Tuesday, August 01, 2006

Extension to the Drake Equation

N=N* Fp Ne F1 Fi Fc FL

N*- Number of stars in the galaxy
Fp- Fractions of stars with planets.
Ne- Number of planets per star capable of life
F1- Fraction of those planets where life actually evolves.
Fi- Fraction of those where life is intelligent.
Fc- Fraction of those that can communicate
Fl- Fraction of their planet’s life where the civilization lives.

To those who are familiar with SETI or any area of cosmology concerned with the existence of life on other planets, the above equation should look pretty familiar. It’s known as the Drake Equation.

Named after a certified smarty-pants, Frank Drake, the equation was first written out in 1961, by, whom else, Frank Drake. It’s concerned with trying to figure out how many intelligent, suitably advanced civilizations exist in our galaxy and, by extension, the known universe.

I think there is an important extension that should be applied to the equation, one that is important if this equation is to have any real ramifications on how we engage in science related to extraterrestrial life. Namely, even if they’re out there, can we see them? I don’t know if there have been any papers that have already addressed this topic, and any of you know of one, please send me a reference.

In many ways, this goes back to my earlier post about our entire modern civilization being the product of just one human lifetime. We have been around for such a spectacularly short amount of time, even if you include all of our evolutionary ancestors, that we have actually achieved very little. We’ve only just begun, as it were.

If we expand our personal scale to a cosmological scale, we are nonexistent. Our great civilization is nothing. If we again take the number of 5,000 years as a good number to describe the age of our civilization, and we then take the age of the universe to be 13 billion years, we are less than one half of one percent of one percent of one percent of the universe’s timeline. 0.0001%.

I don’t mean to sound like I’m bashing the human race. I’m really amazed with the amount of progress we’ve made in such a short time. Especially in the last one hundred or so years our civilization has exploded with innovation and advancement. We haven’t even been using radio waves for a full human lifetime.

We can barely imagine where we will be 100, 200 years in the future. Just look at Star Trek. With every variant of the show to come out, their technology gets more incredible. Aside from the interstellar travel and transporter that are hallmarks of the series, we have all the goodies they had in the first series. We’re advancing so fast, our story tellers can’t keep up.

I think it would be arrogant to think we would be unique in our speedy advancement. So imagine a race, equally driven, that had a two million year head start. Actually, don’t bother, because I don’t think we can. In fact, they would have been beyond our imagination for the vast majority of the history of their species.

Because a race in our stage of advancement takes up such a tiny amount of cosmological time, sheer statistics dictates that we are most likely to discover a race that is still at chimp-level, or beyond our wildest imagination.

Because of this, I consider it downright absurd to think that a race that advanced is using something as ancient as radio waves. The speed of light is just so passé. We’re already touching upon the edges of discovery with postulated gravity waves and entangled particles. We may not even use radio in a hundred years.

So assume a communication medium that’s beyond our ability to detect, which, again, makes up the vast majority of this species’ history. Statistics again says that any radio waves emanated by this civilization are either way far away, or have long passed us by. We’re looking for something that, even if we assume the existence of other species, is so improbable as to be useless to seek. We’re effectively sitting in the dark, hoping that the little spurt of radio waves emitted by a civilization thousands/millions of years ago just happens to pass us by.

In this case, it’s not a question of whether they have the ability to transmit, Fc, but whether we have the ability to receive.

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