The subsolar point on a planet is where its sun is perceived to be directly overhead (in zenith), that is where the sun's rays are hitting the planet exactly perpendicular to its surface. It can also mean the point closest to the sun on an object in space, even though the sun might not be visible.
For planets with an orientation and rotation similar to the Earth's, the subsolar point will move westward, circling the globe once a day, but it will also move north and south between the tropics over the course of a year. The December solstice occurs when the subsolar point is on the Tropic of Capricorn and the June solstice is at the instant when the subsolar point is on the Tropic of Cancer. The March equinoxes and September equinoxes occur when the subsolar point is on the equator.
The subsolar point is frequently used in celestial navigation and the coordinates of the subsolar point at various times throughout the year (often every hour) can be found in a nautical almanac.
When the point passes through Hawaii, it is known as Lahaina Noon.
Famous quotes containing the word point:
“At this age [9–12], in contrast to adolescence, girls still want to know their parents and hear what they think. You are the influential ones if you want to be. Girls, now, want to hear your point of view and find out how you got to be what you are and what you are doing. They like their fathers and mothers to be interested in what they’re doing and planning. They like to know what you think of their thoughts.”
—Stella Chess (20th century)