--%>
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 Machs principle Mach's principle

    Mach's principle (E. Mach; c. 1870): The inertia of any specific particle or particles of matter is attributable to the interaction among that piece of matter and the rest of the world. Therefore, a body in isolation would contain no inertia.

    		•
  • Q : Explain Tachyon paradox Tachyon

    Tachyon paradox: The argument explaining that tachyons (should they subsist, of course) can’t carry an electric charge. For an imaginary-massed particle travelling faster than c, less energy the tachyon has, the faster it travels, till at zero e

    		•
  • Q : Define Le Chateliers principle Le

    Le Chatelier's principle (H. Le Chatelier; 1888): When a system is in equilibrium, then any modification imposed on the system tends to shift the equilibrium state to decrease the consequence of that applied change.

    		•
  • Q : Define Newton or SI unit of force

    Newton: N (after Sir I. Newton, 1642-1727): The derived SI unit of force, stated as the force needed to give a mass of 1 kg of an acceleration of 1 m/s2; it therefore has units of kg m/s2.

    		•
  • Q : Describe Solar water heating Solar

    Solar water heating: Solar water heaters are simple, reliable, famous and widespread. They are probably the Low Carbon technology closest to being commercially practised. The most efficient designs concentrate solar radiation onto a small diameter tub

    		•
  • Q : Explain Stern-Gerlach experiment

    Stern-Gerlach experiment (O. Stern, W. Gerlach; 1922): The experiment which explains the features of spin (that is intrinsic angular momentum) as a different entity apart from the orbital angular momentum.

    		•
  • Q : What is De Broglie wavelength De

    De Broglie wavelength (L. de Broglie; 1924): The prediction that particles too contain wave characteristics, where the efficient wavelength of the particle would be inversely proportional to its momentum, where the constant of the pro

    		•
  • Q : Define Centrifugal pseudo force

    Centrifugal pseudo force: A pseudo force which takes place whenever one is moving in uniform circular motion. One feels a "force" directed outward from the center of the motion.

    		•
  • Q : Define Determinism principle

    Determinism principle: The principle that when one knows the state to an unlimited accuracy of a system at one point in time, one would be capable to predict the state of that system with unlimited accuracy at any other time, past or the future. For i

    		•
  • 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.

    		•