Among the most striking comparisons in our solar system is that between our home planet, Earth, and the colossal Sun. A common question arises: how many Earths could truly fit inside it?
The Astonishing Number: A Direct Answer
The Sun’s immense size means it can contain a staggering number of Earths. Approximately 1.3 million Earths could fit inside the Sun’s total volume. This figure assumes the Earths could be compressed or melted to eliminate any empty space between them. When considering their diameters, the Sun is about 109 times wider than Earth, meaning 109 Earths could line up side-by-side across its face.
Understanding the Scale: Diameter Versus Volume
The difference between these two numbers, 109 and 1.3 million, highlights an important distinction: comparing diameters versus comparing volumes. Measuring by diameter means imagining Earths laid out in a straight line across the Sun’s middle. This comparison indicates how many Earths would span the Sun’s width.
Volume, however, refers to the total three-dimensional space an object occupies. When asking how many Earths can “fit inside” the Sun, it usually refers to volume. The much larger number for volume arises because volume scales with the cube of the radius or diameter. While 109 Earths fit across the diameter, 109 multiplied by itself three times (109 x 109 x 109) yields roughly 1.3 million, demonstrating the vast difference in three-dimensional space. This calculation provides the theoretical maximum if Earths could be perfectly packed without gaps.
Putting It in Perspective: Visualizing the Immensity
To truly grasp the Sun’s magnitude, consider relatable analogies. If Earth were the size of a marble, the Sun would be comparable to a gigantic beach ball. Alternatively, if the Sun were imagined as a soccer ball, Earth would be no larger than the plastic head of a sewing pin, located about 25 yards away.
The Sun also contains the vast majority of matter in our solar system. It accounts for an astonishing 99.86% of the solar system’s total mass. Even if all the planets in our solar system were combined, their collective mass would still be dwarfed by the Sun.
What Makes the Sun So Vast?
The Sun’s immense size stems from its fundamental nature as a star. It is a massive, nearly perfect sphere composed primarily of hot plasma. The Sun’s composition is mainly hydrogen, accounting for about 70% to 75% of its mass, and helium, making up roughly 23% to 28%.
This gaseous composition, held together by its own powerful gravity, creates conditions within its core that power nuclear fusion. In this process, hydrogen atoms combine to form helium, releasing an enormous amount of energy that radiates outward. This continuous energy generation and its substantial mass allow the Sun to maintain its enormous size and luminosity.