Weight on Other Planets
Your weight changes on every planet because gravity varies. Mass stays constant, but weight (force of gravity) depends on each world's surface gravity. Use Newton's law W = mg to compare how you'd feel across the Solar System.
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Mass is constant everywhere; weight changes with gravity. Jupiter has 2.53× Earth gravity; Moon has 0.17×. Jump height is inversely proportional to gravity. Mars at 38% gravity requires exercise to maintain bone density.
Ready to run the numbers?
Why: Understanding gravitational variation is essential for space mission planning, astronaut health, and designing habitats. Mars colonization requires knowing how 38% gravity affects bone density and daily life.
How: Weight = mass × local gravity. Mass is constant; gravity varies by planet. Use g = GM/r² for surface gravity. NASA JPL provides official planetary data.
Run the calculator when you are ready.
⚖️ Enter Your Weight
📚 What is Weight vs Mass?
Mass and weight are often confused, but they are fundamentally different:
Mass
- • Intrinsic property of matter
- • Measured in kilograms (kg)
- • Constant throughout the universe
- • Resistance to acceleration
Weight
- • Force due to gravity
- • Measured in Newtons (N)
- • Changes with gravity
- • W = m × g
📐 Key Formulas
Weight Formula
W = m × g
Weight = Mass × Gravity
Gravitational Force
F = G × M × m / r²
g = G × M / r²
🪐 Planetary Data
| Planet | Gravity (m/s²) | % of Earth | Mass | Type |
|---|---|---|---|---|
| ☿️ Mercury | 3.70 | 38% | 3.30×10²³ kg | Terrestrial |
| ♀️ Venus | 8.87 | 90% | 4.87×10²⁴ kg | Terrestrial |
| 🌍 Earth | 9.81 | 100% | 5.97×10²⁴ kg | Terrestrial |
| ♂️ Mars | 3.73 | 38% | 6.42×10²³ kg | Terrestrial |
| ♃ Jupiter | 24.79 | 253% | 1.90×10²⁷ kg | Gas Giant |
| ♄ Saturn | 10.44 | 106% | 5.68×10²⁶ kg | Gas Giant |
| ♅ Uranus | 8.87 | 90% | 8.68×10²⁵ kg | Ice Giant |
| ♆ Neptune | 11.15 | 114% | 1.02×10²⁶ kg | Ice Giant |
| ⯓ Pluto | 0.62 | 6% | 1.31×10²² kg | Dwarf Planet |
| 🌙 Moon | 1.62 | 17% | 7.35×10²² kg | Natural Satellite |
| 🪐 Ganymede | 1.43 | 15% | 1.48×10²³ kg | Moon |
| 🌕 Titan | 1.35 | 14% | 1.35×10²³ kg | Moon |
❓ Frequently Asked Questions
Q: What is the difference between mass and weight?
A: Mass is a measure of the amount of matter in an object and remains constant throughout the universe. Weight is the force exerted on an object due to gravity and varies depending on the gravitational field strength. On Earth, a 70 kg person has a mass of 70 kg everywhere, but their weight changes: 70 kg on Earth, 26.6 kg on Mars, and 177 kg on Jupiter.
Q: On which planet would I be heaviest?
A: Jupiter! With a surface gravity of 24.79 m/s² (2.53× Earth's), you would weigh 2.53 times more on Jupiter than on Earth. However, Jupiter is a gas giant with no solid surface - the gravity is measured at its cloud tops. A 70 kg person would weigh approximately 177 kg on Jupiter.
Q: Why does Saturn have similar gravity to Earth despite being much larger?
A: Surface gravity depends on both mass and radius: g = GM/r². Saturn is 95× Earth's mass but 9.5× larger in radius. Since gravity decreases with the square of distance, the larger radius compensates for the greater mass, resulting in surface gravity of 10.44 m/s² (1.06× Earth's).
Q: What would happen to my body on Mars with 38% Earth gravity?
A: With only 38% of Earth's gravity, you would experience reduced bone density over time (similar to astronauts on the ISS), muscle atrophy, fluid shifts to the upper body, and cardiovascular changes. Exercise 2+ hours daily and possibly medication would be needed to maintain health. However, you could carry 2.6× more equipment and jump higher!
Q: Can humans survive on planets with different gravity?
A: Humans can likely adapt to gravity between 0.5g and 1.5g for extended periods. Below 0.5g (like the Moon at 0.17g), severe bone loss and health issues occur. Above 1.5g (like Jupiter at 2.53g), cardiovascular strain and difficulty moving make long-term habitation extremely challenging. Mars at 0.38g is considered borderline but potentially habitable with countermeasures.
