SETI

What is the Drake equation? Why do scientists look at the "waterhole" for potential signals from extraterrestrials? The Drake Equation can determine how many possible intelligent, communicating civilizations there are in our galaxy. It was developed in 1961 by Dr. Frank Drake. it is expressed as: Nc = N* fp ne fl fi fc fL The equation represents the following: N* represents the number of stars in the Milky Way Galaxy fp is the fraction of stars that have planets around them ne number of planets per star that are capable of sustaining life fl is the fraction of planets in ne where life evolves fi is the fraction of fl where intelligent life evolves fc is the fraction of fi that communicate fL is fraction of the planet's life during which the communicating civilizations may survive When all of these variables are multiplied, we get: Nc, the number of communicating civilizations in the galaxy. water hole, refers to an especially quiet band of the electromagnetic spectrum between 1,420 and 1,666 megahertz, corresponding to wavelengths of 21 and 18 centimeters respectively. Water is thought to be essential to extraterrestrial life. This is the reason why scientists are looking for these waterhole.  source wikipedia