--%>
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 : What is Permeability of free space or

    Permeability of free space: magnetic constant: mu_0: The ratio of the magnetic flux density in the substance to the external field strength for vacuum. It is equivalent to 4 pi x 10-7 H/m.

    		•
  • Q : Plasma globe AD advantages and

    advantages and disadvantages of a plasma globe

    		•
  • Q : Explain the procedure to compute the

    Briefly explain the procedure to compute the tensile strength?

    		•
  • Q : Define Ohm or SI unit of electric

    Ohm: Omega: O (after G. Ohm, 1787-1854) The derived SI unit of electric resistance, stated as the resistance among two points on a conductor whenever a constant potential difference of 1 V generates a current of 1 A in the conductor;

    		•
  • Q : Physics Assignement complete assignment

    complete assignment with clear solution and explanation

    		•
  • Q : Define Steradian or SI unit of solid

    Steradian: sr: The supplementary SI unit of solid angle stated as the solid central angle of a sphere which encloses a surface on the sphere equivalent to the square of the sphere's radius.

    		•
  • Q : Define Machs principle Mach's principle

    Mach's principle (E. Mach; c. 1870): The inertia of any specific particle or particles of matter is attributable to the interaction among that piece of matter and the rest of the world. Therefore, a body in isolation would contain no inertia.

    		•
  • Q : Continuity of equation or Equation of

    Define Equation of continuity or Continuity of equation: An equation that states that a fluid flowing via a pipe flows at a rate that is inversely proportional to the cross-sectional region of the pipe. That is, when the pipe constric

    		•
  • Q : Define Hertz or SI unit of frequency

    Define Hertz or SI unit of frequency: Hertz: Hz (after H. Hertz, 1857-1894): The derived SI unit of frequency, stated as a frequency of 1 cycle per s; it therefore has units of s-1.

    		•
  • Q : Define Tesla or SI unit of the magnetic

    Tesla: T (after N. Tesla, 1870-1943): The derived SI unit of the magnetic flux density stated as the magnetic flux density of a magnetic flux of 1 Wb via an area of 1 m2; it therefore has units of Wb/m2.

    		•