What is the sun?
The Sun is a star: It is a massive, glowing sphere of hot gas, primarily composed of hydrogen (about 75%) and helium (about 24%). The Sun's core is where nuclear fusion occurs, producing the energy and light we receive.
The Sun is huge: It makes up about 99.86% of the total mass of the entire solar system. It has a diameter of about 1.4 million kilometers (870,000 miles), which is about 109 times the diameter of Earth.
It takes sunlight around 8 minutes to reach Earth: The Sun is about 93 million miles (150 million kilometers) away from Earth, and the light it produces travels at 186,282 miles per second (300,000 kilometers per second).
The Sun's energy output is enormous: Every second, the Sun releases about 3.8 million trillion megawatts of energy. This energy comes from the process of nuclear fusion, where hydrogen atoms combine to form helium and release energy.
The Sun has an 11-year solar cycle: The Sun’s magnetic field goes through a cycle of about 11 years, during which the number of sunspots fluctuates, and solar activity (like solar flares and coronal mass ejections) increases and decreases.
The Sun is middle-aged: At around 4.6 billion years old, the Sun is considered to be in the middle of its life cycle. It has about 5 billion more years before it enters the red giant phase and eventually becomes a white dwarf.
The Sun is not a solid object: Unlike Earth, the Sun is composed of plasma, a superheated, electrically charged gas. The Sun's outer layers (like the photosphere and corona) are constantly in motion.
Solar wind: The Sun emits a continuous stream of charged particles known as the solar wind. This wind can affect space weather and even disrupt satellites and communications on Earth during solar storms.
Sunspots are cooler areas: Sunspots are temporary phenomena on the Sun's surface that appear darker because they are cooler than the surrounding areas. They are caused by magnetic activity and can last from days to months.
The Sun will eventually become a red giant: In about 5 billion years, the Sun will exhaust its hydrogen fuel in the core, causing it to expand into a red giant. It will engulf the inner planets, possibly including Earth, before eventually shedding its outer layers and becoming a white dwarf.