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  1. Speed of light - Wikipedia

    The speed of light in vacuum, often called simply speed of light and commonly denoted c, is a universal physical constant exactly equal to 299,792,458 metres per second (approximately 1 billion kilometres …

  2. How Fast Does Light Travel? | The Speed of Light - Space

    Oct 29, 2024 · The speed of light traveling through a vacuum is exactly 299,792,458 meters (983,571,056 feet) per second.

  3. Speed of light | Definition, Equation, Constant, & Facts | Britannica

    Dec 15, 2025 · speed of light, speed at which light waves propagate through different materials. In particular, the value for the speed of light in a vacuum is now defined as exactly 299,792,458 metres …

  4. What Is the Speed of Light? - Science Notes and Projects

    Apr 11, 2021 · The speed of light is the rate at which light travels. The speed of light in a vacuum is a constant value that is denoted by the letter c and is defined as exactly 299,792,458 meters per second.

  5. Speed of light: How fast light travels, explained simply and clearly

    Jan 23, 2024 · The speed of light is a fundamental constant, approximately 299,792,458 meters per second. It's the same for all observers and hasn't changed measurably over billions of years.

  6. The Speed of Light: Why It’s the Ultimate Speed Limit

    May 23, 2025 · From the earliest experiments to the latest discoveries in cosmology and quantum mechanics, the speed of light remains the ultimate speed limit—an elegant, immutable boundary that …

  7. The Speed of Light: The Barrier That Limits Our Reach

    3 days ago · At 299,792,458 meters per second, light doesn't just travel—it quietly dictates the limits of connection, the reach of knowledge, and the permanent isolation between distant worlds.

  8. All About the Speed of Light and What It Measures - ThoughtCo

    May 6, 2025 · The speed of light is the fastest known speed in the universe and is a cosmic limit. Light travels at 299,792,458 meters per second in a vacuum, but it slows in different materials. The speed …

  9. Speed of Light - Definition, Examples, Quiz, FAQ, Trivia

    The speed of light is how fast light travels through space. In a vacuum (empty space with no air or other matter), light travels at an incredible 299,792,458 meters per second!

  10. What Is the Speed of Light? The Speed Limit of the Universe, Explained

    Nov 23, 2024 · The speed of light, sometimes abbreviated as c, is a universal maximum posted speed that causality will enforce. It's the greatest speed at which any known substance or object can travel.