Sunday, 22 February 2015

"Like a mote of dust suspended in a sunbeam"

Whenever I look at the night sky, I remind myself that each of these tiny dots of light could potentially be harboring life forms and sentient being like us. Someone up there might be wondering and going through the same thought process while looking at our home. So how our home planet would look like from an outsider’s prospects?

The big blue marble (2002) - Asian side
At a distance of around 50,000 kilometers, our earth looks like a big blue marble. Here cloud cover, oceans, hint of vegetation and outlines of continents are visible but there are no national boundaries or sign of any human development.

Earthrise
Our next stop would be moon at nearly 4,00,000 Km. On the near side of moon, earth would always be hanging in the sky, rotating and going through the phases. It would also be huge and very bright, like more than thirteen moons in our night sky. This vista alone should be worth buying a place in the lunar colony. But beware that on the far side of Moon, you won't be able to see Earth at all. So choose wisely.

Earth in the Martian sky
The average distance between planet Mars and Earth is around 225 million kilometers. This is more than 500 times than the distance of Moon from Earth. At this distance , our earth is just one of the bright dots in the Martian sky. 

Another famous photograph of earth is from the vicinity of Jupiter. It was taken by the Cassini spacecraft at the distance of a billion kilometers on July 19, 2013. So where is the Earth? You will have to look under the rings of Jupiter and magnify to locate it.

A pale blue dot
But the most famous of all is the "pale blue dot" photograph. It is taken at the request of famous scientist and writer Carl Sagan in February 1990 by Voyager 1 spacecraft nearly at the edge of our solar system. At a distance of six billion kilometers, our Earth looks like a tiny mote of dust suspended in a sunbeam. In the words of Carl Sagan:

"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 ... 

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. 

... 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."


Image Credit: NASA/JPL 

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