Top 10 Facts You Must Know About the Sun - Tactful Facts

The Sun

The Sun is the star at the center of the Solar System. It is by far the most important source of energy for life on Earth. Its diameter is about 1.39 million kilometers (864,000 miles), or 109 times that of Earth, and its mass is about 330,000 times that of Earth.

1. The Sun accounts for about 99.86% of the total mass of the Solar System.
2. The Sun formed about 4.6 billion years ago from the collapse of part of a giant molecular cloud that consisted mostly of hydrogen and helium and that probably gave birth to many other stars.
3. The solar constant is the amount of power that the Sun deposits per unit area that is directly exposed to sunlight. The solar constant is equal to approximately 1,368 W/m² (watts per square meter) at a distance of one astronomical unit (AU) from the Sun.
4. The Sun's color is white. When the Sun is low in the sky, atmospheric scattering renders the Sun yellow, red, orange, or magenta. Despite its typical whiteness, most people mentally picture the Sun as yellow.
5. The Sun is composed primarily of the chemical elements hydrogen and helium. At this time in the Sun's life, they account for 74.9% and 23.8% of the mass of the Sun in the photosphere, respectively.
6. The core of the Sun extends from the center to about 20–25% of the solar radius. It has a density of up to 150 g/cm³ (about 150 times the density of water) and a temperature of close to 15.7 million kelvin (K).
7. The coolest layer of the Sun is a temperature minimum region extending to about 500 km above the photosphere and has a temperature of about 4,100 K.
8. The first satellites designed for long-term observation of the Sun from interplanetary space were NASA's Pioneers 6, 7, 8, and 9, which were launched between 1959 and 1968. These probes orbited the Sun at a distance similar to that of Earth and made the first detailed measurements of the solar wind and the solar magnetic field.
9. In 1666, Isaac Newton observed the Sun's light using a prism and showed that it is made up of light of many colors.
10. The theory that the Sun is the center around which the planets orbit was first proposed by the ancient Greek Aristarchus of Samos in the 3rd century BC.