--%>
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 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 : Define Josephson effects Josephson

    Josephson effects (B.D. Josephson; 1962): Electrical effects examined whenever two superconducting materials are separated by a thin layer of the insulating substance.

    		•
  • Q : What is Cherenkov radiation Cherenkov

    Cherenkov radiation (P.A. Cherenkov): The radiation emitted by a huge particle which is moving faster than light in the medium via which it is travelling. No particle can travel faster than the light in vacuum, however the speed of light in other medi

    		•
  • Q : Define Luxon Luxon : The particle that

    Luxon: The particle that travels solely at c (that is the speed of light in vacuum). All luxons have a rest mass of exactly zero. Though they are mass less, luxons do take momentum. The photons are the prime illustration of luxons (that is the name it

    		•
  • Q : Fundamental principles of the regulation

    Describe the fundamental principles of the regulation? Briefly describe the principles?

    		•
  • Q : Explain Boyle's law Boyle's law (R.

    Boyle's law (R. Boyle; 1662); Mariotte's law (E. Mariotte; 1676) - The product result of the volume and pressure of an ideal gas at constant (steady) temperature is constant.

    		•
  • Q : Define Cosmological redshift

    Cosmological redshift: The effect where light emanates from a distant source appears redshifted since of the expansion of the space time itself.

    		•
  • Q : Features or characteristics of dead

    Write a short note on the features or characteristics of dead stars?

    		•
  • Q : Define Fermats principle Fermat's

    Fermat's principle: principle of least time (P. de Fermat): The principle, put onward by P. de Fermat that explains the path taken by a ray of light among any two points in a system is for all time the path which takes the least time.

    		•
  • Q : What do you mean by the term cardiac

    What do you mean by the term cardiac output? Briefly explain it.

    		•