--%>
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 : Fission and Fusion What do you mean by

    What do you mean by Fission and Fusion?

    		•
  • Q : Define Kilogram or SI unit of mass

    Kilogram: kg: The basic SI unit of mass that is the only SI unit still maintained by a physical artifact: a platinum-iridium bar reserved in the International Bureau of Weights and Measures at Sevres, France.

    		•
  • 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 : How radiation emitted from the body

    Describe the procedure how radiation emitted from the body? Illustrate in brief.

    		•
  • Q : Kirchhoffs rules or Loop rule or Point

    Explain Kirchhoff's rules or Kirchhoff's Loop rule and Point rule? Kirchhoff's rules (G.R. Kirchhoff) <

    		•
  • Q : Define Relativity principle Relativity

    Relativity principle: The principle, utilized by Einstein's relativity theories, that the laws of physics are similar, at least qualitatively, in all frames. That is, there is no frame which is better (or qualitatively any different) from any other. T

    		•
  • Q : How energy transformed in windmills

    Explain how is energy transformed in the windmills?

    		•
  • Q : What is Hooke law Hooke's law (R.

    Hooke's law (R. Hooke): The stress exerted to any solid is proportional to the strain it generates within the elastic limit for that solid. The constant of that proportionality is the Young modulus of elasticity for that material.

    		•
  • Q : Velocity of the particle Determine the

    Determine the Velocity of the particle in terms of component veocities?

    		•
  • Q : What is Lyman series Lyman series: The

    Lyman series: The sequence that explains the emission spectrum of hydrogen whenever electrons are jumping to the ground state. Each and every line is in the ultraviolet.

    		•