Radius, diameter, and circumference The sun's average radius is 432,450 miles (696,000 kilometers), resulting in a diameter of around 864,938 miles (1.392 million km). 109 Earths might be lined up across the face of the sun. The circumference of the sun is approximately 2,713,406 miles (4,366,813 km). It takes the sun about 365 days to orbit the center of the earth.
The surface area of the sun is how much space it covers at the surface. This space is called the solar surface. The solar surface is about 1.5 million miles² (3.7 million km²) or about half the size of the planet Earth.
The sun is a star that uses energy to heat its outer atmosphere, or corona. The corona consists of plasma that reaches temperatures as high as 1 million degrees Fahrenheit (500,000 degrees Celsius). The solar wind is a stream of charged particles that flows from the sun out into space at more than 500 miles per hour (800 km/hr).
The sun is responsible for all natural radio transmissions and most radar returns on Earth. During a total solar eclipse, when the moon blocks out part of the sun, any technology dependent on sunlight for operation will cease to function. For this reason, astronauts aboard the Apollo spacecraft wore special sunglasses during their lunar walks to protect them from the sun's intense light.
You may Google it up; the sun's angular diameter is 0.5 deg. It's also quite simple to compute. In the diagram below, D represents the Sun's real diameter (1.392 x 106km) and d indicates the distance between the Earth and the Sun (149,598,261 km). The Sun's radius (r) will be half of D (r = D/2). Therefore, the angle θ formed by the tangent to the solar surface at any point and the vertical axis is r/d.
Since the angular diameter of the Sun is constant, it can be used to find out how much its disk covers at any time. For example, if we know that the Sun's disk covers one quarter of the sky during a sunset or sunrise, then we can calculate the length of a straight line that crosses the two events and ends up on the ground: the height of the line above sea level is 2r sin θ, where θ is the angular diameter of the Sun at its highest point in the sky. Since the length of this line is equal to the distance from the center of the Earth to the center of the Sun, we can estimate that the height of the Sun above the Earth's surface is about 507m.
The angular diameter of the Sun varies over time. It is actually decreasing due to evolution of the Sun itself and expansion of its atmosphere. However, since 1610 when Galileo first measured it with his telescope, it has been exactly constant within 0.5%.
Circumference of the sun is 4.379 million kilometers. That's about 3% smaller than the solar system's largest planet, Jupiter.
The sun is just a star like many other stars in the galaxy. It burns hot enough to be visible from Earth and it has an influence on our environment that reaches well beyond our star system. The gravity of the sun pulls on Earth's atmosphere and this causes weather events such as hurricanes, tornados, and monsoons. The radiation from the sun plays a role in the evolution of life on Earth by helping to create organic molecules that become plants and animals. Humans also use telescopes to look at parts of the sun's surface with different compositions to study how it evolved over time.
The diameter of the sun is 940,000 km, or 5% larger than its estimated average radius. This means that the center of the sun is almost completely empty, except for some small quantities of hydrogen and helium.
The sun is a giant nuclear reactor approximately 109 times more massive than the earth. The core of the sun may be as large as 28 miles across, while the core of our planet is only 880 miles wide.