Some 3,000 planets have been identified outside of our solar system. A whopping 1,284 of those were announced just last month by the team behind the Kepler space telescope. What was once a difficult and uncommon discovery has become something of the norm – new planets seem to pop up regularly. “Improvements in astronomical observation technology have moved us from retail to wholesale planet discovery,” writes University of Rochester professor of astrophysics Adam Frank in an op-ed piece for The New York Times.
Frank’s piece, titled, “Yes, There Have Been Aliens,” argues that, at some point before humans existed, there were probably aliens. Frank refers to an equation conceived in 1961 by a man named Frank Drake (yes, their names are easy to confuse) who was invited to host a conference on the possibilities of communication between solar systems. Drake decided to create an equation for the event, which attempted to calculate how many advanced civilizations existed off of Earth, since the quantity of advanced civilizations increases the chances of interstellar contact.
Here’s the Drake equation: N = R* x fp x ne x fl x fi x fc x L
And here’s what it means (bear with us because it gets complicated):
N stands for the number of civilizations that we may be able to communicate with.
R* stands for the average rate at which stars form in our galaxy.
fp stands for the fraction of these stars which have planets.
ne stands for the number of planets that can support life, per star that has planets.
fl stands for the planets that can support life, which actually develop life.
fi stands for the fraction of planets with life, which then develop intelligent life.
fc stand for the fraction of intelligence life that then develops technology to send of detachable signals.
And, lastly, L stands for the length of time that these civilizations can send out detectable signals.
Frank and his team took license to eliminate some of these variables. For example, he writes, “Instead of asking how many civilizations currently exist, we asked what the probability is that ours is the only technological civilization that has ever appeared. By asking this question, we could bypass the factor about the average lifetime of a civilization. This left us with only three unknown factors, which we combined into one ‘biotechnical’ probability: the likelihood of the creation of life, intelligent life and technological capacity.”
A few calculations later, Frank determines that “even if this probability is assumed to be extremely low, the odds that we are not the first technological civilization are actually high. Specifically, unless the probability for evolving a civilization on a habitable-zone planet is less than one in 10 billion trillion, then we are not the first.”
To be clear, and before your gets too exited about meeting ET, Frank’s position isn’t that aliens do exist but that, according to the Drake equation, aliens have existed at some point in the history or the universe.
