1. What is Earth's Gravity?

Earth's gravity (g) varies slightly depending on location due to factors like latitude and altitude. The standard gravity is defined as 9.80665 m/s², but actual values range from about 9.78 m/s² at the equator to 9.83 m/s² at the poles.

2. How Does the Calculator Work?

The calculator uses the international gravity formula:

Where:

• \( g_0 \) — Standard gravity at equator (9.7803267714 m/s²)
• \( a \) — Latitude coefficient (0.0052790414)
• \( b \) — Latitude coefficient (0.0000232718)
• \( c \) — Altitude coefficient (0.000003086 m/s² per meter)
• \( latitude \) — Geographic latitude in degrees
• \( altitude \) — Elevation above sea level in meters

Explanation: The formula accounts for Earth's oblate shape (greater gravity at poles) and reduced gravity at higher altitudes.

3. Importance of Gravity Calculation

Details: Precise gravity values are essential for geophysical surveys, metrology, space missions, and scientific experiments requiring high precision measurements.

4. Using the Calculator

Tips: Enter latitude in decimal degrees (-90 to 90) and altitude in meters above sea level. For best results, use precise coordinates.

5. Frequently Asked Questions (FAQ)

Q1: Why does gravity vary with latitude?
A: Earth's rotation creates centrifugal force that counteracts gravity, and the planet's oblate shape means you're farther from the center at the equator.

Q2: What is standard gravity?
A: 9.80665 m/s² is the conventional value representing average gravity at Earth's surface, used for definitions like kilogram-force.

Q3: How much does altitude affect gravity?
A: Gravity decreases by about 0.3086 mGal/meter (0.0003086 m/s² per meter) of elevation gain.

Q4: What's the difference between g and G?
A: g is local gravitational acceleration (m/s²), while G is the universal gravitational constant (6.674×10⁻¹¹ N·m²/kg²).

Q5: Does local geology affect gravity?
A: Yes, but this calculator doesn't account for local density variations which typically cause variations of ±0.01 m/s².