The Solar System contains two fundamentally different types of worlds: the small, rocky terrestrial planets and the immense, gaseous outer giants. Earth is a water-rich, terrestrial sphere with a relatively thin atmosphere. Jupiter, the fifth planet from the Sun, is a colossal gas behemoth whose sheer size and composition create an environment alien to our own experience. Comparing these two worlds reveals the astonishing diversity possible within a single stellar system, impacting internal structure, gravitational pull, and the nature of time and weather.
Physical Scale and Structure
The disparity in physical size and mass between Earth and Jupiter is vast. Jupiter’s diameter is approximately 11 times greater than Earth’s; its volume is so vast that over 1,300 Earths could be contained within it. Jupiter weighs roughly 318 times more than Earth, accounting for more than twice the mass of all the other planets in the Solar System combined.
Despite its colossal mass, Jupiter is far less dense than Earth due to its composition. Earth is a terrestrial world made of silicate rock and metals, giving it a density of about 5.5 grams per cubic centimeter. Jupiter is composed primarily of hydrogen and helium, resulting in a low average density of only about 1.3 grams per cubic centimeter.
Earth’s interior is differentiated into a metallic core, a thick mantle, and a crust. Jupiter’s structure is defined by immense pressure, which compresses its hydrogen and helium into exotic states. Below the visible cloud tops lies a region of liquid metallic hydrogen, an electrically conductive fluid. This layer surrounds a dense central region, which scientists believe is a core of rock and ice that may be up to 15 times the mass of Earth.
The difference in mass dictates the gravitational forces on each body. Earth’s gravity accelerates objects at 9.8 meters per second squared, defining a standard “g”. Jupiter’s colossal mass generates a much stronger pull, with gravitational acceleration at the cloud tops about 2.5 times stronger than Earth’s.
Orbital Dynamics and Time
The positions of the planets relative to the Sun introduce profound differences in their environments and timekeeping. Earth orbits at one Astronomical Unit (AU) from the Sun. Jupiter is far more distant, situated at an average of 5.2 AU (approximately 778 million kilometers away). This greater distance means Jupiter receives significantly less solar radiation than Earth, contributing to its extremely cold upper atmosphere.
The time it takes for each planet to complete one orbit, defining a year, varies dramatically. Earth completes its solar circuit in 365 days. Jupiter requires nearly 12 Earth years (11.86 years) to finish a single revolution. The rotation period, which defines the length of a day, is nearly opposite to the orbital period difference.
Earth’s rotation takes nearly 24 hours to complete one turn on its axis. Despite its immense size, Jupiter rotates the fastest of any planet in the Solar System, completing a day in just under 10 hours. Jupiter also has a very small axial tilt of only about 3 degrees. This means the giant planet experiences almost no seasonal variation, unlike Earth’s pronounced seasons caused by its 23.5-degree tilt.
Atmospheric Differences and Weather
The atmospheres of the two planets differ in composition, appearance, and dynamics. Earth’s atmosphere is composed primarily of nitrogen (78%) and oxygen (21%), creating breathable air. Jupiter’s atmosphere is overwhelmingly composed of hydrogen (about 90%) and helium (about 10%), with trace amounts of gases like methane and ammonia.
Because Jupiter lacks a solid surface, its atmosphere gradually grows denser with depth, transitioning into liquid phases under crushing pressure. The average temperature at the 1-bar pressure level (comparable to Earth’s sea level) is frigid, averaging around \(-110^\circ \text{C}\) (\(-166^\circ \text{F}\)). Earth’s average surface temperature, in contrast, is approximately \(15^\circ \text{C}\) (\(59^\circ \text{F}\)).
Jupiter’s appearance is dominated by alternating bands of bright zones and dark belts, driven by powerful jet streams. These atmospheric flows generate winds that can reach speeds of over 539 kilometers per hour (335 miles per hour). This weather system produces the Great Red Spot, a massive anticyclonic storm wider than Earth that has raged for centuries.
Unlike Earth’s hurricanes, which dissipate when they make landfall, Jupiter’s storms have no solid surface to slow them, allowing them to persist. Data from the Juno spacecraft shows that the Great Red Spot extends hundreds of miles deep into the atmosphere, a vertical scale far surpassing any storm on Earth. Earth’s weather, driven by the water cycle, involves smaller, shorter-lived systems constrained by mountains, landmasses, and oceans.