The Sun's radius, often denoted as "R☉," is the distance from the center of the Sun to its outer edge or surface. The Sun is not a solid object but a massive, hot, and highly compressed ball of gas, primarily hydrogen and helium.
The average or mean radius of the Sun is approximately 696,340 kilometers (about 432,685 miles). Keep in mind that the Sun's outer boundary is not sharply defined, and its structure consists of different layers, including the core, radiative zone, convective zone, and the visible surface known as the photosphere.
The Sun's radius is a fundamental parameter in astronomy and solar physics and is used as a reference point for measuring distances within the solar system and studying the properties and behavior of the Sun.
The average distance from Earth to the Sun is about 149.6 million kilometers (or approximately 93 million miles). This distance is often referred to as an astronomical unit (AU), which is a standard unit of measurement used in astronomy to describe distances within our solar system. An astronomical unit is defined as the average distance between the Earth and the Sun.
It's important to note that the Earth's orbit around the Sun is not a perfect circle but rather an ellipse, so the distance between Earth and the Sun varies slightly throughout the year. The value given here represents the average distance. The closest point in Earth's orbit to the Sun is called perihelion, while the farthest point is called aphelion. Perihelion occurs around early January, and aphelion occurs around early July. At perihelion, Earth is approximately 147.1 million kilometers (about 91.4 million miles) from the Sun, while at aphelion, it is about 152.1 million kilometers (around 94.5 million miles) away.