Are We Alone?

Barely visible inside the circle is our planet, Earth.  This is the most distant image ever taken of our home world.  It was taken by Voyager 1 in 1990 at a distance of approximately 6 billion kilometres (5.6 light HOURS).

Credit for the photo must go to Carl Sagan for insisting that Voyager 1, as it left our solar system, turn around and take one last picture.  It is called the Pale Blue Dot.

Consider the task astronomers have taken upon themselves now.  This morning a new space telescope called Kepler was launched.  Its task is to detect similar sized planets, from a distance of thousands of light YEARS.

Over three hundred new planets have been discovered in the past fifteen years orbiting stars in our galaxy.  The instruments used have limited the discovery to very large planets by either measuring the gravitational wobble they produce in their home suns as they orbit, or by measuring the tiny decline in light that occurs as they pass across the face of their suns.

It is the latter technique that Kepler will employ to find Earth-like planets, a task of incredible precision.  Many media articles are suggesting that Kepler will discover life on other planets.  Not so.  It will simply determine if other planets similar in size to Earth exist and if they are in orbits where temperatures are conducive to what we think Life requires.  

If we find such planets then we may begin to really appreciate the probability that we are not alone.  We should know in a few years.

Photo Credit: Voyager 1. NASA.