The Sun and Earth are the primary celestial bodies in our immediate cosmic neighborhood, but their comparison reveals a staggering disparity in size. While Earth is a dense, rocky planet, the Sun is a ball of plasma that governs the entire solar system.
Understanding the difference between our home world and its star requires examining multiple physical properties. This scale is best understood by looking at the linear size, the overall capacity, and the sheer amount of material contained within each body.
Comparing the Diameters
The most direct way to measure how much bigger the Sun is than the Earth is to compare their diameters, or the distance across each body. Earth’s mean diameter is approximately 12,742 kilometers (7,917 miles). The Sun, by contrast, has a diameter of roughly 1,392,000 kilometers (864,000 miles), making it the largest object in our solar system.
The Sun’s diameter is about 109 times greater than that of the Earth. This means that if the Sun were hollow, you could theoretically line up 109 Earths side-by-side across its face. This linear comparison establishes the baseline for the immense scale difference.
The Volumetric Difference: How Many Earths Fit Inside
While a 109-times diameter difference seems large, the size difference becomes exponentially more dramatic when comparing total volume, or the three-dimensional space they occupy. Volume increases by the cube of the linear dimension, meaning a body 109 times wider is far more than 109 times larger in capacity.
If you were to hypothetically fill the Sun, it would take approximately 1.3 million Earths to fill it completely. This huge number results from calculating the volume of a sphere, where the radius is cubed. The Sun’s volume is over 1.3 million times larger than Earth’s volume, demonstrating the power of the cubic relationship. This volumetric comparison provides the most vivid illustration of the Sun’s size relative to our planet.
Comparing the Masses
Shifting focus from physical dimension to gravitational content reveals another measure of the Sun’s dominance: its mass. The Sun’s mass is the primary factor that dictates the structure of the solar system and is approximately 330,000 times greater than the Earth’s mass.
This concentration of matter means the Sun accounts for approximately 99.8% of the total mass of the entire solar system. The remaining 0.2% is split among all the planets, moons, asteroids, and comets. This mass difference creates the gravitational force that binds every object, including Earth, into orbit around the Sun.
Making Sense of the Scale: Analogies
Because numbers like 109 and 1.3 million are abstract, using analogies helps to visualize the difference in size between the Sun and Earth. If the Sun were scaled down to the size of a standard basketball, the Earth would be no larger than a tiny grain of sand, or perhaps the head of a sewing pin. Even the largest planet, Jupiter, would be only the size of a golf ball in this comparison.
Considering the volumetric difference, if a single Earth were represented by a small shot glass, then the Sun would be equivalent to a massive, multi-story water tank. This tank could hold 1.3 million of those shot glasses. The gravitational dominance is harder to visualize but can be thought of as a single object outweighing every other moving part in a complex machine combined by a factor of hundreds.