--%>
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 : Define Ideal gas constant or universal

    Define Ideal gas constant or universal molar gas constant? Ideal gas constant: or universal molar gas constant; R: The constant which appears in the ideal gas equation. It is equivalent to

    		•
  • Q : What is Kirchhoffs law of radiation

    Kirchhoff's law of radiation (G.R. Kirchhoff): The emissivity of a body is equivalent to its absorbptance at similar temperature.

    		•
  • Q : Characteristics of electronics what is

    what is the characteristics of electronics ?

    		•
  • 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 : Define Universal constant of gravitation

    Universal constant of gravitation: G The constant of proportionality in the Newton’s law of universal gravitation and that plays a comparable role in Sir Einstein's general relativity. This is equivalent to the 6.672 x 10-1

    		•
  • Q : Define Hubbles law Hubble's law (E.P.

    Hubble's law (E.P. Hubble; 1925): The relationship discovered between radial velocity and distance. The further away a galaxy is away from is, the quicker it is receding away from us. The constant of proportionality is the Hubble cons

    		•
  • 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 : Motion balance principle Explain in

    Explain in detail the motion balance principle

    		•
  • 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 : Problem on Adiabatic law When air is

    When air is compressed adiabatically the law connecting the absolute temperature T and the pressure P is of the form T = A.Pn where A and N are constants. Show by drawing a suitable linear graph that the experimental dat

    		•