In the Southern Hemisphere, the equal day and night dates arrive before the September equinox and after the March equinox. The schematic below illustrates this situation. They occur because the Earth’s axis of spin lies at an angle (23.5 degrees) to the plane on which it orbits the Sun. The daytime continues to be longer than the nighttime until after the September equinox. The solstices and equinoxes are defined by Earth’s position in its orbit relative to the Sun. Higher latitudes in the Northern Hemisphere experience equal day and night before the March equinox. There is always a long period between sunrise and sunset for observers within a few degrees of the equator. For example, 3:31 am Tuesday, Eastern Time (ET) is 8:31 am Tuesday, Coordinated Universal Time (UTC). Equinoxes mark the beginning of Fall and Spring. Our ancestors lived amidst nature more than most of us do today. Coordinated Universal Time is 5 hours ahead of Eastern Time (ET). 14 hours ago &0183 &32 The solstice marks the start of Summer and Winter. Did you know that the equinoxes and solstices happen at the same moment around the world Even though we all have different time zones, these are astronomical events based on our planet’s orbit around the Sun and tilt on its axis. Every year, it takes place around March 22 and September 22. Solstice is when the earth is farthest from the equatorial plane, lengthening day and night. These times are in Coordinated Universal Time (UTC). Equinox is considered the time of year when the sun is closest to the equatorial plane, giving day and night roughly equal length. The following are the times and dates of equinoxes and solstices from 2017 to 2030. Date and Time for Solstices and Equinoxes These are times when Earth is closest or furthest from the sun (respectively). It is also only a few weeks from this time that the clocks go back marking the beginning of summer time and making the evenings draw in.In addition to equinoxes and solstices, two other astronomical periods occur yearly: perihelion and aphelion. The June solstice is the longest day of the year in the Northern Hemisphere and the shortest day in the Southern Hemisphere. As with the Spring Equinox this is a point of seasonal equilibrium with days and nights being almost exactly 12 hours long each. Eastern time, signals the end of winter and first day of spring in the Northern Hemisphere. The Autumn or Fall Equinox signals the end of Summer on the astronomical calendar. 4 hours ago &0183 &32 The vernal (or spring) equinox, which arrives March 20 at 5:24 p.m. This is the first day of Astronomical Summer and occurs as the sun reaches its most northerly or southerly path in the sky. 2 hours ago &0183 &32 Earth’s tilt and the sun’s alignment over the equator determine solstice and equinox dates. The Summer Solstice is also known as the longest day, which is perhaps the most notable feature. It is around this time of year that the clocks go forward making the evenings stay light and marking the beginning of summer time. In fact the word equinox is taken from the Latin aequus (equal) and nox (night) or "equal night". September Equinox The Sun shines directly on the Equator on the September equinox and the length of day and night is nearly equal, but not quite. This is based upon the formulas given by Jean Meeus in his Astronomical Algorithms. The June solstice is the longest day of the year in the Northern Hemisphere and the shortest day in the Southern Hemisphere. This is the day the sun reaches its northernmost position before it starts getting lower in the sky. It’s the first solstice of the year when the sun’s rays are directly over the Tropic of Cancer. It is also the point in the calendar where the day length is more or less equal to the length of the night. EQNSOL computes the date of equinoxes and solstices for the input year. Two equinoxes occur annually on Earth: one around March 21 and the other around September 22. The Spring or Vernal Equinox marks the astronomical first day of spring.
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