--%>
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 Eotvos law of capillarity

    Eotvos law of capillarity (Baron L. von Eotvos; c. 1870): The surface tension gamma of a liquid is associated to its temperature T, the liquid's critical temperature, T*, and its density rho by: gamma ~=

    		•
  • Q : What is Magnetic monopole Magnetic

    Magnetic monopole: The hypothetical particle that comprises sources and sinks of the magnetic field. The magnetic monopoles have never been found, however would only cause pretty minor modifications to the Maxwell's equations. They also appear to be p

    		•
  • Q : What is Reflection law Reflection law :

    Reflection law: For a wave-front intersecting a reflecting surface, the angle of incidence is equivalent to the angle of reflection, in the similar plane stated by the ray of incidence and the normal.

    		•
  • Q : Acceleration during this interval The

    The velocity of a body was observed to be constant throughout five minutes of its motion. Determine its acceleration during this interval?

    		•
  • Q : Calculate time needed for thermocouple

    A thermocouple of K type is suddenly exposed to air with temperature of 1273K, Initial temperature was 293 K. Calculate the time needed for the thermocouple read the temperature with accuracy of better that 99%. Ignore radiation and conduction. The measuring element has a ball shape of diameter o

    		•
  • Q : Describe the term ntu in thermodynamics

    Describe the term ntu in thermodynamics? Illustrate in short.

    		•
  • Q : Define Occams razor or Ockhams razor

    Occam's [or Ockham's] razor (William of Occam [or Ockham]; c. 1340): It is the suggestion that the simpler a theory is the better. When two theories forecast the phenomena to the similar accuracy, then the one that is simpler is the better one. Furthe

    		•
  • Q : What nucleons altogether in a nucleus

    Explain what does held the nucleons altogether in a nucleus?

    		•
  • Q : Define Charles law Charles' law (J.A.C.

    Charles' law (J.A.C. Charles; c. 1787): The volume of an ideal gas at constant (steady) pressure is proportional to the thermodynamic temperature of that gas.

    		•
  • 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

    		•