A desert is an ecosystem where annual rainfall is 10 inches or less. Deserts are dry, inhospitable environments. They occupy over one fifth of the earth’s land.
Earth’s motion around the Sun takes place on a slightly elongated orbit that has the shape of an ellipse, with a speed of 30 km per second. The Earth makes a complete revolution in 365.26 days.
This period is called a stellar year. The Earth’s axis is inclined constantly to the orbital plane, on which it encircles the Sun at an angle of 66.5 ‘. At the Earth moves around the sun axis does not change its position.
Every year, on June 21, there is the summer solstice, which marks both the longest day of the year and earlysummer are astronomical. This occurs in the northern hemisphere, while in the southern hemisphere winter solstice takes place.
On this day, astronomical longitude of the Sun reaches 90 degrees, the moment when the Sun enters the sign of Cancer, at 2:29 p.m..
It is known that the Earth makes two types of movements, so that annually revolution around the Sun, and the allowance for rotation, which axis is in terrestrial poles.
For those of my friends who have missed the first parts. I am providing the links for your reference.