Part 2/10:
Among the four fundamental forces of nature—gravity, electromagnetism, the weak nuclear force, and the strong nuclear force—gravity holds a special place. It governs the attraction between masses, and despite its apparent simplicity, gravity remains shrouded in mystery. Isaac Newton's 17th-century Law of Universal Gravitation was the first significant mathematical description of this force. Yet, nearly 500 years later, gravity still eludes a complete understanding.