 billion years ago. At the center of that huge cloud, some of the material started to build up into a ball. Once this ball got big enough, reactions inside it caused that ball to shine.
At that point, the Sun blew away all the rest of the cloud from itself, and the planets formed from the rest of this cloud.
At its core, or very center, hydrogen atoms are collided together to form helium. This process is called nuclear fusion. These helium atoms then travel from the core to the surface of the sun, called the photosphere, where they release their energy. Helium atoms can take thousands of years to reach the Sun's surface because other atoms get in their way.
If the Sun is viewed through a very special telescope, dark areas known as sunspots can be seen. These areas are caused by the sun's magnetic field. The sunspots only look dark because the rest of the Sun is very bright.
This is a cycle of 11 years, and every 11 years, there are more sunspots on the Sun than in the past or future years. Between these 11 years, sunspots may decrease in number. This cycle has been around since about the 1700s; before that was the Maunder Minimum, a few hundred years where there were very few sunspots. Astronomers don't know what caused this.
Some space telescopes, like the ones that orbit the sun have seen huge arches that extend from the sun. These are called solar prominences. Solar prominences come in many different shapes and sizes; some of them are so large that the Earth could fit inside of them, and there are a few shaped like hands!
Sometimes, the Sun "disappears" from the sky, and all that people see is a black but shining ball. This is because the Moon has moved right in front of the Sun and blocks almost all of its light. These happen almost every year, and very similar solar eclipses happen every 18 years, 11.3 days; a period called the Saros.
Scientists called astrophysicists say our Sun is a main-sequence star in the middle of its life. In about another 4-5 billion years, they think it will get bigger and become a red giant star. The sun would be up to 250 times its current size, as big as 1.4 AU.
Earth's fate is still a bit of a mystery. Previous calculations show that Earth could escape to a higher orbit. This due to the solar wind, which drops 30% of the sun's mass. But a newer study shows that Earth would possibly vanish itself. This would happen while the sun continues to get bigger due to the tidal forces. However, the sun will lose mass.
Anyway, Earth's ocean and air would have long since worn out. This is even though the sun is still in its main sequence stage. After the Sun reaches a point where it can no longer get bigger, it will literally explode. But not like a supernova. Rather it will expand rapidly and lose its layers, forming a planetary nebula. Eventually the sun will shrink into a white dwarf. Then, over several hundred billion or even a trillion years, the sun would fade into a black dwarf.
Topics of Interest
The Sun is the star at the center of the Solar System. The Sun has a diameter of about 1,392,000 kilometres (865,000 mi) (about 109 Earths), and by itself accounts for about 99.86% of the Solar System's mass; the remainder consists of the planets (including Earth), asteroids, meteoroids, comets, and dust in orbit. About three-fourths of the Sun's mass consists of hydrogen, most of the rest is helium. Less than 2% consists of other elements, including iron, oxygen, carbon, neon, and others.
The mean distance of the Sun from the Earth is approximately 149.6 million kilometers (1 AU), though this varies as the Earth moves from perihelion in January to aphelion in July. At this average distance, light travels from the Sun to the earth in about 8 minutes 19 seconds. The energy from this sunlight supports almost all life on Earth via photosynthesis, and drives the Earth's climate and weather. The enormous impact of the Sun on the Earth has been recognized since pre-historic times, and the Sun has been regarded by some cultures as a deity. An accurate scientific understanding of the Sun developed slowly, 