Neptune vs Earth: Comparison, Size, Mass, Gravity, Similarities and Differences

Neptune vs Earth: Comparison, Size, Mass, Gravity, Similarities and Differences

Neptune vs Earth

The cosmos is a treasure trove of celestial wonders, each with its unique attributes. In this comparison, we delve into the intriguing differences between Neptune and Earth, shedding light on their distinctive characteristics that set them apart in our cosmic neighborhood.

Neptune Compared to Earth

Neptune and Earth are two planets in our solar system, each with distinct characteristics and properties. Comparing them provides insights into the diversity of planetary bodies within our cosmic neighborhood.

Neptune and Earth Similarities

  1. Composition:
    • Both Neptune and Earth are predominantly composed of hydrogen and helium. However, Neptune has a larger proportion of ices, including water, methane, and ammonia, contributing to its classification as an ice giant.
  2. Magnetic Fields:
    • Both planets have magnetic fields. Earth's magnetic field is primarily generated by its iron-nickel core, while Neptune's magnetic field is generated by a combination of its rocky core and icy mantle. Neptune's magnetic field is tilted relative to its rotation axis, similar to Earth's.
  3. Rotation Direction:
    • Both Neptune and Earth rotate counterclockwise on their axes. However, Neptune has a unique feature—a relatively fast and retrograde rotation. Its equatorial rotation speed is higher than that of Earth.
  4. Natural Satellites:
    • Both planets have moons (natural satellites). Earth has one large moon, while Neptune has 14 known moons. Triton, Neptune's largest moon, is notable for its retrograde orbit.

Neptune and Earth Differences

  1. Atmosphere:
    • Earth's atmosphere is primarily nitrogen and oxygen, conducive to life as we know it. Neptune's atmosphere, on the other hand, is primarily composed of hydrogen and helium, with traces of methane. Its atmosphere gives Neptune its distinct blue color.
  2. Surface Conditions:
    • Earth has a solid surface with diverse landscapes, including continents and oceans. Neptune, being an ice giant, lacks a solid surface. Its outer layers consist of a thick atmosphere and an interior composed of icy and rocky materials.
  3. Temperature:
    • Earth has a diverse climate with temperatures suitable for liquid water, essential for life. Neptune, being much farther from the Sun, is colder, with an average temperature of about -214 degrees Celsius (-353 degrees Fahrenheit).
  4. Ring Systems:
    • While Earth does not have a ring system, Neptune is known for its faint and complex ring system. These rings are primarily composed of dust particles and rocky debris.

Neptune and Earth Size Comparison

Neptune and Earth exhibit notable differences in size:

  • Neptune:
    • Diameter: Approximately 49,244 kilometers (30,598 miles)
    • Volume: About 57 times that of Earth
    • Radius: Around 24,622 kilometers (15,299 miles)
  • Earth:
    • Diameter: Approximately 12,742 kilometers (7,918 miles)
    • Volume: Smaller compared to Neptune
    • Radius: Around 6,371 kilometers (3,959 miles)

Neptune and Earth Mass Comparison

  • Neptune:
    • Mass: Approximately 17 times that of Earth
  • Earth:
    • Mass: Smaller compared to Neptune

Neptune and Earth Gravity Comparison

  • Neptune:
    • Gravity: Approximately 11.15 m/s² (equatorial)
  • Earth:
    • Gravity: Approximately 9.81 m/s²

Neptune and Earth Side by Side

If placed side by side, Neptune would appear significantly larger than Earth due to its greater diameter and volume. The stark contrast between Earth's solid surface and Neptune's gaseous and featureless exterior would be evident. Earth's diverse ecosystems, including continents and oceans, would contrast with Neptune's dynamic and turbulent atmosphere.

Neptune and Earth

Here's a brief overview of the main differences between Neptune and Earth:


  • Much larger in diameter than Earth.
  • Composed mainly of hydrogen, helium, and methane.
  • Atmosphere is rich in hydrogen, helium, and methane, giving it a blue color.
  • Extreme weather patterns with powerful storms and supersonic winds.
  • Lacks a solid surface; consists of gases and icy compounds.
  • Orbits far from the Sun, resulting in extremely cold temperatures.


  • Smaller in diameter compared to Neptune.
  • Composition includes nitrogen, oxygen, water vapor, and other gases.
  • Atmosphere is rich in oxygen, suitable for supporting life.
  • Moderate weather patterns; diverse climates and ecosystems.
  • Solid surface with continents, oceans, mountains, and valleys.
  • Orbits in the habitable zone, maintaining temperate conditions and liquid water.

In essence, Neptune's icy and gaseous nature, along with its distant orbit, distinguishes it from Earth's vibrant biosphere, temperate climate, and solid surface.

