I bought a new wall poster for the cottage this week to replace a wall hanging which I've purloined for my new bathroom at home.

During the last few months, we've done an awful lot of solitary walking and thinking (as well as bathroom plumbing and tiling!) and, being of a certain age and caught in a deadly pandemic, I frequently ponder the place and reason for Mankind's place in the universe. Plodding round Rudyard Lake with Scout, I can apply my otherwise disordered mind to Deep Thought.

Many years ago, when I was quite a young man, I was enthralled by a television series entitled "Cosmos" which was written and presented by the late , great, Carl Sagan, American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, poet and surely one of the greatest ever science communicators.

As Director of the Voyager 1 imaging team at NASA in the 1970s & 80's, it was Sagan's brilliant idea to have the Voyager's camera turned around at the end of it's mission, beyond Neptune, just as it left the realms of the solar system and about 6 billion kilometres from earth. This was when digital cameras were in their infancy and only multi-billion dollar space projects could afford to have them. At this extraordinary range, the imaging team succeeded in capturing a stunning image, in which the Earth shows as a pale blue dot just 1/4 of a pixel in the inky blackness of interplanetary space.

A quirk of the direction of the shot relative to the position of the sun, meant that "lens flare" left some faint colour fringes across the image. It's an image not just of astonishing aesthetic beauty, but one which emphasises our extreme remoteness, our isolation and our infinite smallness too.

It's an image which has always had a profound impact on me and, I'm sure, on many others. I always ponder this image when the World seems topsy-turvy and riven by stupidity and petty human bickering.

Sagan himself put it exquisitely in his truly poetic passage for the TV series.

Look again at that dot.
That's here. That's home. That's us.
On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives.
The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there--on a mote of dust suspended in a sunbeam.

The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known.