First, planets vary in their axial tilts: Venus's axis of rotation is tilted by just three degrees, so there's much less seasonal difference between the Venusian summer and winter solstices than those on Earth.
In addition, planets such as Mars have less circular orbits than Earth's, which means that their distances from the sun vary more dramatically than ours do, with correspondingly bigger effects on seasonal temperature. Earth makes its closest annual approach of the sun about two weeks after the December solstice , during the Northern Hemisphere's winter.
Earth is farthest from the sun about two weeks after the June solstice, during the Northern Hemisphere's summer. For millennia, cultures around the world have devised ways to celebrate and revere these celestial events—from building structures that align with the solstice to throwing raucous festivals in its honor. Though the purpose of the enigmatic English structure Stonehenge remains unknown, this 5,year-old monument has a famously special relationship with the solstices.
In Egypt, the Great Pyramids at Giza appear to be aligned with the sun as well. When viewed from the Sphinx, the sun sets between the pyramids of Khufu and Khafre during the summer solstice—though it remains unclear precisely how the ancient Egyptians oriented it this way. Many cultures have found unique ways to mark the summer solstice.
The traditional Scandinavian holiday of Midsummer welcomes it with maypole dancing, drinking, and romance. During the Slavic holiday of Ivan Kupala , people wear floral wreaths and dance around bonfires, while some plucky souls jump over the fires as a way of ensuring good luck and health. In a more modern tradition, the people of Fairbanks, Alaska, swing in the summer solstice with a nighttime baseball game to celebrate the fact that they can get up to The Midnight Sun Game has been played times now since The winter solstice has had its share of celebrations, too.
The festival is still celebrated throughout the Andes, and since , a reconstruction of Inti Raymi has been staged in Cusco, Peru, less than two miles from its Inca Empire home. Ancient Romans celebrated the winter solstice with Saturnalia , a seven-day festival that involved giving presents, decorating houses with plants, and lighting candles.
And Iranians celebrate Yalda in December. In the U. Likewise, thermometers hit their high in the U. Growth lines on fossil corals show that more than million years ago, days on Earth lasted less than 22 hours.
Picture a figure skater twirling on their skates; they can speed up or slow down their twirls by how much they tuck in their limbs. It lasted less than four milliseconds longer than the recent average. All rights reserved. What are solstices? The solstice through history.
And, likewise, they think Earth is farthest from the Sun in the winter. It is true that Earth's orbit is not a perfect circle. It is a bit lop-sided. During part of the year, Earth is closer to the Sun than at other times.
However, in the Northern Hemisphere, we are having winter when Earth is closest to the Sun and summer when it is farthest away! Compared with how far away the Sun is, this change in Earth's distance throughout the year does not make much difference to our weather. Earth's axis is an imaginary pole going right through the center of Earth from "top" to "bottom. That is why we have day and night, and why every part of Earth's surface gets some of each.
Long, long ago, when Earth was young, it is thought that something big hit Earth and knocked it off-kilter. All the light is still in that ellipse, but the ellipse is spread out over more paper. The density of light drops.
In other words, the amount of light per square centimeter drops the number of square centimeters increases, while the total amount of light stays the same. The same is true on the earth.
When the sun is overhead, the light is falling straight on you, and so more light and more heat hit each square centimeter of the ground. When the sun is lower in the sky, the light gets more spread out over the surface of the earth, and less heat per square centimeter can be absorbed. Since the earth's axis is tilted, the sun is higher when you are on the part of the earth where the axis points more towards the sun, and lower on the part of the Earth where the axis points away from the sun.
For the Northern Hemisphere, the axis points most toward the sun in June specifically around June 21 , and away from the sun around December This corresponds to the Winter and Summer Solstice solstice is Latin for "the sun stands".
For the Southern Hemisphere, this is reversed. For both hemispheres, the earth is 90 degrees away from the sun around March 21 and then again around September This corresponds to the Fall and Spring Equinox equinox is Latin for "equal night". Everyplace in the world has about 12 hours of daylight and 12 hours of night. Day and night are not exactly of equal length at the time of the March and September equinoxes. The dates on which day and night are each 12 hours occur a few days before and after the equinoxes.
The specific dates for this occurrence are different for different latitudes. On the day of the equinox, the geometric center of the Sun's disk crosses the equator, and this point is above the horizon for 12 hours everywhere on the Earth.
However, the Sun is not simply a geometric point. Sunrise is defined as the instant when the leading edge of the Sun's disk becomes visible on the horizon, whereas sunset is the instant when the trailing edge of the disk disappears below the horizon. At these times, the center of the disk is already below the horizon. Furthermore, atmospheric refraction or bending of the Sun's rays cause the Sun's disk to appear higher in the sky than it would if the Earth had no atmosphere.
Thus, in the morning, the upper edge of the disk is visible for several minutes before the geometric edge of the disk reachs the horizon. Similarly, in the evening, the upper edge of the disk disappears several minutes after the geometric disk has passed below the horizon. For observers within a couple of degrees of the equator, the period from sunrise to sunset is always several minutes longer than the night.
At higher latitudes in the Northern Hemisphere, the date of equal day and night occurs before the March equinox. Daytime continues to be longer than nighttime until after the September equinox.
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