--%>
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 : What is Wave-particle duality

    Wave-particle duality: The principle of quantum mechanics that entails that light (and, certainly, all other subatomic particles) at times act similar to a wave, and sometime act similar to a particle, based on the experiment you are executing. For ex

    		•
  • Q : Explain Millikan oil drop experiment

    Millikan oil drop experiment (R.A. Millikan): A famed experiment designed to compute the electronic charge. The drops of oil were carried past a consistent electric field among charged plates. Subsequent to charging the drop with x-ra

    		•
  • 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 : Rest mass energy of the electron What

    What do you mean by the rest mass energy of the electron?

    		•
  • Q : Explain avogadro's hypothesis

    Avogadro's hypothesis (Count A. Avogadro; 1811): Equivalent volumes of all gases at similar temperature and pressure contain equivalent numbers of molecules. This is, in fact, true only for the ideal gases.  <

    		•
  • Q : Define Permittivity of free space or

    Permittivity of free space: electric constant; epsilon_0: The ratio of the electric displacement to the intensity of the electric field generating it in vacuum. It is equivalent to 8.854 x 10-12 F/m.

    		•
  • 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 : Dynamic strain aging and the strain

    What is the basic difference among the dynamic strain aging and the strain aging?

    		•
  • Q : Explain Coanda effect Coanda effect:

    Coanda effect: The effect which points out that a fluid tends to flow all along a surface, instead of flowing via free space.

    		•
  • 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.

    		•