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| Our Sun A Yellow Dwarf/Photo Astronomy for armatures |
Our Sun is not unique in the universe. It is a common middle-sized yellow star which scientists have named Sol. This is why our system of planets is called the Solar System. There are trillions of other stars in the Universe just like it. Many of these stars have their own systems of planets, moons, asteroids, and comets.
The Sun was born in a vast cloud of gas and dust around 5 billion years ago. Indeed these vast nebulae are the birth places of all stars. Over a period of many millions of years, this gas and dust began to fall into a common center under the force of its own gravity.
At the center, an ever growing body of mass was forming. As matter falls inward, it generates a tremendous amount of heat and pressure. As it grew, the baby Sun became hotter and hotter. Eventually when it reached a temperature of around 1 million degrees, its core ignited, causing it to begin nuclear fusion
When this happened, the Sun began producing its own light, heat, and energy.
Nuclear fusion is how stars produce their light, heat, and energy. Through this process, they “burn” a fuel known as hydrogen. The result is that they create another type of matter known as helium. However, stars do not burn in the same way that a fire does, because stars are not on fire.
Heat rises, while cooler gas falls. Have you ever noticed that your basement is always much cooler than upstairs. The same laws of physics apply within stars. Because heat rises, while cooler gases fall, the gas within stars is constantly rising and falling. This creates massive streams of circular motion within the star. This is called convection.
As the gases near the core of the Sun are heated, they begin to rise towards the surface. As they do so, they cool somewhat. Eventually, they become cool enough that they begin to sink back down towards the core. It can take an atom millions of years to complete one complete cycle around a convection stream.
On a side note in a recent poll conducted by a leading astronomy magazine found that 55% of adults in the United States don't know that the sun is a typical star, the Sun is known as a yellow dwarf star. This group of stars are relatively small, containing between 80% and 100% the mass of the sun. So the Sun is at the higher end of this group. The official designation is as a G V star.
We will continue the current topic of exploring our sun in the next post, hope you enjoyed today's post and learnt something new.
