Humans Aren't Alone or Special - The Drake Equation

The inspiration for this post came when I made my brother watch Carl Sagan's Cosmos with me. He was floored by the fact that scientists weren't in debate about the fact that intelligent civilizations are thought to exist beyond our own. I thought that was somewhat common knowledge?

There is actually an equation for figuring out the odds of other intelligent civilizations existing - it's called the Drake Equation. I first ran across the Drake Equation in The Five Ages of the Universe: Inside the Physics of Eternity (the Harold Washington Library [in Chicago] has at least two copies). Quite possibly the most formative book I've read. Perhaps this is an overstatement but it was in some way the culmination of my spiritual ideas? It's hard to explain and I don't feel like it. Nothing goes beyond astrophysics. It is nature in its entirety and the culmination of literally everything. To understand it you have to understand how everything fits together at a fundamental level. Yup, sounds like boule-shit... yet totally true. Of course, although we understand quite a bit we really don't truly understand some very fundamental natural phenomenon.

Anyways, this is the Drake Equation:

N = R* x fp x ne x fl x fi x fc x L

Where:

N = The total number of civilizations in our galaxy (gasp).
R* = Total number of stars suitable for life (or rather their formation rate). About 1% or 2 billion (assuming 200 million stars in the Milky Way Galaxy).
fp = The number of stars that have planets in orbit around them. 50%, so now 1 billion candidates.
ne = Of these planets which can support life. 50%, so now 500 million.
fl = Which planets actually do support life. 20% or 100 million.
fi = Of this life what percentage is intelligent. 1% or 1 million.
fc = Of these, how many actually broadcast (have the technology to do so) the fact that they exist. 50% 0r 500,000 left.
L = The time period that this intelligent species actually broadcasts proof of its existence. That is, how long they last before they disappear/hit the little red button/melt their polar ice caps/etc. One out of 50 maybe? So 2%, that leaves us with 10,000.

Most estimates say that of the 200 million (100-400 million are the current estimates) stars in our galaxy about 10,000 of these may have civilizations orbiting around them. So that's .005% of stars. Here's the problem that most people are unaware of. The universe is an immensely empty place. The nearest star, Proxima Centauri, is 4.2 light years away. Compare that to the fact that we are a mere 8 light minutes away from the sun... 8 minutes - 4.2 years, and it has a .005% chance of having intelligent sustaining etcetera life. Not so good. So the actual odds of us coming into contact with another civilization (that still exists - as in, we're not just picking up their radio waves that are 10,000 years old) are very bleak.

Here's what the equation does tell us. Life most likely exists elsewhere and even in our galaxy in relatively great quantity. Before you go criticizing my methods consider this. This is something I learned from some great statistician who's name I don't remember (but who's work included the first investigations on the impact of climate change). It doesn't matter that these numbers aren't accurate. Ever if they're off by one hundred magnitudes that still means life exists at a rate of 100 or 1,000,000 civilizations in our galaxy. The point is that they still exist.

Our universe is comprised of matter who's interactions are governed by the four forces (gravity, electromagnetism, strong nuclear force, weak nuclear force) as we currently understand them. What I find fascinating is that due to this unique combination of rules we get everything that we see before us. Gravity determines the shape of the universe. The strong and weak nuclear forces determine the number and size of atoms that exist, and by extension all of chemistry. Therefore, it is a property of matter in the universe that we inhabit to form galaxies and solar systems with suns and planets. If the conditions are right they can sustain another possibility of matter which is life. Beyond that, this "life" (it's tricky to define if you really think about it) can become intelligent to the point that it can understand what it is made of and how it came to be so; essentially it becomes self aware in the most significant way. And if you're me then you also believe that one day humans will make machines that are capable of the same thing. So really it is a property of matter that it can quite literally understand itself.

I admit, it gets a little weird but it's fun to think about. There's plenty more to add to that.