--%>
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 Equivalence principle

    Equivalence principle: The fundamental postulate of Sir Einstein’s general theory of relativity that posits that acceleration is basically indistinguishable from the gravitational field. In another words, when you are in an elevator that is utte

    		•
  • Q : Describe the term Specular Reflection

    Describe briefly the term Specular Reflection?

    		•
  • Q : Information in physics What do you mean

    What do you mean by the term information in physics?

    		•
  • Q : Explain Newtons law of universal

    Newton's law of universal gravitation (Sir I. Newton): Two bodies exert a pull on each other with equivalent and opposite forces; the magnitude of this force is proportional to the product result of the two masses and is too proportional to the invers

    		•
  • 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 : Problem on magnetically coupled pair

    When one coil of a magnetically coupled pair has a current of 5.0A, the resulting fluxes Φ11 and Φ21 are 0.2mWb and 0.4mWb, respectively.  If the turns are N1 = 500 and N2 = 1500, find L1, L2, M and the coeffici

    		•
  • Q : Motion balance principle Explain in

    Explain in detail the motion balance principle

    		•
  • Q : Define Faint Faint , young sun paradox

    Faint, young sun paradox: The theories of stellar evolution point out that as stars mature on the main series, they grow gradually hotter and brighter; computations propose that at as regards the time of the formation of Earth, the Su

    		•
  • Q : Explain Tachyon paradox Tachyon

    Tachyon paradox: The argument explaining that tachyons (should they subsist, of course) can’t carry an electric charge. For an imaginary-massed particle travelling faster than c, less energy the tachyon has, the faster it travels, till at zero e

    		•
  • Q : Define Joule or SI unit of energy Joule

    Joule: J (after J.P. Joule, 1818-1889): The derived SI unit of energy stated as the quantity of work done by moving an object via a distance of 1 m by exerting a force of 1 N; it therefore has units of N m.

    		•