Venus and Earth are often referred to as sister planets because they are the two largest terrestrial worlds in our solar system, sharing striking similarities in their overall structure and composition. This resemblance naturally sparks curiosity about their exact scale, leading to the question of how many Earths would fit inside Venus. The answer to this dimensional puzzle is a fractional value that highlights a subtle yet significant difference in their volumes. Examining their precise measurements reveals that Venus is slightly insufficient to contain the Earth.
The Critical Size Difference: Why One Earth Cannot Fit
Venus is a close match for Earth, yet it is definitively the smaller of the two planets. The quantitative answer to how many Earths can fit inside Venus is approximately 0.86. This means Venus has only about 86% of Earth’s volume, making it impossible for a single Earth to be contained within it.
This volume difference stems from a small variation in radius, which is magnified by the geometric formula for volume. Since the volume of a sphere is proportional to the cube of its radius, even a minor change in the linear measurement creates a significant disparity in total space. Because Venus is roughly 95% the diameter of Earth, the cubic relationship ensures that its interior space is measurably less than Earth’s.
The Physical Stats: Comparing Planetary Dimensions and Mass
The specific measurements confirm that Venus falls short of Earth’s dimensions across the board. Earth’s equatorial diameter is approximately 12,756 kilometers, while Venus’s diameter is about 12,104 kilometers. This difference of over 650 kilometers is what accounts for the missing 14% of volume.
Beyond size, the planets also differ in their bulk properties, particularly mass and density. Venus has a mass of about 4.87 x 10²⁴ kilograms, which is only about 81.5% of Earth’s mass. This means that Earth is significantly heavier than its sister planet.
The difference in mass combined with the slight difference in volume results in a small but measurable difference in density. Earth has an average density of approximately 5.52 grams per cubic centimeter, while Venus measures slightly lower at about 5.24 grams per cubic centimeter. These figures suggest that while both planets share a similar rocky composition with metal cores, Earth is slightly more compressed or contains a slightly larger proportion of denser materials in its interior.