When you look up at the stars on a dark night, are you sometimes overwhelmed at the sheer scale of it all? Does it occasionally make you feel insignificant, like a tiny speck of dust whose problems don't actually amount to a hill of beans? Not me.
Why do I feel this way, why this perspective? Well, by just existing we are part of something incalculably vast, a universe of matter and energy both seen and unseen, a universe where substance cannot be created or destroyed, only transformed. To me, (notwithstanding some issues around quantum mechanics which I won't go into now) this means what we know of as 'our' universe could not exist in the same way without a single atom that's already here. Or to put it another way, there can be only so much matter in the universe and however small you are, you have to be here. That makes you and me and everything you see or do not see (so long as it as some kind of mass and/or energy) absolutely and inextricably a part of the whole. The universe, this universe, literally would not be the same without you. You are necessary.
You are made of stuff that is as old as the planet,
Of course, as Frank puts it so eloquently above, 'you' and your sense of being (consciousness) will probably never come together again after your time is up, but the trace elements of you, parts of your physical body, will go on and on - transforming and transmuting and becoming parts of other living things. In fact, as PhD Astrophysicist Ethan Siegal calculated, there are hundreds of billions of King Tut's atoms inside you right now, hundreds of billions of Hitler's or Caesar's atoms inside you, and if you want to go even further back, trillions of atoms that were part of a Tyrannosaurus Rex.
As for the effects or events you have brought about in this world - the deeds you have done, things you have made, the children or grandchildren you may have raised or the people you have mentored - actually anyone you have come into contact with, the ripple of these interactions will also continue ad infinitum. Every single thing you do, however small, creates a ripple in space and time. Every meeting changes you and the person you meet in some way. You influence everyone, be it just with a look, a smile or by throwing up in their taxi. My personal philosophy is to try and create ripples that make people happier and reduce suffering. That's pretty much it in a nutshell, it's not complicated. Of course sometimes I get it wrong and sometimes I'm a twat, that's just the way life is. But I don't sweat the fact that I'm human and screw up from time to time, I just try again and work harder on my ripple generation.
The sky at night is my duvet, the stars are my nightlights. I am happy and content to be here, and I always will be.
The cosmos is within us. We are made of star-stuff. We are a way for the universe to know itself.” Carl Sagan