--%>
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 : Becquerel Becquerel : Bq (after A.H.

    Becquerel: Bq (after A.H. Becquerel, 1852-1908) - The derived SI unit of the activity stated as the activity of radionuclide decay at a rate, on the average, of one nuclear transition every 1 s; it hence has units of s-1.

    		•
  • Q : Explain the procedure to compute the

    Briefly explain the procedure to compute the tensile strength?

    		•
  • Q : Define Lux or SI unit of the illuminance

    Lux: lx: The derived SI unit of the illuminance equivalent to the illuminance generated by a luminous flux of 1 lm distributed consistently over a region of 1 m2; it therefore has units of lm/m2.

    		•
  • Q : Define Stefan-Boltzmann constant

    Stefan-Boltzmann constant: sigma (Stefan, L. Boltzmann): The constant of proportionality exist in the Stefan-Boltzmann law. It is equivalent to 5.6697 x 10-8 W/m2/K4.

    		•
  • Q : Problem on Adiabatic law When air is

    When air is compressed adiabatically the law connecting the absolute temperature T and the pressure P is of the form T = A.Pn where A and N are constants. Show by drawing a suitable linear graph that the experimental dat

    		•
  • Q : Formula for acceleration What is the

    What is the appropriate formula employed to compute the acceleration? Explain in brief.

    		•
  • Q : Energy and light My question is Eph =

    My question is Eph = hcT. I have to rearrange the equation to make b b the subject and also find the SI units for b and how and why they are those units.....

    		•
  • Q : Explain Pascals principle Pascal's

    Pascal's principle: The pressure exerted to an enclosed incompressible static fluid is transmitted undiminished to all portions of the fluid.

    		•
  • Q : Define Rydberg constant Rydberg

    Rydberg constant (Rydberg): The constant that governs the relationship of the spectral line features of an atom via the Rydberg formula. For hydrogen, it is around 1.097 x 107 m-1.

    		•
  • Q : Definition of Pascals principle Briefly

    Briefly state the definition of Pascal’s principle?

    		•