Gravity Across the Solar System: What Would You Weigh on Other Planets?

Understanding Planetary Gravity

Gravity depends on two factors: mass and radius. A more massive object has stronger gravity, but a larger radius means you are farther from the center of mass, reducing surface gravity. This is why Saturn, despite being 95 times more massive than Earth, has surface gravity only slightly higher than our planet.

Weight on Every Planet

Here is what a 150-pound (68 kg) person would weigh on each planet:

The Moon and Major Moons

Our Moon has only 16.6% of Earth's gravity (1.62 m/s²). This is why Apollo astronauts could bounce around despite heavy spacesuits. A 150-pound person weighs just 25 pounds on the Moon.

Other notable moons:

• Titan (Saturn): 0.14g - You could fly with artificial wings
• Europa (Jupiter): 0.13g - Ice skating would be incredible
• Ganymede (Jupiter): 0.15g - Largest moon in solar system
• Io (Jupiter): 0.18g - Most volcanically active body

The Sun and Extreme Gravity

The Sun's surface gravity is 28 times Earth's (274 m/s²). A 150-pound person would weigh 4,200 pounds—equivalent to a car. Of course, you would vaporize long before experiencing this gravity.

Neutron stars have surface gravity billions of times stronger than Earth. A sugar cube of neutron star material would weigh as much as Mount Everest.

Why Mars and Mercury Have the Same Gravity

Despite Mercury being much smaller, it has the same surface gravity as Mars (0.38g). Mercury is extremely dense, with a large iron core making up 85% of its radius. Mars is much larger but less dense, so the surface gravity ends up equal.

Low Gravity Effects on Humans

Extended time in reduced gravity causes:

• Muscle atrophy: Muscles weaken without resistance
• Bone density loss: 1-2% per month in microgravity
• Fluid redistribution: Face puffiness, leg thinning
• Vision changes: Increased intracranial pressure

This is why astronauts on the ISS exercise 2+ hours daily. Future Mars colonists would need similar routines, even with Mars' 38% gravity.

Gas Giants: No Surface to Stand On

Jupiter, Saturn, Uranus, and Neptune have no solid surface. The "surface gravity" values are measured at the level where atmospheric pressure equals Earth's sea level. If you could somehow float there, you would experience that gravity—but you would sink into ever-denser gas and liquid layers below.

Calculating Gravity

Surface gravity can be calculated with:

g = GM/r²

Where:

• G = gravitational constant (6.674 × 10⁻¹¹ N⋅m²/kg²)
• M = planet mass
• r = planet radius

Use our planetary gravity comparison tool to explore these values interactively.

Key Takeaways

1. Jupiter has the strongest gravity of any planet (2.53g)
2. Mars and Mercury have identical surface gravity (0.38g)
3. Saturn's low density gives it near-Earth gravity despite huge mass
4. Extended low gravity causes significant health effects
5. The Sun's gravity would crush a human (28g)