Sunlight is just over eight minutes old by the time it reaches us here on Earth. Or to put it another way, if there's a brief flare on the surface of the Sun, it would have already been and gone by the time our scientists get to watch it.
There is roughly 150 million kilometres between the Sun and Earth. Sunlight takes about three and a half minutes to fly past Mercury, Venus in six minutes, then us at eight. Light from our nearest star Proxima Centauri takes over 4 years to arrive.
So, why am I writing all this? Well it got me hypothetically thinking, it works both ways. Everything we do here on earth is bouncing back out to space. It's not just light that gets sent out into the vacuum either, it's radio waves too, consisting of mobile phones, TV, internet chat sessions, emails, video calls, earth is a noisy place. There is nothing in the way to stop our broadcasts from going on forever.
And here's my main fantastic point, If I was 150 million kilometres from Earth with a really powerful telescope and computer to process it all, then I could witness life on earth eight minutes ago.
Providing we are at the right distance from Earth one could re-witness any moment at any time in history. You could witness your Grandparents' picnic in the park on a sunny day. Or relive any cherished personal moments, imagine seeing yourself re- fall in love again for the first time.
I'm sure a Physicist would find fault with my thinking, but I don't care. I like the thought that everything is recorded and locked into this universe, nothing is lost in time. It gives meaning and weight to every moment.