Solar system

The sun is our star

The sun is our star

He Sun It is the closest star to Earth and the largest star in the Solar System. It is part of the galaxy we call Milky Way.

Stars are the only bodies in the Universe that emit light. The Sun, that nearby star, is located about 150 million kilometers from Earth and is by far the brightest celestial object we can see.

The Sun contains more than 99.8% of all matter in the Solar System. In fact, "almost everything" the Solar System is in the Sun. It exerts a strong gravitational attraction on the planets and spins them around. Together with asteroids, meteoroids, comets and dust form the Solar system.

Here are some Sun data compared to Earth:

Basic informationSunThe earth
Size: equatorial radius695,000 km.6,378 km.
Period of rotation on the axisfrom 25 to 36 days23.93 hours
Mass compared to Earth332.8301
Average surface temperature6000 º C15 º C
Surface gravity in the photosphere 274 m / s29.78 m / s2

The entire Solar System, including the Sun, revolves around the center of the Milky Way, our galaxy, located about 25,800 light years away. Go around completely every 225 million years. In our times it moves towards the constellation of Hercules at 19 km / s.

Our particular star formed about 4.6 billion years ago and has fuel for another 5,000 million more. Then, it will start to get bigger and bigger, until it becomes a red giant star. Finally, it will sink under its own weight and become a white dwarf, which can take up to a trillion years to cool.

How do you study the sun?

Currently the Sun is studied from some satellites, such as the Heliospheric and Solar Observatory (SOHO), equipped with instruments that allow us to appreciate aspects that, until now, had not been possible to investigate.

In addition to observation with conventional telescopes, the following are used:

• he coronograph, which analyzes the solar corona
• he extreme ultraviolet telescope, an instrument capable of detecting the magnetic field
• the radio telescopes They can detect various types of radiation that are imperceptible to the human eye.

On August 12, 2018, NASA launched the space Parker probe, destined to investigate the crown of the Sun, its magnetic field and the solar wind. It will orbit 6.2 million kilometers from the solar surface, the photosphere.

How is solar energy produced?

The Sun is an immense sphere of plasma, a little bigger and hotter than a medium star. It produces a large amount of electromagnetic energy through nuclear fusion processes.

74% of the solar matter is Hydrogen (H), another 24% is Helium (He) and the remaining 2% is distributed among various chemical elements among which Oxygen (O), Iron (Fe) and Nickel stand out (Neither). These gases have a convective movement that transports heat and energy outward. This dynamo effect generates a powerful magnetic field.

The period of rotation of the solar surface goes from 25 days in the equator to 36 days near the poles. Further inside it seems that everything revolves every 27 days. This different rotation according to latitude causes the magnetic field lines to curl over time, causing the formation of spots and the spectacular solar protuberances.

The Sun maintains life and climate on Earth

Our main source of energy is the Sun, from which we receive radiation, especially in the form of light and heat. Vegetables, through photosynthesis, take advantage of sunlight to produce their food that, at the same time, feed all living things. Your energy too determine the weather from the earth.

Most of the energy sources we use also come from the Sun, even indirectly. For example, fossil fuels conserve underground the solar energy captured by vegetables and algae millions of years ago through photosynthesis. Hydropower uses the weight of the water that fell from the clouds because the Sun evaporated it. The wind takes advantage of the winds caused by temperature differences in the atmosphere. And the energy captured by solar panels ... where does it come from?

As our planet rotates on its axis once every 24 hours, it seems that the Sun rises in the east, moves through the sky and hides in the west. Its presence or absence makes it day or night.

Finally some tips: the sun is dangerous If no precautions are taken. Excessive sun exposure can cause from sunstroke to skin cancer. On the other hand, looking directly at the Sun can cause eye injuries, including blindness. To observe it, for example, during a solar eclipse, you have to use special filters or crystals. Sunglasses and home remedies do not work. If binoculars or telescopes are used, sunscreens should be placed in the front and never in the eyepiece.

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How did the solar system form?Structure and composition of the Sun