Space factThe Universe
Light moves at 299,792,458 meters per second in a vacuum, but it slows down in different materials. In water, it’s about 25% slower. In diamond, it crawls at less than half its usual speed. Scientists have even found ways to slow light down to a near stop using supercooled atoms. But here’s the wild part—when light exits these materials, it instantly resumes its full speed. It never “accelerates” back up. That’s just how light works.
299,792,458 m/s
Speed of light in a vacuum