The speed of light in vacuum, commonly denoted c, is a universal physical constant important in many areas of physics. Its value is exactly 299792458 metres per second, as the length of the metre is defined from this constant and the international standard for time. According to special relativity, c is the maximum speed at which all matter and information in the universe can travel.
It takes sunlight an average of 8 minutes and 20 seconds to travel from the Sun to the Earth.
Photons are created by fusion reactions inside the Sun's core. They start off as gamma radiation and then are emitted and absorbed countless times in the Sun's radiative zone, wandering around inside the massive star before they finally reach the surface.
These photons striking your eyeballs were created tens of thousands of years ago and it took that long for them to be emitted by the sun. Once they escaped the surface, it was only a short 8 minutes for those photons to cross the vast distance from the Sun to the Earth.
As you look outward into space, you're actually looking backwards in time.
"Your shadow is a confirmation that light has traveled nearly 93 million miles unobstructed, only to be deprived of reaching the ground in the final few feet thanks to you."
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