The Beautiful Milky Way
Growing up in India I remember it was hot in summer and, having no air-conditioning, we often slept on the roof of our house. I would spend endless hours staring at the brilliantly lit night sky and marvel at all the stars out there. My father was posted in the boonies in the state of U.P. in Northern India, building roads and other infrastructure for the Public Works Department of the government. Being in remote locations meant truly dark nights, unpolluted by town lights, and so the stars seemed ablaze like so many twinkling bulbs hung in the sky. You could see the Milky Way streak across a large swath of sky like a shimmering veil and you could spot some familiar patterns, such as the belt of Orion, night after night, rising and falling as the whole show rotated slowly in a giant circle around the pole.
I was told by my mom later that, when six years old, I was fascinated by the stars and kept asking endless questions about them. What were they? How come they didn’t fall down. How long would it take to count them? And so on. My mom said they were other worlds, very far away, too numerous to count and that unknown, strange supercreatures lived on them. Aliens with superpowers perhaps, aliens who could see everything we were doing and could influence us through magic etc. My questions kept coming and my mom would answer them patiently and with wondrous touches until she dozed off, and I would keep staring and dreaming of these mysterious worlds beyond our reach.
My fascination with astronomy has continued unabated. I still have endless questions, but now I realize that I am not alone. There are many, many others like me who are exploring the skies and trying to answer age old questions. And thanks to our great exploration programs and our collective will to find out more we have some fascinating insights into the Universe. I have been associated with SETI for a few years now and ever since I first visited them (See my blog from then, here) I have been blown away by the extent to which they are passionate about studying our universe and dedicated to collecting extra-terrestrial evidence of life.
Kepler's “Flashlight” into Space
And now we have the fascinating Kepler Mission whose “number one goal is to find a habitable planet, a second Earth.” The Kepler probe is a large telescope in synchronous orbit with the earth always facing away from the Sun so that it can watch the stars at all times. It can see a small swath of stars and has photometry to detect planets indirectly from their small occultation of light as they pass in front of their stars. It is like flashing a small flashlight into the giant gloom of the universe – Kepler can see only about 100,000 stars in our outer galaxy neighborhood (up to 3000 light years away maximum), a mere 0.00005% of the total stars in the galaxy, which is only one of 100,000,000,000 estimated galaxies that are in the observable universe.
But Kepler is already giving us a great picture of what’s out there. See this great article in the Wall Street Journal from last Friday. It has found 1235 candidates for planets rotating around other suns of which 54 are in the habitable zone. That means that 54 planets have been found which have conditions similar to earth and could sustain life.
A Planet Circling two Suns.
And Kepler has given us some mouth-watering surprises:
It found a planet that revolves around a two-star system! Two stars that themselves rotate around each other. Imagine multiple sunrises at odd hours of the day and multiple sunsets to serenade! See the great pic to the right.
The startling facts that we are now learning which makes extra-terrestrial life very, very likely are:
There are more planets than there are stars in the Universe! And we have 200 billion stars in our galaxy alone. It seems that most stars have planets and many have more than one. So let’s say we take a conservative estimate of 200 billion planets in our galaxy.
From the preliminary analysis of the Kepler exoplanets it seems that about 4% of the planets are habitable and have the potential to generate life as we know it. That means that we could have 8 billion planets capable of life in our galaxy.
So even if one such planet actually develops life out of 1000 we would have 8 million earths out there with life. If only 1 in 1,000,000 do we would still have 8000 earths in our galaxy with life.
And since there are at least 100 billion galaxies out there …. well you do the math.
Bottom line: It seems that we are not alone and exciting news is due from all the alien watchers any time now!
By the way Kepler cost us $600 million. Government spending? I prefer to think of it as American Exceptionalism.