Helios

The Sun is a yellow dwarf star, a hot ball of glowing gases at the heart of our solar system. Its gravity holds the solar system together, keeping everything – from the biggest planets to the smallest particles of debris – in its orbit.

Sol

In about 5.5 billion years the Sun will run out of hydrogen and begin expanding as it burns helium. It will swap from being a yellow giant to a red giant, expanding beyond the orbit of Mars and vaporizing Earth—including the atoms that make-up you.

Five planets have been known since ancient times — Mercury, Venus, Mars, Jupiter, and Saturn. The first new planet discovered was Uranus. It was discovered by the English astronomer Sir William Herschel in 1781….

4.54 billion years

Scientists estimate that the Solar System is 4.6 billion years old. The oldest known mineral grains on Earth are approximately 4.4 billion years old.

4,500,000,000 years old

By that point, all life on the Earth will be extinct. The most probable fate of the planet is absorption by the Sun in about 7.5 billion years, after the star has entered the red giant phase and expanded beyond the planet’s current orbit.

The sun gets so hot from its nuclear fusion that it glows and emits light, just like how a piece of metal glows red if you heat it up. There are two main forces at work in nuclear fusion: the electromagnetic force and the strong nuclear force.

The Sun warms our seas, stirs our atmosphere, generates our weather patterns, and gives energy to the growing green plants that provide the food and oxygen for life on Earth. We know the Sun through its heat and light, but other, less obvious aspects of the Sun affect Earth and society.

Sunburn is caused by too much exposure to ultraviolet (UV) light. UV light may be from sunlight or artificial sources, such as sunlamps and tanning beds. Melanin is the dark pigment in the skin’s outer layer that gives skin its normal color.

In this way the Sun consumes about 5 billion kilograms (5 million tons) of its nuclear hydrogen fuel every second. Yet the Sun is so large that it has been burning hydrogen at this rate ever since it formed some 5 billion years ago, and it will continue to burn steadily for at least another 4 billion years.

The Sun does not “burn”, like we think of logs in a fire or paper burning. The Sun glows because it is a very big ball of gas, and a process called nuclear fusion is taking place in its core. Hydrogen really doesn’t burn, it fuses, into helium. So no oxygen is required!

The sun releases energy at a mass–energy conversion rate of 4.26 million metric tons per second, which produces the equivalent of 384.6 septillion watts (3.846×1026 W).

Its mass is about 330,000 times that of Earth; it accounts for about 99.86% of the total mass of the Solar System. Roughly three quarters of the Sun’s mass consists of hydrogen (~73%); the rest is mostly helium (~25%), with much smaller quantities of heavier elements, including oxygen, carbon, neon and iron.