We know that the Earth has several movements that are those of rotation and translation. By this we mean that due to these movements, there are solstices and equinoxes. An equinox is a time of year when the sun is located exactly above the equator, so it is positioned over the zenith. This means that the day and the night have almost the same duration. The opposite occurs with the solstice.
In this article we are going to tell you all the characteristics and differences between solstices and equinoxes.
What are the solstices and equinoxes
Equinoxes
The first of all is to know what the solstices and equinoxes are. An equinox is when the sun is located on the equator and the day lasts the same as the night. That is, they last approximately 12 hours. This happens twice a year, around March 20 and September 22, coinciding with the beginning of spring and autumn in some regions, depending on the context of the seasons.
If we divide the planet into two halves, one is illuminated by sunlight and the other is obscured. In one we have the day and in the other the night. The dividing line passes right through the poles. This occurs because during the equinoxes both poles are not tilted towards or away from the sun. It doesn't always happen on the same day. They have a margin of several days. This is because the length of the years is not always the same. Remember that every 4 years if you add one more day to the calendar because it is a leap year. During the equinoxes the sun is located at one of the two points on the sphere where the celestial equator and the ecliptic intersect. This corresponds to a circle in the same plane as the equator. That is, the projection of the terrestrial equator is the celestial sphere.
The vernal equinox occurs when the sun moves northward in the plane of the ecliptic and crosses the entire celestial equator. Here we see that the spring season begins in the northern hemisphere. For more information on this phenomenon, you can consult our article on the spring equinox. On the other hand, the autumn equinox occurs when the sun moves south across the celestial equator. It marks the beginning of autumn, a phenomenon that can be compared to that of the spring.
Solstices
Solstices are events in which the sun reaches its highest or lowest point throughout the year in the sky. In a year in the Northern Hemisphere there are two solstices. On the one hand we have the summer solstice and on the other hand the winter solstice. The first takes place on June 20-21 and the winter solstice on December 22-22. During both solstices, the sun is located on one of the two imaginary lines on Earth that are known as the Tropic of Cancer and the Tropic of Capricorn. When the sun has set over the Tropic of Cancer is when the summer solstice takes place and when it is located in the Tropic of Capricorn, winter begins.
During the first solstice it is where we find the longest day of the year, while the second is the shortest day and the longest night. One of the aspects that may be of interest about these phenomena is how they relate to the tilt of the Earth and the length of the seasons, as well as how these changes affect our seasons and schedules.
Solstices and equinoxes of summer and winter
Summer Solstice
It is often thought that that day, the first of the summer season, is the hottest. But it doesn't really have to. The Earth's atmosphere, the land we walk on and the oceans absorb part of the energy from the solar star and store it. This energy is released again in the form of heat; however, keep in mind that While the heat is released from the earth fairly quickly, the water takes longer.
During the big day, which is the summer solstice, one of the two hemispheres receives the most energy from the Sun of the year, since it is closer to the sun and therefore the rays of the aforementioned star arrive more straight. But the temperature of the oceans and the land are still relatively mild, for the moment, which is related to the phenomenon of the solsticesTo better understand how these variations occur, review our article on the seasons.
Solstices and equinoxes: winter solstice
Planet Earth reaches a point on its path where the Sun's rays strike the surface in the same way more oblique. This happens because the Earth is more inclined and the rays of the Sun hardly arrive perpendicularly. This causes fewer hours of sunlight, making it the shortest day of the year. For more information on the winter solstice, see our article dedicated to the Winter Solstice.
There's a misconception in general society about winter and summer depending on the Earth's distance from the Sun. It's assumed that summer is hotter because the Earth is closer to the Sun, and winter is colder because we're farther away. But the opposite is true. More than the Earth's position relative to the Sun, what influences the planet's temperatures is the angle at which the Sun's rays strike the surface. In winter, at the solstice, Earth is closest to the Sun, but its tilt is the highest in the Northern Hemisphere. Therefore, when rays reach the Earth's surface at a very steep angle, the day is shorter and they are also weaker, so they don't heat the air as much, making it colder. Here, it's important to consider how this angle relates to the .
Spring and Autumn Equinoxes
Here we must distinguish the equinoxes according to the hemisphere where we are. On the one hand, the northern hemisphere, when it is the vernal equinox we have that at the pole North a day will last 6 months, while at the South Pole, a night will last 6 months. I also have to keep in mind that autumn is just beginning in the southern hemisphere. Knowing these differences is crucial to understanding the seasonal changes.
As you can see, the solstices and equinoxes are primarily due to the Earth's movement relative to the sun, and temperatures and environmental conditions depend on the angle of the sun's rays. I hope this information helps you learn more about the solstices and equinoxes.