Earth vs Neptune

Here's a detailed specification table comparing the Neptune and Earth:

Specification Neptune Earth
Diameter 49,244 km 12,742 km
Mass 1.024 x 10^26 kg (17 Earth masses) 5.972 x 10^24 kg
Composition Hydrogen, helium, methane Nitrogen, oxygen, water vapor
Atmosphere Hydrogen, helium, methane Nitrogen (78%), oxygen (21%)
Atmospheric Pressure 1 bar 1 bar
Atmospheric Color Blue due to methane absorption Blue due to Rayleigh scattering
Surface Lacks a solid surface; icy and gaseous Solid surface with land and water
Orbital Distance from Sun Approximately 4.5 billion km (30.05 AU) Approximately 149.6 million km
Orbital Period About 165 years About 365.25 days
Average Surface Temperature Approximately -353°F (-214°C) Approximately 59°F (15°C)
Liquid Water Unknown if subsurface oceans exist Abundant in oceans, lakes, rivers
Moons 14 moons, including Triton 1 moon (The Moon)


Neptune vs Earth Size

Neptune and Earth differ significantly in terms of size. Neptune's diameter is approximately 49,244 kilometers, making it nearly four times larger than Earth. This immense size earns Neptune the title of the solar system's fourth-largest planet. In contrast, Earth's diameter measures around 12,742 kilometers. This size disparity is visible even in telescopic observations, where Neptune appears as a distinct blue disc while Earth's familiar continents and oceans can be discerned.

Neptune vs Earth Temperature

Temperature diverges dramatically between Neptune and Earth due to their varying distances from the Sun and atmospheric compositions. Neptune's average surface temperature hovers around a bone-chilling -353°F (-214°C), making it one of the coldest objects in our solar system. This frigidity is attributed to Neptune's distant orbit and limited solar energy absorption. Earth, on the other hand, maintains a much milder average temperature of approximately 59°F (15°C), allowing for the existence of liquid water and a habitable climate.

Neptune vs Earth Mass

Neptune and Earth possess distinct masses that significantly influence their gravitational interactions and overall characteristics. Neptune's mass is approximately 1.024 x 10^26 kilograms, equivalent to about 17 times the mass of Earth. This substantial mass contributes to Neptune's immense size and strong gravitational pull. Earth's mass, comparatively smaller, is approximately 5.972 x 10^24 kilograms, allowing for a balanced gravitational force that sustains life, retains an atmosphere, and shapes the planet's geological features.

Neptune vs Earth Atmosphere

The atmospheres of Neptune and Earth set them apart with their unique compositions and behaviors. Neptune's atmosphere primarily consists of hydrogen (80%) and helium (19%), along with trace amounts of methane that lend its distinctive blue color. This atmosphere creates a dynamic environment with fast winds and powerful storms, such as the Great Dark Spot. Earth's atmosphere, dominated by nitrogen (78%) and oxygen (21%), facilitates the existence of life through its moderate temperatures and the vital oxygen it provides. Earth's atmosphere also enables weather patterns, climate regulation, and protection from harmful solar radiation.


Neptune and Earth exhibit remarkable differences in terms of size and composition. Neptune, classified as an ice giant, boasts a diameter approximately four times that of Earth, making it one of the largest planets in our solar system. Its composition primarily comprises hydrogen, helium, and traces of methane. In contrast, Earth, often referred to as the "Blue Planet," has a diverse composition of nitrogen, oxygen, water vapor, and other gases that sustain life.

Surface and Hydrosphere

Unlike Earth's solid surface, Neptune's surface is mainly composed of a mix of gases and icy compounds. Its lack of a distinct solid surface has led to its categorization as an ice giant. Earth's surface is adorned with continents, oceans, mountains, valleys, and diverse ecosystems. The presence of liquid water on Earth's surface is a defining feature that supports a wide range of life forms and shapes the planet's climate.

Orbital and Environmental Factors

Neptune orbits much farther from the Sun compared to Earth, resulting in its extremely cold temperatures. Its distance from the Sun leads to lower solar energy absorption, contributing to its icy nature. Earth's position in the habitable zone allows for a temperate climate conducive to the existence of liquid water, making it a fertile ground for biodiversity.


The comparison between Neptune and Earth reveals their contrasting natures within our solar system. Neptune's icy expanse, turbulent atmosphere, and distant orbit stand in stark contrast to Earth's vibrant biosphere, temperate climate, and life-sustaining characteristics. While Neptune's allure lies in its enigmatic beauty, Earth's significance as our home underscores the incredible diversity of worlds that coexist in the cosmos.

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