The Reliable Sun

The sun is vanishing in the west,
Going to its nightly rest,
Slowly moving from our gaze,
As it's done throughout the days
The earth's existed; should it drop
Right out of sight, then life would stop.
But every morning it returns,
Thus allaying all concerns,
That it might have disappeared,
And the worst that earth has feared
Has come to pass; without the sun,
Of life on earth there would be none.