. If the Earth’s axis were perpendicular to its orbital plane around the Sun, all places on Earth would experience equal amounts of day and night (i.e. Axial Tilt:Īs already noted, due to the Earth’s axial tilt (or obliquity), day and night are not evenly divided. The northern axis points outward to Polaris, hence why it is called “the North Star”, while its southern axis points to Sigma Octantis. What’s more, its central axis is aligned with two stars.
The Earth rotates once in about 24 hours with respect to the Sun and once every 23 hours 56 minutes and 4 seconds with respect to the stars. However, viewed from the southern polar region, it appears to be rotating clockwise.Įarth’s axial tilt and its relation to the rotation axis and plane of orbit as viewed from the Sun during the Northward equinox. If you could view the Earth from above, looking down at the northern polar region, the planet would appear to be rotating counter-clockwise. Earth’s Rotation:Įarth’s rotation occurs from west to east, which is why the Sun always appears to be rising on the eastern horizon and setting on the western. And two, the fact that Earth’s axis is tilted. Namely, what causes the cycle of day and night, and why don’t all places on the planet experience the same patterns? As with many other seasonal experiences, the answer has to do with two facts: One, the Earth rotates on its axis as it orbits the Sun. Naturally, this gives rise to certain questions. And there are also seasonal periods where a single night can last many days.
the poles) the Sun does not set during certain times of the year. As a result of seasonal changes that happen with every passing year, the length of day and night can vary – and be either longer or shorter – by just a few hours. the diurnal cycle) are just simple facts of life. For most of here on planet Earth, sunrise, sunset, and the cycle of day and night (aka.