--%>
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 : Polar Materials The molecules of many

    The molecules of many dielectrics possess an electric dipole moment without having an external electric field. In such molecules centres of their positive and negative charges are displaced with respect to each other and therefore form a dipole. Such materials are kno

    		•
  • Q : Define Pauli Exclusion Principle Pauli

    Pauli Exclusion Principle (W. Pauli; 1925): No two similar fermions in a system, like electrons in an atom, can contain an identical set of the quantum numbers.

    		•
  • Q : Explain Hawking radiation Hawking

    Hawking radiation (S.W. Hawking; 1973): The theory which black holes emit radiation similar to any other hot body. The virtual particle-antiparticle pairs are continuously being made in supposedly empty space. Infrequently, a pair wil

    		•
  • Q : Blackbody radiation What is Blackbody

    What is Blackbody radiation - The radiation - that is the radiance at specific frequencies all across the spectrum -- generated by a blackbody -- which is, a perfect radiator and absorber of the heat. Physicists had complexity exp

    		•
  • Q : Explain Youngs experiment or

    Young's experiment: double-slit experiment (T. Young; 1801): A well-known experiment that exhibits the wave nature of light (and certainly of other particles). The light is passed from a small source into an opaque screen with the two thin slits. The

    		•
  • Q : Explain Twin paradox Twin paradox: One

    Twin paradox: One of the most well-known "paradoxes" in history, predicted by Sir Einstein's special theory of relativity. It takes two twins, born on similar date on Earth. One, Albert, leaves home for a trip about the Universe at very high speeds (v

    		•
  • Q : Define Heat pumps Heat pumps move heat

    Heat pumps move heat from one place to another. They work similar to refrigeration. The movement of heat takes energy, either electrical energy as in the use of  vapor compression heat pumps or thermal energy as in the use of absorption heat pump

    		•
  • Q : Procedure to define the Specific Gravity

    Briefly explain the procedure to define the Specific Gravity?

    		•
  • Q : Explain Faradays law Faraday's law (M.

    Faraday's law (M. Faraday): The line integral of the electric field about a closed curve is proportional to the instant time rate of change of the magnetic flux via a surface bounded by that closed curve; in the differential form,

    		•
  • Q : What MeV in MeV photon signify What

    What does MeV in MeV photon signify? Briefly describe it.

    		•