--%>
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 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

    		•
  • Q : What is Boltzmann constant Boltzmann

    Boltzmann constant: k (L. Boltzmann) - The constant that explains the relationship between kinetic energy and temperature for molecules in an ideal gas. This is equivalent to the 1.380 622 x 10-23 J/K.

    		•
  • Q : Describe the term Specular Reflection

    Describe briefly the term Specular Reflection?

    		•
  • 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 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 : Rest mass energy of the electron What

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

    		•
  • Q : When the intermolecular forces are

    Describe when the intermolecular forces are strongest? Briefly state it.

    		•
  • Q : What is Wiens displacement law constant

    Wien's displacement law constant, b: It is the constant of Wien displacement law. This has the value of 2.897 756 x 10-3 m K.

    		•
  • Q : What is Maxwells demon Maxwell's demon

    Maxwell's demon (J.C. Maxwell): A contemplation experiment describing the concepts of entropy. We contain a container of gas that is partitioned into two equivalent sides; each side is in thermal equilibrium with the other. The walls and the separatio

    		•
  • Q : Explain Twin paradox Twin paradox: One

    Twin paradox: One of the most well-known "paradoxes" in history, predicted by Sir Einstein's special theory of relativity. It takes two twins, born on similar date on Earth. One, Albert, leaves home for a trip about the Universe at very high speeds (v

    		•