--%>
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 Schwarzschild radius

    Schwarzschild radius: The radius ‘r’ of the event horizon for a Schwarzschild black hole of mass m is specified by (in geometrized units) r = 2 m. In its conventional units: r = 2 G m/c2

    		•
  • Q : Define Volt or SI unit of electric

    Volt: V (after A. Volta, 1745-1827): The derived SI unit of electric potential, stated as the difference of potential among the two points on a conductor fetching  a constant current of 1 A whenever the power dissipated between the points is 1 W;

    		•
  • Q : What is curvilinear motion What do you

    What do you mean by the term curvilinear motion? State in brief?

    		•
  • Q : Explain Uncertainty principle

    Uncertainty principle (W. Heisenberg; 1927): A principle, central to the quantum mechanics that states which two complementary parameters (like energy and time, position and momentum, or angular momentum and angular displacement) can’t both be r

    		•
  • Q : Explain Bohr magneton and Bohr radius

    Bohr magneton (N. Bohr) - This is the quantum of magnetic moment. Bohr radius (N. Bohr) - The distance equivalent to the mean distance of an electron from the nucleus in the ground state of hydroge

    		•
  • 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 : What is Eotvos law of capillarity

    Eotvos law of capillarity (Baron L. von Eotvos; c. 1870): The surface tension gamma of a liquid is associated to its temperature T, the liquid's critical temperature, T*, and its density rho by: gamma ~=

    		•
  • 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 : Explain Curie-Weiss law Curie-Weiss law

    Curie-Weiss law (P. Curie, P.-E. Weiss): A more broad form of Curie's law that states that the susceptibility, khi, of a paramagnetic substance is associated to its thermodynamic temperature T by the equation:

    Q : Define Fermi paradox Fermi paradox (E.

    Fermi paradox (E. Fermi): E. Fermi's inference, simplified with the phrase, "Where are they?" questioning that when the Galaxy is filled with intelligent and scientific civilizations, why haven't they come to us hitherto? There are nu

    		•