--%>
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 Steradian or SI unit of solid

    Steradian: sr: The supplementary SI unit of solid angle stated as the solid central angle of a sphere which encloses a surface on the sphere equivalent to the square of the sphere's radius.

    		•
  • Q : Radar gun problem Whenever a radar gun

    Whenever a radar gun states the pitch is 90 miles per hour at what point in the balls travel to home plate is the radar gun evaluating the velocity?

    		•
  • Q : What is Super fluidity Super fluidity :

    Super fluidity: The phenomenon by which, at adequately low temperatures, a fluid can flow with zero (0) viscosity. These causes are related with the superconductivity.

    		•
  • Q : Explain Photoelectric effect

    Photoelectric effect: An effect described by A. Einstein that demonstrates that light seems to be made up of particles, or photons. The light can excite electrons (termed as photoelectrons in this context) to be ejected from the metal. Light with a fr

    		•
  • Q : Define Mach number Mach number (E.

    Mach number (E. Mach): It is the ratio of the speed of an object in a specified medium to the speed of sound in that medium.

    		•
  • 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 : What is Simultaneity principle

    Simultaneity principle: The principle which all frames of reference will contain invariant simultaneity; that is, the two events perceived as simultaneous (that is, containing the similar time coordinate) in one frame will be apparent as simultaneous

    		•
  • 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 Second or SI unit of time

    Second: s: The basic SI unit of time, stated as the period of time equivalent to the duration of 9 192 631 770 periods of the radiation analogous to the transition between the two hyperfine levels of the ground state of cesium-133 atom.

    		•
  • Q : Define Constancy principle Constancy

    Constancy principle (A. Einstein): One of the postulates of Sir Einstein's special theory of relativity that puts forth that the speed of light in vacuum is computed as similar speed to all observers, in spite of of their relative mot

    		•