The Sun is our very own star. It gives us light, energy and warmth and without it, life could not exist on Earth. But what is a star and what kind of star is our Sun?
A star is a huge sphere of very hot, ionised gas. Because of the pressure and temperature in the core of a star, a nuclear reaction takes place that forms helium from hydrogen. This generates enormous amounts of energy, which is slowly carried outward until it finally reaches the surface and radiates out into space in the form of heat, light and other forms of radiation. This journey of energy to the surface can take up to a million years. Our Sun is a quite small and average star in the main sequence. Its surface has temperatures of about 5.500 degrees Celsius, which results in a yellowish light. Hotter stars will appear
A star is a huge sphere of very hot, ionised gas. Because of the pressure and temperature in the core of a star, a nuclear reaction takes place that forms helium from hydrogen. This generates enormous amounts of energy, which is slowly carried outward until it finally reaches the surface and radiates out into space in the form of heat, light and other forms of radiation. This journey of energy to the surface can take up to a million years. Our Sun is a quite small and average star in the main sequence. Its surface has temperatures of about 5.500 degrees Celsius, which results in a yellowish light. Hotter stars will appear
bluish, while cooler stars will seem orange or reddish. With an age of about 4.6 billion years, our Sun is halfway through its lifecycle. The gravity of the Sun had captured all sorts of other material in orbits around it. Besides our Earth and Moon, there are seven other planets with their moons, several dwarf planets, asteroids, meteoroids and comets. They all orbit the Sun in some way and are therefore part of the solar system.
Since the Sun is the closest star and we are so dependant on it, it has been intensely studied. Since 1960, series of space probes and satellites have been launched by NASA and other organisations to collect data about the Sun. Here a few important missions.
Between 1960 and 1968 the Pioneer space probes 5 to 9 (USA) orbited the Sun and studied solar wind, solar flares and the magnetic field. In 1974 and 1975 the Helios 1 and 2 (USA and Germany) passed close to the Sun’s surface. They measured the solar wind and the Sun’s magnetic field. In 1980 the Ulysses (USA and Europe) was the first to orbit the Sun’s poles. In 1991 the Yohkoh (Japan, USA and UK) was launched. This was an Earth orbiting satellite that collected data for ten years. In 1995 the USA and Europe launched SOHO (Solar and Heliospheric Obeservatory) studying the Sun’s interior as well as events on its surface at an orbit of 1.5 million kilometres (930.000 miles) from Earth in the direction of the Sun. Although we know a lot about the Sun already, there is still much more to learn.
Between 1960 and 1968 the Pioneer space probes 5 to 9 (USA) orbited the Sun and studied solar wind, solar flares and the magnetic field. In 1974 and 1975 the Helios 1 and 2 (USA and Germany) passed close to the Sun’s surface. They measured the solar wind and the Sun’s magnetic field. In 1980 the Ulysses (USA and Europe) was the first to orbit the Sun’s poles. In 1991 the Yohkoh (Japan, USA and UK) was launched. This was an Earth orbiting satellite that collected data for ten years. In 1995 the USA and Europe launched SOHO (Solar and Heliospheric Obeservatory) studying the Sun’s interior as well as events on its surface at an orbit of 1.5 million kilometres (930.000 miles) from Earth in the direction of the Sun. Although we know a lot about the Sun already, there is still much more to learn.
Regards from the bush
Miriam
Miriam
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