--%>
Assignment Help - homework help

Explain Drake equation

Drake equation (F. Drake; 1961): The method of estimating the number of intelligent, scientific species (that is, able to communicate with other species) in subsistence in our space.

N = R fp ne fl fi ft L.

Here,

N is the number of species explained above at any specified moment in our Galaxy. The parameters it is evaluated from are as follows:

R = the rate of star formation in our solar system (in stars per year);
fp = the fraction of stars that contain planets;
ne = the total number of habitable planets per system with planets;
fl = the fraction of habitable planets on which the life arises;
fi = the fraction of such planets on which the life develops intelligence;
ft = the fraction of such planets where the intelligence grows into a technological civilization which is capable of communication; and
L = the mean life-time of such a scientific civilization.

Out of these quantities, only the first -- R -- is recognized with anything like any reliability; this is on the order of 10 stars per year. The others, most particularly the fractions, are approximately totally pure speculation at this point. Computations made by respectable astronomers vary by something like ten orders of magnitude in the last estimation of the number of species out there.

   Related Questions in Physics

  • Q : Dynamic strain aging and the strain

    What is the basic difference among the dynamic strain aging and the strain aging?

    		•
  • Q : Information in physics What do you mean

    What do you mean by the term information in physics?

    		•
  • Q : Define Brackett series Brackett series

    Brackett series (Brackett) - The series (or sequence) that explains the emission spectrum of hydrogen whenever the electron is jumping to fourth orbital. All of the lines are in the infrared segment of the spectrum.

    		•
  • Q : What is Wave-particle duality

    Wave-particle duality: The principle of quantum mechanics that entails that light (and, certainly, all other subatomic particles) at times act similar to a wave, and sometime act similar to a particle, based on the experiment you are executing. For ex

    		•
  • Q : Define Olbers paradox Olbers' paradox

    Olbers' paradox (H. Olbers; 1826): If the Universe is infinite, consistent, and unchanging then the whole sky at night would be bright -- concerning as bright as the Sun. The further you stared out into space, the more stars there would be, and theref

    		•
  • Q : Define Dirac constant Dirac constant :

    Dirac constant: Planck constant, modified form; hbar Sometimes more suitable form of the Planck constant, stated as: hbar = h/(2 pi)

    		•
  • Q : What is Peltier effect Peltier effect

    Peltier effect (J.C.A. Peltier; 1834): The modification in temperature produced at a junction among the two dissimilar metals or semiconductors whenever an electric current passes through the junction.

    		•
  • Q : Brewster's law Brewster's law (D.

    Brewster's law (D. Brewster) - The extent or level of the polarization of light reflected from a transparent surface is maximum whenever the reflected ray is at right angle to the refracted ray.  

    		•
  • Q : Universal law of universal gravitation

    Describe the universal law of universal gravitation? Briefly describe it.

    		•
  • Q : Problem on two coupled coils connected

    In a series adding connection, two coupled coils have equivalent inductances LA; in a series opposing connection, LB. Determine an expression for M in terms of LA and LB. What does the outcome suggest?

    		•