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Planet Mass Formula:
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The planet mass formula \( M = \frac{g \times r^2}{G} \) calculates the mass of a celestial body using its surface gravitational acceleration, radius, and the gravitational constant. This formula is derived from Newton's law of universal gravitation.
The calculator uses the planet mass formula:
Where:
Explanation: The formula relates a planet's mass to the gravitational force it exerts at its surface, allowing calculation of mass from measurable surface gravity and size.
Details: Calculating planetary mass is fundamental in astronomy for understanding a planet's composition, density, gravitational influence, and orbital characteristics. It helps classify celestial bodies and study planetary formation.
Tips: Enter gravitational acceleration in m/s², radius in meters, and gravitational constant (default is 6.67430e-11). All values must be positive numbers.
Q1: What is the standard value of G?
A: The gravitational constant is approximately 6.67430 × 10⁻¹¹ m³/kg·s², though precise measurements may vary slightly.
Q2: Can this formula be used for any celestial body?
A: Yes, this formula works for planets, moons, stars, and any spherical celestial body with measurable surface gravity.
Q3: How accurate is this calculation?
A: Accuracy depends on the precision of input values. For real astronomical applications, factors like planetary oblateness and rotation may require adjustments.
Q4: What units should I use?
A: Use SI units: meters for radius, m/s² for gravity, and m³/kg·s² for G to get mass in kilograms.
Q5: Why is the gravitational constant so small?
A: The gravitational constant has a small numerical value because gravity is the weakest of the fundamental forces, requiring very sensitive equipment to measure.