When you light a candle near your face, or turn on the light in the centre of the room, photons, little packets of light, fly out of it and strike your eye. The time it takes to get from the candle to your eye is very small (10 to the power of minus-something-big seconds). Light takes a second to travel 7 times around the world.
If those photons are created when you turn on the light or spark the wick, then by the time they reach your eye, they'll have existed for a tiny amount of time. Time briefer than the thought 'that-'
When light leaves the surface of the sun - so, when photons leave the surface of the sun, they take eight minutes to reach the earth. That'll tell you how far the sun is: it takes 3500 times longer to get here than to circumnavigate the earth. (A flight to Australia might take 24 hours non-stop. At the same speed, a flight from the sun would take twenty years).
If those photons are created when they leave the surface of the sun, then by the time they reach your eye, they'll have existed for as long as it takes to push down a toaster, boil a kettle, make some tea, take the popped up toast, butter it and go outside.
So, think about that: when you push down the toast, there is a photon leaving the surface of the sun. It moves through the empty void, part of a vast wave of light spreading out in all directions. This particular photon, in the last few millionths of seconds in its existence, crosses earth's path, pierces the atmosphere like a pin, rebounds off a speck of dust in that atmosphere. Then, just as you look up from eating your toast, the photon hits your eye.
You see the blue sky.
.
.
.
.
But...this photon, along with all the rest of the sun's light, wasn't created eight minutes ago. It left the surface of the sun eight minutes ago. But it was created earlier than that in the center of the sun.
This photon that struck your eye, or another that warms part of your face as you stand out on the street - these photons were created between 10,000 to 170,000 years ago.
When you stand on the street, feeling the chill winter sun, and look at the sign on a wall, what strikes your eyes, face and skin has existed from before ancient Greece and the Pyramids.
Sunlight is ancient.
And you just obsorbed it.
It struck your body and went out.
REFERENCES:
Astronomy Cast: The Sun, Spots and All (With the figure of 10 million year, which is apparently wrong, sadly...)
