![]() ![]() The Earth rotates around its axis, spinning like a top. The Earth moves in two ways – rotation and revolving – here’s what the two mean Rotation Similarly, the equinoxes and solstices are dependent on the Earth’s revolution around the sun. Have you ever thought if we have a signal for the change in seasons? To understand all this, one needs to understand the Earth’s orbit and how it functions. Have you ever wondered why is there more daylight in summer than in winter? You would have seen a lot of different kinds of seasons in a year – have you ever thought about why seasons change? The equinoxes happen twice a year– once on 21 March and once on 23 September. The Equinox – either of the two times in a year when the Sun is right above the Equator and day and night are of equal length. This is marked by the longest and shortest days in the year (about 21 June and 22 December). The Solstice – either of the two times in a year when the Sun’s path is as far north or as far south from the Earth’s Equator. What’s the difference between a Solstice and an Equinox? Both are periodic solar events that happen on the same date every year. You’ll see that the difference lies in their very definitions. At the same time, the Southern Hemisphere is tilted away from the sun and experiencing winter.Written by Saanchi Biyani, a grade 5 student.įirst, here’s what they both mean – and you’ll see the difference. When the Northern Hemisphere is tilted toward the sun, latitudes between the equator and 90°N (the North Pole) are experiencing summer. The combination of more direct rays of sunlight and more hours of daylight causes the hemisphere tilted toward the sun to receive more solar radiation and to have warmer temperatures. The hemisphere tilted toward the sun also has more hours of daylight than the hemisphere that is tilted away from the sun. Whichever hemisphere (the Northern or Southern Hemisphere) is tilted toward the sun receives more direct rays of sunlight (or rays that are closer to perpendicular or a 90° angle). Earth is actually a little farther from the sun when the Northern Hemisphere is having summer. This is a misconception because Earth's orbit is only slightly elliptical and our planet is nearly the same distance from the sun all year long. People often mistakenly think that the different seasons are caused by a change in Earth's distance from the sun. Similar to the previous graphic but this perspective is vertical and looking down at the North Pole. Because the direction and angle of the axis of rotation do not change, the Northern Hemisphere is tilted toward the sun during part of the year and away from the sun during another part of the year. The direction and angle (or tilt) of Earth's axis of rotation do not change as Earth revolves around the sun. When we add a day every 4 years to align the calendar, this year is often called a leap year.Īt the present time, Earth is tilted on its axis of rotation by 23.5°. To keep our calendars synchronized with the planet's actual orbit, every 4 years we add an extra day to the month of February – 4 quarters of a day (1 quarter each year for 4 years) equals 1 day or 24 hours. Earth takes 365 and ¼ (6 hours) days to complete one revolution around the sun. ![]() Like the other planets, Earth rotates on its axis as it revolves around the sun. ![]() This is a horizontal perspective facing the equator. This graphic shows Earth with its 23.5° tilt, the direction of its rotation and the pattern of the seasons as it travels around the sun. ![]()
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