The Sun. Motion and constellations

What is the Sun

The Sun, our nearest star, is a gigantic sphere of hot plasma that radiates light and heat in all directions. It is the center of our solar system and provides life and energy to all the planets that orbit it, including Earth.

The Sun is approximately 4.6 billion years old and is estimated to have a lifetime of at least another 5 billion years. Its size is impressive, with a diameter of about 1.4 million kilometers, making it 109 times larger than Earth. Its mass is about 333,000 times that of our planet and it contains more than 99% of the total mass of the solar system.

Studying the Sun is fundamental to understanding how it works and predicting its behavior. Scientists use space and ground-based observatories to study its solar activity, such as sunspots, solar flares and coronal mass ejections, which can affect communications, power grids and navigation systems on Earth.

Chemical composition of the Sun

The Sun is composed mainly of hydrogen (about 74% of its mass) and helium (about 24%), along with traces of heavier elements. At its core, temperatures reach 15 million degrees Celsius and pressures are enormous, allowing nuclear fusion reactions to occur in which hydrogen nuclei combine to form helium, releasing large amounts of energy in the process.

This energy is transported to the surface of the sun through a process known as convection and is then emitted into space in the form of light and electromagnetic radiation at all wavelengths, from gamma rays and X-rays to visible light and even radio waves.

Solar radiation

Solar radiation is essential for life on Earth. It is responsible for photosynthesis in plants, which converts sunlight into chemical energy and provides oxygen to the atmosphere. It is also the main source of heat on our planet, affecting weather patterns and regulating the water cycle.

Studying the Sun is fundamental to understanding how it works and predicting its behavior. Scientists use space and ground-based observatories to study its solar activity, such as sunspots, solar flares and coronal mass ejections, which can affect communications, power grids and navigation systems on Earth.

Motion of the Sun. The solar ecliptic and the zodiac

The movement of the Sun, as seen from Earth, appears to follow a path from east to west due to the Earth’s rotation. In addition, throughout the year, the Sun moves across the sky following a path called the solar ecliptic, due to the Earth’s orbit around the Sun. This annual movement of the Sun causes its position to change daily in relation to the constellations and the horizon. In a broader sense, the Sun also moves in the galaxy, orbiting the center of the Milky Way at a speed of about 220 km/s, completing one revolution in about 225-250 million years.