Time is Chemistry.

All structures are unstable.
In one of his speeches Eckhart Tolle tells about his encounter with the Malibu´ Sutra: he was in Los Angeles walking in a periferical area, when he entered an abandoned house that burned down years before.
Between the remaining walls grew with time a beautiful wild garden, startled by this beauty eckhart turns and read this warning sign:

Warning! All structures are unstable.

he names it the Malibu´ Sutra

That was indeed the nature of all elements.

When we look at time we are looking at transformation.

An old apple is not old, is simply rotting down becoming something else.

Our body grows and transforms, it gain and loses capacities, because of his unstable nature.
Elder people is less capable of retain and assimilate water in their skin, their system will never be new and it needs more and more care in order to keep a minimum functionality.

Looking at a single organism it´s easy to see what time has done to that organism, but when your attention focuses over an entire environment it´s less easy to see the action of time.

When you look at nature there is a cyclical order of transformation.
A forest will not grow old and dye, a tree will, but the environment renovates and feeds itself.
It may all burn down with a vulcanic eruption, blown by an atom bomb.
But as Michael Chricton writes in The Lost World (not sure which book): may atomic war erase humanity and most of earthly life, nature will spring again.

A famous story in support of this argument is the one of the scientific team that protected by anti radioactive gear visits an island in the pacific ocean.
The sole is completely vetrified by atomical testing.
The equipe wants to verify if any living organism has survived and not long after they set up some traps for small sized creatures, they start capturing lots of big fat rats.

The self-destructive potencial of humanity it´s directly proportional to his dependency from environment, but a single tiny seed can outstand the destructive power of a thousand H bombs (yes, yes Ganja seeds also).

What are we compared to the creative power of mother earth and the universe?

we are forms.

The matter that makes our bodyes has always been on earth.
You are a form in trasformation, you have never been created and you will never be destroyed, what we are is not contingent, is there, unseparable and necessary as everything else exists.

If you are scared about your consciousness dying than ask yourself wether you are your consciousness or not.

Spiritual teachers say no you are not your thoughts,

I haven´t yet myself given an answer to this.