Reflections on our place in the Cosmos

The term “Selfie” has entered the lexicon for a picture, usually taken with a cellphone camera, of one self; below is a “Selfie” – of our own mother Earth! This is a picture of Earth taken by the aptly named Curiosity rover from the surface of Mars. NASA has kindly placed an arrow so that you will not miss our planet’s “Selfie”. This is how our home planet would look to a Martian looking at their night sky. On the plus side, this show we are also a “heavenly” body as long as you are looking at Earth from some other vantage point in the Universe! But like other iconic pictures of Earth from space – the famous “Earth rising" from Apollo 8 and the “Pale Blue Dot” by Voyager 1 – it shows how insignificant we are compared to the solar system. Forget even imagining our relative size compared to our own Milky Way galaxy – let alone the entire universe! We have been blessed to be a generation to actually see how the whole Earth would look from outer space. And how small and insignificant we are, even when looked at from Mars, which on a cosmic scale is just our own back yard.


Picture 1: Picture of Earth from Mars, taken by the Curiosity rover

Picture 2: "Earth rising" - taken in 1968 by Apollo 8 astronaut William Anders

No one said it more beautifully and more poetically than the late, great Carl Sagan: Let me quote his feelings of awe, humility and humanity on seeing the beautiful, tiny and fragile looking picture of earth taken from the Voyager 1 spacecraft from over 6 billion km away:

Picture 3: "The pale blue dot", picture of Earth taken in 1990 by Voyager 1, from about 6 billion kilometers from earth

“From this distant vantage point, the Earth might not seem of particular interest. But for us, it's different. Consider again 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 posturing, 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.”

If there is one common theme in the developments in astronomy over the last several centuries, ever since the first human looked up at the night sky and wondered “what is out there” is this: with each generation, the size and grandeur of our cosmos gets bigger and ever more mind blowing. For the longest time, and still for many religions, Earth was thought to be the center of the cosmos; since the time of Copernicus science has shown us that we are not in any privileged position at all at the grand cosmic scale; we are just a tiny rock orbiting an average star at the periphery of this vast galaxy, which in turn is part of a cosmos vastly bigger. Until the time of Hubble, we thought Milky Way was the whole universe and those distant faint lights nothing but a “nebula”. Hubble and others found those tiny discs of lights were in fact entire galaxies, as big or bigger than our own Milky Way but separated from us by millions and billions of light years away! Now most cosmologists think the whole visible Universe itself – spread across an unimaginably large distance of nearly 14 billion light years  - is just again a small “pocket universe”, a speck among a vast array (10⁵⁰⁰ according to some string theory interpretations, a number so huge, it is vastly more than the total number of atoms in the entire visible universe) of other Universes, each away from us not just in space and time, but also likely having even basic nature of reality itself different, like beings and matter with additional spatial dimensions instead of the familiar 3! The more science advances, the more humbling our place in the grand scheme of things becomes.  If a sage were alive today and wants to create a new religion, it is very unlikely he would place our small world as the center of the universe and the primary obsession of a creator of a cosmos that is so vast, old and profound, our common sense notions of space and time totally fails us to grasp the true grandeur of it all. We have been the first generation of humans to see Earth from space; and the first generation to actually see how the entire universe would have looked just 380,000 years after the big bang (picture 4, Planck satellite image of the baby universe ). Thanks to the works of generations of scientists and philosophers, we are lucky to be living at a time when we can truly be awed at the majesty of it all, a description of the cosmos no religious description does not even come close to match.

Picture 4: Universe at 380,000 old – our Baby Universe based on cosmic microwave back ground radiation, taken by the Planck spacecraft