Sunday, 12 July 2009

Life Away From Earth??

Hello Reader,

do you think there really is life out there? Did Roswell actually happen? Or are you on the other end of the spectrum, no life other than terrestrial being? Well today we will explore the mathematics of extra-terrestrials!


That’s right, math that predicts the probability of other aliens.


The equation is called the Drake Equation. This equation was brought about by Dr. Frank Drake of University of California who is a scientist in Astronomy and Astrophysics.


Not only does the equation predict how many civilizations are out there, it also predicts advanced civilizations! How many are at our level of intelligence and beyond. Without further ado, here is the ever so famous equation:


N = R x P x Ne x L x I x FC x LT


What do all these wonderful letters mean?


  • N is the number of aliens that possible could contact us or visa versa.
  • R is the average star formation
  • P is the fraction of stars that have planets surrounding it
  • Ne is the number of planets that could support life for every star that has a planet
  • L is the fraction of planets that WILL have life on it... at one point. Because everything started off as a single celled organism, this is going to be higher than N
  • I is the fraction of l that will become intelligent life. This could be an animal (anything that has a structure like our neural system).
  • FC is the fraction of intelligent life that can and will build a detection device for communication purposes.
  • LT is the time length in which a signal will be sent.


Here are values that have been used with this equation (taken from Wikipedia):


  • R = 10/year the Milky Way averages 10 stars per years.
  • P = 0.5 about half these stars will develop/pull planets into its orbit.
  • NE = 2 scientists believe that 2 of these planets will be able to support life.
  • Recap so far: 10 stars, 5 stars with planets 2 of these will have planets that support life.
  • L = 1 (100% of these planets will develop life of any kind. Such as microbes or amoebas.) (I would think only 50% at most but let’s go with this)
  • I = 0.01 (1% that could be intelligent)
  • FC = 0.01 (1% that could communicate with us.)
  • LT = 10,000 years (how long the civilization will last 10,000 years)


If we multiply each of these numbers together, we get N = 10 alien beings that we COULD encounter. This is only theoretical and we still have yet to encounter any (except possibly at Roswell).


If we use my 50% instead of the 100% for the ‘L’ value we come up with 5. This seems more reasonable. Makes sense why we have yet to encounter anything in this vast galaxy.


That concludes Drake’s equation. As always, comments are always excepted and topic suggestions are welcome as well.


Thanks for reading Keith’s Mind.

5 comments:

Jonathan said...

You forgot 'B'-- The amount of bullshit you're willing to buy from Drake, hehe.

A conservative calculation of the Drake equation gives the answer 1 (Kurzweil mentions this in 'Singularity'), and I think we've already discovered who they are.

Jonathan said...

Allow me to quote the variables, as assumed by Kurzweil:
-50% of stars have planets
-10% of planets can sustain life
-1% of these planets have evolved life
-5% of evolved creatures have developed sentience
-50% of sentient creatures are radio-capable
-Aaaand that the average radio-capable civilization has been broadcasting for the last ten thousand years (=10^-6)...

That gives the answer 1.25, or roughly 1.

Carl Sagan himself estimated that the number if around a million, and Drake himself estimated ten thousand [these are properly cited by Kurzweil].

Keith said...

But really, how do we know that Kruzweil is correct? As for Drake's estimate, the values used were his colleague's and his estimate in 1961. Yes, we have more sophisticated technology to determine better estimates.
Here are some recent estimates:
7 stars/year
30%-50% of these have planets
2 planets that COULD possibly sustain life
0.5 that will go on to develop life.
About 1% will be intelligent life.
Another 1% to be able to communicate.
And civilizations last an average of 6,000 years. That's how long humans have "communicated" on Earth.
This give us 1.68. Rounded that's 2.

Jonathan said...

That's one problem with th'man: He tends to cheat. As PZ Myers noted, Kurzweil's numbers can be a bit off, especially when he's got a purpose in mind.

All the more reason to be a critical reader, hehe. As Twain said- "There are lies, damned lies, and statistics."

JPoisson said...

well aside from your guys dispute, Nice article Keith, I am a firm believe that their could be other life somewhere.

Although the formula seems like it could be realistic I am not sure though that N is being represented properly.

it shouldn't be for the individual aliens. It should be for their society, so instead of 1.3 aliens contacting us it should be 1.3 alien society's.