--%>
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 : Describe Wien displacement law Wien

    Wien displacement law: For a blackbody, the product result of the wavelength corresponding to the maximum radiances and the thermodynamic temperature is constant, then the Wien displacement law constant. As an outcome, as the temperature increases, th

    		•
  • Q : Explain Davisson-Germer experiment

    Davisson-Germer experiment (C.J. Davisson, L.H. Germer; 1927): The experiment which conclusively proved the wave nature of electrons; diffraction patterns were examined by an electron beam penetrating into the nickel target.

    		•
  • Q : Define Tipler machine Tipler machine:

    Tipler machine: The solution to Einstein's equations of general relativity which permits time travel. A tremendously dense (that is, on the order of the density of neutron star matter), infinitely-long cylinder that rotates very quickly can form close

    		•
  • Q : Calculate time needed for thermocouple

    A thermocouple of K type is suddenly exposed to air with temperature of 1273K, Initial temperature was 293 K. Calculate the time needed for the thermocouple read the temperature with accuracy of better that 99%. Ignore radiation and conduction. The measuring element has a ball shape of diameter o

    		•
  • Q : Why sun emerge flat throughout sunrise

    Briefly explain the reason why does sun emerge flat throughout sunrise and sunset?

    		•
  • Q : Elementary particles concepts Write

    Write down any two elementary particles that have nearly infinite life time?

    		•
  • Q : Conservation laws and illustrations of

    Explain Conservation laws and illustrations of conservation laws (Conservation of mass-energy, electric charge, linear momentum and angular momentum) ? Conservation laws: The law which states that,

    		•
  • Q : Define Parsec Parsec : The unit of

    Parsec: The unit of distance stated as the distance pointed by an Earth-orbit parallax of 1 arcsec. It equals around 206 264 au, or about 3.086 x 1016 m

    		•
  • Q : Explain Coanda effect Coanda effect:

    Coanda effect: The effect which points out that a fluid tends to flow all along a surface, instead of flowing via free space.

    		•
  • Q : What is Laplace equation Laplace

    Laplace equation (P. Laplace): For the steady-state heat conduction in 1-dimension, the temperature distribution is the explanation to Laplace's equation, which defines that the second derivative of temperature with respect to displac

    		•