Q: How is surface gravity calculated for planets?
A: Surface gravity is calculated using Newton's law of universal gravitation: g = GM/r², where G is the gravitational constant (6.674×10⁻¹¹ N⋅m²/kg²), M is the planet's mass, and r is its radius. For gas giants like Jupiter and Saturn, "surface gravity" is measured at the 1-bar atmospheric pressure level since they have no solid surface.
Q: Why does the Moon have such weak gravity compared to Earth?
A: The Moon's gravity is only 1.62 m/s² (17% of Earth's) because it has much less mass (7.35×10²² kg vs Earth's 5.97×10²⁴ kg) and a smaller radius (1,737 km vs Earth's 6,371 km). Despite being relatively close in size, the Moon's lower density means it has far less mass, resulting in weak surface gravity. This is why astronauts could jump 6× higher on the Moon!
Q: Does my weight change at the poles vs equator on Earth?
A: Yes! You weigh about 1% more at the poles due to being closer to Earth's center (Earth is slightly flattened at the poles) and reduced centrifugal force from Earth's rotation. At the equator, you're further from the center and experience more centrifugal force, making you weigh slightly less.
🌟 Fun Facts
🦘 Moon Jumping
On the Moon, you could jump 6× higher than on Earth. A half-meter vertical jump becomes a 3-meter leap!
🏋️ Jupiter Gym
On Jupiter, you'd weigh 2.5× more. A 70 kg person would feel like 177 kg - walking would be exhausting!
☄️ Pluto
On Pluto, you'd weigh only 6% of your Earth weight. A 70 kg person would weigh just 4.2 kg!
🔴 Mars Life
Mars has similar gravity to Mercury (38%). Astronauts could carry heavier equipment but would need to exercise to maintain bone density.
🧑🚀 Space Colonization Considerations
Mars (38% Earth Gravity)
- • Bones lose density without countermeasures
- • Muscles atrophy more slowly than microgravity
- • Cardiovascular system adapts
- • Can carry heavier equipment
- • Exercise 2+ hours daily recommended
- • Children born there may never visit Earth
Moon (17% Earth Gravity)
- • Walking becomes bouncing/hopping
- • Severe bone loss concerns
- • Could jump 6× higher
- • Lifting heavy loads easier
- • Artificial gravity may be needed
- • Short stays preferred
Health Effects of Low Gravity
- • Bone density loss: 1-2% per month in microgravity
- • Muscle atrophy: especially legs and back
- • Fluid shift to head: "puffy face syndrome"
- • Vision changes: intracranial pressure
- • Heart becomes more spherical
- • Immune system weakens
Countermeasures
- • Resistance exercise (2+ hours/day on ISS)
- • Bisphosphonate drugs for bone loss
- • Centrifuge sleeping quarters
- • Lower body negative pressure
- • Proper nutrition (Vitamin D, calcium)
- • Rotating habitat designs
🔭 Gravity on Exoplanets
Beyond our Solar System, thousands of exoplanets have been discovered. Their surface gravity varies widely:
Super-Earths
Planets 1.5-10× Earth's mass may have 1.5-3× Earth's gravity. Standing would feel like carrying a heavy backpack.
Mini-Neptunes
Larger than Earth but smaller than Neptune. No solid surface, but atmospheric pressure creates "effective" gravity.
TRAPPIST-1 System
7 Earth-sized planets with gravity ranging from 0.62g to 1.14g - potentially habitable!
⚠️ Extreme Gravity Scenarios
Neutron Stars
Surface gravity: ~200 billion × Earth
- • A paperclip would weigh ~10 million tons
- • Atoms are crushed flat
- • Light is visibly bent
- • Time dilates significantly
Black Holes
Surface gravity: Infinite at event horizon
- • Nothing escapes, not even light
- • "Spaghettification" from tidal forces
- • Time stops at event horizon (from outside view)
- • Physics breaks down at singularity
White Dwarfs
Surface gravity: ~100,000 × Earth
- • Earth-sized but Sun's mass
- • You'd weigh millions of kg
- • Atmosphere only cm thick
The Sun
Surface gravity: 28 × Earth
- • A 70kg person would weigh 1,960 kg
- • No solid surface (plasma)
- • Temperature: 5,500°C at surface
🎮 Sports on Other Planets
Golf on Moon
Alan Shepard hit a golf ball on the Moon in 1971. With 1/6 gravity, balls could travel 2+ miles with a good swing!
