Why length of day and night is same in spring and autumn?

Answer 1

On the spring equinox, the Sun is moving into your hemisphere and marks the beginning of spring. In the fall equinox, the Sun is moving into the opposite hemisphere, and marks the beginning of fall. In the northern hemisphere, the spring equinox occurs about March 21, and in the Southern Hemisphere, the spring equinox happens about September 21.

Answer 2

The length of day and night is nearly equal during the spring and autumn equinoxes because of the way the Earth is positioned in relation to the sun. During these times, the Earth's axis is neither tilted towards nor away from the sun, resulting in nearly equal amounts of daylight and darkness across the globe.

Answer 3

At the equinoxes, about March 21 and September 21. However, if you want to get precise, on the equinoxes the days are actually a little longer than the nights - because the Earth's atmosphere bends sunlight down and around the Earth. When we see the sunrise, the Sun is actually about a degree and a half below the horizon! And as the Sun is setting, the atmosphere bends the sunlight around keeping the day from slipping away for a few precious moments. So, on the equinoxes, the day length is actually about 10 minutes longer than the night!

The Earth's atmosphere does a better job of bending red light than blue light; that's why sunrises and sunsets are red.

Answer 4

The times of year when the days and nights are equal length is known as the equinox (literally means equal night).

For 2010 the Vernal Equinox is March 20th and the Autumnal Equinox is September 23rd.

Answer 5

These dates are called "equinox", from the Latin root "equi" for equal, and "nox" for night; "equal nights". Those dates are generally March 21 and September 21, although the dates may slide one day back or forward depending on the cycle of leap years.

But it isn't QUITE "equal"; on the equinox, the day is a little bit longer than the nights, because the Sun's light is refracted slightly AROUND the curve of the Earth by our atmosphere. When you see the Sun peek over the horizon, it is actually about 1 degree BELOW the horizon; but the light has been refracted or belt around the Earth by the atmosphere.

A:Neglecting atmospheric effects, the lengths of sun-up and sun-down are equal at

every place on earth at the time of the equinoxes ... March 21 and September 21.

A:The Autumnal and Vernal Equinox. A:Equal periods of sun-up and sun-down are all near March 21 and September 21,

everywhere on earth, including the equator.

A:Those days are often called the "equinoxes", but the equinoxes are actually the

points in the sky where the sun appears to be located on those days.

Answer 6

This happens at both the vernal and autumnal equinoxes.

The equinoxes are the points in the earth's orbit of the sun when the Sun is positioned directly over the Earth's equator. This only happens twice a year because the earths axis of rotation is inclined approximately 23.44° from the plane of the orbit round the sun. Thus when the north pole is pointing at the sun the south pole is permanently in darkness and at the other end of the orbit when the south pole is pointing at the sun the north pole is permanently in darkness - this gives us summer and winter.

Now when the earth is 1/2 way between summer and winter positions (a day in spring and autumn) the axis of rotation is not pointing at the sun at all which means that both the north and south poles are illuminated evenly and each get 12 hours of daylight and 12 hours of night. This happens all over the planet and is the day of the equinox equinox.

Answer 7

At the equinoxes, day and night are approximately the same length. The equinoxes are the beginning of Spring (around March 21 in the northern hemisphere), and the beginning of Autumn (around September 23 in the northern hemisphere). I said "approximately" because day and night are not exactly equal, due to the diameter of the Sun, and refraction in the atmosphere. dummy

ITS EXUINOX

Answer 8

At the "equinox"; "equi-" from "equal", and "nox" from the Latin word for "night". The equinoxes are generally on March 21 and September 21 each year, plus or minus one day because of the cycle of leap years. The US Naval Observatory has a web site for "Earth's Seasons" at which you can see the precise times of the solstices and equinoxes.

Answer 9

Spring occurs on the Vernal Equinox, and in the US it usually falls around March 21. Spring (and Autumn) is when the day and the night are approximately the same length. Summer Solstice is when the longest day of the year and Winter Solstice is the shortest day of the year.

Answer 10

The Earth is tilted on its axis by about 23.44°. As it orbits the Sun sometimes it is tilted towards it and sometimes it is tilted away from it. In relation to the sun, those tilts are at maximum in June and December. As we are in early January, it is more tilted away from it, giving the northern hemisphere less hours of daylight, while the southern hemisphere has more, but each day that is changing. As we continue on our orbit, we come to two points when no part of the planet is tilted more towards the sun. These are the equinoxes. Earth is still tilting, but that tilt is now parallel to the sun. Earth is tilting forward, but the sun is either to its left or its right, depending on which equinox we are at. At that time, the lengths of night and day are more balanced around the planet. In March and September we have the equinoxes, halfway between solstices.