August 11, 2015

Earth's Distant Twin

We are not alone-or are we? Is there life elsewhere in the universe? We have found water on Mars, indicating the possibility that there may be or may have been some kind of life on that planet. But now NASA has come up with one better, a planet with the burdensome name of Kepler 452b. We'll call it Kepler for short.

Kepler is just distant enough from its sun to have the right climate for life.  It has been dubbed a Goldilocks planet—not too hot, not too cold.  It is estimated that it is 6 billion years old, compared with earth’s 4.54 billion years.

The SETI Institute (Search for Extra Terrestrial Intelligence) is a charitable organization which in the past has had US governmental funding.  While NASA has dipped its toe in the Milky Way, so to speak, indicating it is searching for life, SETI is going one better—intelligent life.  But how would we determine if there is intelligent life on Kepler? 

Here we encounter problems of time and distance.  Kepler is 1,400 light years from us.  A light year is the distance that light travels in a year.  That distance is roughly 6 trillion miles, 6 followed by 12 zeros. The current scientific understanding is that nothing can travel faster than light, though some efforts are being made to unseat that conclusion.  For our purposes, we’ll stick with that. 

Multiply the speed of light by 1,400 and we get roughly 6 trillion miles, 6 followed by 12 zeroes.  The task is to cover that distance.

If we can send a signal at the speed of sound, roughly 345 meters a second, it would take something a bit less than a million years to contact Kepler, another million to hear back if anyone received the message, understood it, and was in the mood to reply. 

Earth is roughly 4.54 billion years old, and scientists have estimated that we may have another 5 billion years before the sun becomes a red giant and swallows us up.  But please don’t let that keep you up at night.

It is in the realm of science fiction.

We may have a better shot at determining if life has existed on other planets in our own solar system.  SETI may still ask if there is intelligent life in the universe.  One could argue that there might be such on earth, though that is certainly open to question.