How do we know if any form of life is active on extra-solar planet?
As we know, so far it is not possible to travel on planets of our solar system. Evaluation of planet’s climate, gravity, motion, presence of gases, pressure of environmental gases and water by means of photographs cannot deliver realistic information. Such planets appears so tiny (like earth appeared when Voyager clicked earth’s snap shot from 4 billion km and Prof. Carl Sagan’s famous speech on "pale blue dot") and cannot be evaluated if it really supports the life. If you see earth’s pale blue dot snap, no one can make-out (from a habitable extra-solar planet) that this blue dot has grown very intelligent life on it. Earth itself appears difficult to identify from this distance then what’s there on it is just impossible to determine. For example, if we find habitable planet on just opposite arm of the Milky Way, how to conclude that it has something like earth.
Here is a famous quote of Carl Sagan.
The "Pale Blue Dot" … From this distant vantage point, the Earth might not seem of any particular interest.
But for us, it’s different. 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.
– Carl Sagan, 1994
we don’t, and Carl will live forever
Related posts:
- Does the light of the sun reach and illuminate every planet in our solar system?
- Could telescopes eventually clearly show extra-solar planets?
- If I was in a space ship somewhere else in the solar system looking back at Earth,would I see stars?
- If I was in a space ship somewhere else in the solar system looking back at Earth,would I see stars?
- How do we know if any form of life is active on extra-solar planet?
