What is an equinox?

Answer 1

An Equinox happens when the sun is directly over the equator......it happens twice a year on March 20 and September 23rd............This is when the length of the days and nights are equal...........

Answer 2

An equinox in astronomy is the event when the Sun can be observed to be directly above the equator. The event occurs twice a year, around March 20 and September 23. More technically, the equinox happens when the Sun is at one of two opposite points on the celestial sphere where the celestial equator and ecliptic intersect. In a wider sense, the equinoxes are the two days each year when the center of the Sun spends an equal amount of time above and below the horizon at every location on Earth. The word equinox derives from the Latin words aequus (equal) and nox (night).

In practice, at the equinox, the day is longer than the night. Commonly the day is defined as the period that sunlight reaches the ground in the absence of local obstacles. This is firstly because the Sun is not a single point of light, but appears as a disc. So when the center of the Sun is still below the horizon, the upper edge is already visible and sheds light. Furthermore, the atmosphere refracts light downwards, so even when the upper limb of the Sun is still below the horizon, its rays already reach around the horizon to the ground. These effects together make the day about 14 minutes longer than the night (at the equator, and more towards the poles). The real equality of day and night happens a few days towards the winter side of the equinox.

Note: Equal nights is an abstraction strictly speaking only true when Earth and Sun are considered particles, that is ignoring atmospheric effects, parallax, perturbations, et cetera, (as discussed below). It is not supposed to be exactly measurable.

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Answer 3

An equinox in astronomy is the moment when the Sun can be observed to be directly above the equator. The event occurs twice a year, around March 20 and September 23. More technically, the equinox happens when the Sun is at one of two opposite points on the celestial sphere where the celestial equator and ecliptic intersect. In a wider sense, the equinoxes are the two days each year when the center of the Sun spends an equal amount of time above and below the horizon at every location on Earth. The word equinox derives from the Latin words aequus (equal) and nox (night).

Answer 4

The time when the sun crosses the earth's equator, making night and day of approximately equal length all over the earth and occurring about March 21 (the spring or vernal equinox) and September 22 (autumnal equinox).

Answer 5

An equinox in astronomy is the event when the Sun can be observed to be directly above the equator. The event occurs twice a year, around March 20 and September 23

Answer 6

equinox -noun- the time when the sun crosses the plane of the earth's equator, making night and day of approximately equal length all over the earth and occurring about March 21 (vernal equinox or spring equinox) and September 22 (autumnal equinox).

Answer 7

Two days in 1 year are equinoxes. They are when the length of the night and day are equal! (12 hours)

Answer 8

It is a period of the year where the night and the day have the same duration (12 hours) Equinoxe in latin means equality of night and day.

This period In northern hemisphere takes place the 21 of march (spring) and the 23 of september (autumn)

Answer 9

Time of year when there is equal amount of day and equal nights (12 hours of daylight, 12 hours of night). Vernal equinox and autumnal equinox.

Answer 10

It a day on which the length of day and night are equal all over the world. It is also is the date on which the sun is directly above the equator. It occurs on March 21 and September 21 give or take a day.