Gravity is the force that pulls two objects toward each other.
It is one of the four fundamental forces of nature, and it affects everything with mass.
📌 Example: Gravity pulls you toward the Earth, which is why you don’t float away!
🧠 Who Discovered Gravity?
| Scientist | Year | Contribution |
|---|---|---|
| Isaac Newton | 1687 | Formulated the Law of Universal Gravitation |
| Albert Einstein | 1915 | Described gravity as the curvature of space-time (General Relativity) |
🔢 Newton’s Law of Universal Gravitation
F=G⋅m1⋅m2r2F = G \cdot \frac{m_1 \cdot m_2}{r^2}
Where:
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F = gravitational force (in newtons)
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G = gravitational constant (6.67 × 10⁻¹¹ N·m²/kg²)
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m₁ & m₂ = masses of two objects
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r = distance between the centers of the objects
📌 Bigger mass → stronger force
📌 Larger distance → weaker force
🌎 Why Gravity Matters
| Gravity Helps Us... | Example |
|---|---|
| Stay on the ground | You don’t fly off into space |
| Drop objects | Apples fall from trees |
| Keep the Moon in orbit | Moon causes ocean tides |
| Keep planets around the Sun | Solar system remains stable |
| Hold the atmosphere around Earth | Air stays close enough for us to breathe |
🌌 Gravity in the Universe
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The Moon’s gravity is about 1/6 of Earth’s, which is why astronauts bounce.
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Black holes have gravity so strong that even light cannot escape.
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Stars and galaxies stay together because of gravity.
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Tides in oceans happen due to the Moon’s gravitational pull.
📘 Fun Facts About Gravity
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You weigh less on the Moon than on Earth!
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Gravity is the weakest of the four fundamental forces, but it acts over infinite distances.
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The International Space Station (ISS) is constantly “falling” around Earth — this creates weightlessness.
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The Sun’s gravity keeps all the planets in orbit. Without it, we’d float away into space!