Basketball on Mars
With 38% gravity, dunking would be easy! The rim might need to be 20+ feet high. Hang time would triple.
Swimming on Titan
With 14% gravity and liquid methane lakes, you could swim easily - but you'd need a heated suit at -179°C!
Weightlifting on Jupiter
With 253% gravity, lifting 100 kg would feel like 253 kg. Even walking would be exhausting!
High Jump on Mercury
With 38% gravity (like Mars), you could jump 2.6× higher. A 2m jump becomes 5.2m!
Flying on Titan
With low gravity and thick atmosphere, humans could fly by strapping on wings and flapping!
📜 Historical Context
Newton's Universal Gravitation (1687)
Isaac Newton discovered that gravity follows an inverse-square law: F = GmM/r². This allowed scientists to calculate the weight of objects on other planets for the first time.
Einstein's General Relativity (1915)
Einstein showed gravity is the curvature of spacetime caused by mass. This explains why massive objects like Jupiter have stronger gravity.
First Lunar Weight Measurement (1969)
Apollo 11 astronauts experienced 1/6 Earth gravity firsthand. Neil Armstrong's famous bouncing walk demonstrated the Moon's weak gravity.
Mars Rovers
Curiosity (899 kg on Earth) weighs only 341 kg on Mars. This affects landing calculations, driving, and arm movements.
🧪 Practice Problems
Problem 1: Astronaut on Mars
An astronaut weighs 70 kg on Earth. Their EVA suit weighs 45 kg. What is their total weight on Mars (g = 3.73 m/s²)?
Show Solution
Total Earth weight = 70 + 45 = 115 kg
Mars weight = 115 × (3.73 / 9.81) = 115 × 0.38 = 43.7 kg
Problem 2: Jump Height
If you can jump 0.5m high on Earth, how high could you jump on the Moon (g = 1.62 m/s²)?
Show Solution
Jump height is inversely proportional to gravity (same muscle force)
Moon height = 0.5 × (9.81 / 1.62) = 0.5 × 6.05 = 3.03m
Problem 3: Planet Mass
A planet has radius 2× Earth's and surface gravity 0.5g. What is its mass relative to Earth?
Show Solution
g = GM/r², so M = gr²/G
M_planet/M_Earth = (0.5g × (2r)²) / (g × r²) = 0.5 × 4 = 2
The planet has 2× Earth's mass
🚀 Escape Velocity
Escape velocity is the minimum speed needed to escape a planet's gravitational pull:
| Body | Escape Velocity | Comparison |
|---|---|---|
| 🌍 Earth | 11.2 km/s | Reference |
| 🌙 Moon | 2.4 km/s | 21% of Earth |
| ♂️ Mars | 5.0 km/s | 45% of Earth |
| ♃ Jupiter | 59.5 km/s | 5.3× Earth |
| ☀️ Sun | 617 km/s | 55× Earth |
🌕 Major Moons of the Solar System
Jupiter's Galilean Moons
- • Io: g = 1.80 m/s² (18% Earth)
- • Europa: g = 1.31 m/s² (13% Earth)
- • Ganymede: g = 1.43 m/s² (15% Earth)
- • Callisto: g = 1.24 m/s² (13% Earth)
Saturn's Moon Titan
- • g = 1.35 m/s² (14% Earth)
- • Only moon with thick atmosphere
- • Liquid methane lakes
- • Humans could fly with wings!
Neptune's Triton
- • g = 0.78 m/s² (8% Earth)
- • Retrograde orbit (orbits backwards)
- • Nitrogen geysers
- • Coldest known surface (-235°C)
Enceladus (Saturn)
- • g = 0.11 m/s² (1.1% Earth)
- • Water ice geysers
- • Subsurface ocean
- • Possible life candidate
🔴 Mars Colonization Details
Daily Life on Mars
- • At 38% gravity, a 70 kg person weighs 26.6 kg
- • Walking feels floaty but stable
- • Can carry 2.6× more equipment
- • Falls are slower, less damaging
- • Exercise 2+ hours daily to maintain health
- • May need weighted suits for bone health
Engineering Challenges
- • Landing requires less fuel
- • Buildings can be lighter
- • Cranes can lift more
- • Rockets need less thrust to launch
- • Water flows slower
- • Ballistic trajectories differ
Children Born on Mars
- • Would adapt to 38% gravity
- • Likely taller with lighter bones
- • May never be able to visit Earth
- • Earth's gravity would be crushing
- • First true "Martians"
Return to Earth Problems
- • Readaptation takes weeks/months
- • Increased fracture risk
- • Cardiovascular strain
- • Long-term Martians may not survive
🧮 The Mathematics of Gravity
Newton's Law of Gravitation
F = G × M × m / r²
G = 6.674×10⁻¹¹ N⋅m²/kg²
M = planet mass, m = object mass
r = distance from planet center
Surface Gravity
g = GM/r²
For Earth: g = 9.81 m/s²
Weight: W = mg
Why Saturn's Gravity ≈ Earth
Saturn is 95× Earth's mass but 9.5× larger radius. Since g ∝ M/r², we get g_Saturn = 95/(9.5)² = 1.05g. The larger radius compensates for the larger mass!
