The solar system
The known Universe contains about 100,000 million galaxies. In one of them is the solar system that is named by one of its stars, the Sun. The gravitational force causes nine planets to move in their orbit, which are distinguished between interior and exterior. Among the first is Earth, the only planet we know on which life has developed. The existence of an atmosphere under certain conditions and the abundance of liquid water are essential for this to be possible.
The universe
The Universe is an unimaginable volume of space and is made up of all the galaxies that exist. Scientific studies only have evidence of a visible Universe, although there could be other universes that we do not see or that ours extended without limits.
Astronomers have not always agreed on the origin of the Universe. The best known theories throughout history have been:
Theory of steady state. The Universe is in continuous creation. When stars and galaxies die, they are replaced by others that arise from nowhere. This theory is absolutely ruled out.
Big Bang Theory. The Universe began after a huge explosion 17,000 million years ago. Matter and energy were compressed into a gigantic mass, known as the "cosmic egg." This mass exploded and galaxies were created from its pieces.
Theory of the cyclic or oscillating universe. A phase of expansion is followed by another phase of concentration. Every 100,000 million years, galaxies unite, collapse and cause a huge explosion.
The solar system
Our solar system consists of 71 stars: the Sun, nine planets that revolve around it and 61 satellites. One of these stars is the Earth, our house.
Although the volume of the solar system seems completely empty, in all that space is the interplanetary medium. This includes several forms of energy and consists of at least two materials: interplanetary dust and interplanetary gas. The interplanetary dust is formed by solid microscopic particles. For its part, interplanetary gas is a faint flow of gas and charged particles that flow from the Sun and are called solar wind.
The planets
The planets are celestial bodies, opaque, that only shine by the light reflected by the Sun, around which they describe their orbit with a proper and periodic movement. Our solar system consists of nine planets, although in 1972 data were provided on the existence of a tenth, but it has not been confirmed.
The planets are divided into interiors and exteriors. They have names of Greek gods and are the following:
Mercury. It takes the same time to walk around the Sun as to do it on itself. One day and one year are the same.
Venus. It is the brightest body in the sky. It is surrounded by acid clouds and an atmosphere of carbon dioxide.
The earth. The only planet in the solar system that meets the necessary conditions for animal and plant life.
Mars. Its red color is due to the iron oxide minerals on the surface.
Jupiter. It is the largest in the solar system. A day in it lasts only 10 hours. Around it rotate 16 satellites.
Saturn. The rings that surround it are rocks that revolve around it. Attract 18 satellites.
Uranus. Its axis of rotation is almost parallel to its orbit. Its existence was not known until 1781.
Neptune. It was discovered in 1846 by means of mathematical calculations that determined its location.
Pluto. It is the smallest of the planets and is located 6,000 million kilometers from the Sun. It was discovered in 1930.
The earth
Earth is the third planet closest to the Sun, the fifth in size and the only one with oxygen and water in abundance. The nearest galaxy to us is that of Andromeda, two million light years away. Surely, it formed from a melt at high temperature and surrounded by a gas layer.
Until a few centuries ago, scientists believed that the Earth was motionless and fixed in the center of the Universe. However, our planet is in orbit around the Sun at a speed of 30 km per second and turns on its own axis once every 24 hours.
THE DATA OF THE EARTH
Age 4.6 billion years
Mass 5,854 million billion tons
Volume 1,083,218,915,000 km3
Distance to the Sun 150 million km
Rotation period 23 hours, 56 minutes, 4 seconds
Orbital period around the Sun 365 days, 6 hours, 9 minutes, 9.5 seconds
Today, Earth can be studied in detail thanks to the help of spacecraft. However, until the 18th century, no complete maps of the planet were available. The images of the Earth taken from space are very important in different fields of science. One of the most notable examples is the invaluable help they suppose in the weather forecast and, especially, in the monitoring of storms.
Rotation movement: succession of days and nights
Countries have different time zones because the Earth is spherical and the Sun does not illuminate all continents equally. The rotation movement explains why different places in the world have different times, as well as areas where it is daytime when in others it is nighttime.
The movement of rotation of the Earth is produced by the confrontation of the electromagnetic waves of the Earth with the electromagnetic waves of the same pole of the Sun. Both produce an action or repulsion effect that is the cause of the rotation or movement of rotation of the bodies They have gravity.
The other bodies of the solar system also rotate, although not all take the same time to do so. Venus uses 243 days, while Pluto, the planet furthest from the Sun, does so in 7 days. The fastest is Jupiter that only takes 10 hours.
In some countries with great distances between its eastern and western parts, different times are indicated for different areas (Russia, Australia, United States and even Spain, which has one hour less in the Canary Islands).
The Earth's rotation movement occurs from West to East. Therefore, we see the Sun appear in the East and hide in the West. Although, in reality, it is the Earth that turns to that side.
the seasons
The Earth does not remain fixed while rotating on itself. Our planet makes a complete turn every 365 days, 5 hours and 49 minutes, in a movement known as translation.
The imaginary axis of rotation of the Earth is a bit tilted. For this reason, the sun's rays reach the earth's surface with a different inclination.
The succession of the four seasons (spring, summer, autumn and winter) is related to the movement of the Earth's movement around the Sun and the inclination of the Earth's axis.
When the sun's rays fall obliquely over the southern hemisphere, the weather is cold and the days are shorter: it is what we know as winter. At the same time, the northern hemisphere receives more sunlight, the days are warmer and longer and therefore it is summer. Whenever it is summer in the southern hemisphere, in the north it is winter, and vice versa.
The Moon and its phases
This satellite is the companion of the Earth in space and, once a month, gives a complete tour of our planet. Astronomers have exposed several theories to explain their origin. The most popular says that a body the size of Mars impacted the Earth and threw a lot of matter into space. All those pieces of rock came together to form the Moon.
THE DATA OF THE MOON
Age 4.6 billion years
Diameter 3,476 km
Average distance from Earth 384,400 km
Time spent orbiting the Earth 27.3 days
Surface temperature -155 ° C to 105 ° C
In its orbit around the Earth, the Moon receives sunlight and a variable part of its illuminated face is visible. These different visions are called phases of the Moon:
New moon or new moon.
Growing room
Full moon or full moon.
Waning quarter.
THE ECLIPSES
An eclipse is a temporary concealment of a star, or of the light that it emits caused by the interposition of another celestial body. The eclipse can be total (if the star is completely covered) or partial (if only part of it is covered).
Eclipse of the Sun. It occurs when the Moon is located between the Sun and the Earth and the sunlight hides us.
Lunar eclipse. It occurs when sunlight does not reach the Moon because the Earth is between the Sun and the Moon.
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