Sun
The Sun is the most prominent feature in our solar system and contains approximately 98% of the total solar system mass. The Sun is about 4.5 billion years old. The turbulent eruptions of energy at the surface are called sun spots.
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Solar energy passes through the chromosphere on its way out from the center of the Sun. As shown in the illustration, faculae and solar flares arise in the chromosphere. Faculae are bright luminous hydrogen clouds which form above regions where sunspots are about to form. Flares are bright filaments of hot gas emerging from sunspot regions. Sunspots are cool regions in the photosphere with a typical temperature of 4,000°C. |
The Sun's surface is called the photosphere and has a temperature of 6,000°C. The sun's core temperature can reach 15 million degrees and a pressure of 340 billion times Earth's air pressure. Four protons or hydrogen nuclei are fused together to form one alpha particle or helium nucleus. The fusion energy and is carried to the surface of the Sun, through convection where it is released as light and heat at the surface. Every second, seven hundred million tons of hydrogen are converted into helium to produce 386 billion billion megawatts.
In addition to heat and light, the Sun also emits charged particles (mostly protons & electrons) known as the solar wind and interstellar dust particles.
- Solar wind propagates throughout the solar system at about 450 km/sec. The solar wind of higher energy particles can have dramatic effects on the Earth ranging from power line surges to radio interference to the beautiful aurora borealis.
- Interstellar dust particles range from 10 -7 centimeters in diameter with a mass of 10 -21 grams to a millimeter (10 -1 centimeter) in diameter with a mass of one milligram (10 -3 gram). The density of the interstellar dust particls is about 2 grams cm-3.
For more information, see about the Sun and planets.