Gravitational Potential Energy
PE = -GMm/r (not mgh!)
PE = 0 at infinity
PE = mgh only valid near surface
📚 Key Takeaways
Key Concepts
- ✓ Mass is constant everywhere
- ✓ Weight depends on local gravity
- ✓ W = m × g
- ✓ Gravity depends on mass and radius
- ✓ g = GM/r² (surface gravity)
- ✓ Weight is a force (measured in Newtons)
Remember
- ✓ Jupiter has strongest gravity (253%)
- ✓ Pluto has weakest gravity (6%)
- ✓ Moon is ~17% of Earth's gravity
- ✓ Mars is ~38% of Earth's gravity
- ✓ Venus is ~90% of Earth's gravity
- ✓ Saturn is ~106% despite being huge
🔬 Gravitational Anomalies
Earth's Variations
Earth's gravity varies by location! At the equator: 9.78 m/s². At the poles: 9.83 m/s². This difference is due to Earth's rotation (centrifugal effect) and equatorial bulge.
Mascons on the Moon
The Moon has mass concentrations (mascons) that create gravitational anomalies. Early lunar missions had to account for these variations to maintain orbit.
Jupiter's Great Red Spot
Gas giants don't have solid surfaces. Their "surface gravity" is defined at the 1-bar atmospheric level. Actual gravity increases dramatically as you descend toward the core.
Neutron Stars
If you could stand on a neutron star, you'd experience ~200 billion g. A person would be crushed to a thin film of atoms instantly. These represent the most extreme gravitational environments.
🎓 Practice Problems
Problem 1: Mars Mission
An astronaut weighs 700 N on Earth. What would they weigh on Mars (g = 3.73 m/s²)?
Problem 2: Moon Jump
If you can jump 0.5m high on Earth, how high could you jump on the Moon (g = 1.62 m/s²)?
Problem 3: Jupiter Survival
A 80 kg person stands on Jupiter (g = 24.79 m/s²). What force would their legs need to support?
🌠 Exoplanet Considerations
Super-Earths
Planets 1.5-10× Earth's mass may have surface gravity 1.5-3× Earth. Humans might adapt to 1.5g, but 2-3g would be extremely challenging for long-term habitation. Every movement would require more effort.
Goldilocks Zone Planets
For a planet to be habitable, surface gravity between 0.5g and 1.5g is likely ideal. Too low and you can't retain atmosphere; too high and biological processes become difficult.
🏆 Quick Reference Card
Core Formula
W = mg
g = GM/r² (surface gravity)
Same mass, different weight on each planet
Useful Ratios
Moon: 0.165× Earth
Mars: 0.38× Earth
Jupiter: 2.53× Earth
Sun: 28× Earth
📚 Official Data Sources
⚠️ Disclaimer
⚠️ Disclaimer: This calculator provides estimates based on standard gravitational physics formulas and official planetary data from NASA JPL, ESA, and IAU sources. Results are intended for educational and general reference purposes. For space mission planning, engineering projects, or scientific research, always verify calculations with qualified physicists and official reference materials. Actual planetary gravity may vary slightly due to local topography, atmospheric effects, and measurement precision. Gas giant "surface gravity" values are measured at the 1-bar atmospheric pressure level. Health effects of different gravity levels are approximate and individual responses may vary significantly.
For educational and informational purposes only. Verify with a qualified professional.
🔬 Physics Facts
On the Moon you could jump 6× higher than on Earth.
— NASA
Jupiter has no solid surface; gravity is measured at cloud tops.
— NASA JPL
Mars gravity (38%) is similar to Mercury despite different sizes.
— ESA
Saturn has similar gravity to Earth (106%) despite being 95× more massive.
— Physics.info
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