--%>
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 : Explain Youngs experiment or

    Young's experiment: double-slit experiment (T. Young; 1801): A well-known experiment that exhibits the wave nature of light (and certainly of other particles). The light is passed from a small source into an opaque screen with the two thin slits. The

    		•
  • Q : State Kohlrauschs law Kohlrausch's law

    Kohlrausch's law (F. Kohlrausch): When a salt is dissolved in water, the conductivity of the solution is the addition of two values -- one depending on the positive ions and the other on negative ions.

    		•
  • Q : Explain Bohr magneton and Bohr radius

    Bohr magneton (N. Bohr) - This is the quantum of magnetic moment. Bohr radius (N. Bohr) - The distance equivalent to the mean distance of an electron from the nucleus in the ground state of hydroge

    		•
  • Q : Explain Ideal gas equation Ideal gas

    Ideal gas equation: The equation that sums up the ideal gas laws in one simple equation, P V = n R T, Here V is the volume, P is the pressure, n is the

    		•
  • Q : Problem on spacecraft Assuming that

    Assuming that ground stations are equally distributed on the Earth, how many ground stations are required to maintain constant contact with a spacecraft at 750 km altitude, and 72 degrees inclination?

    		•
  • Q : Define Henry or SI unit of inductance

    Henry: H (after W. Henry, 1775-1836): The derived SI unit of inductance, stated as the inductance of a closed circuit in which the electromotive force of 1 V is generated whenever the electric current differs uniformly at a rate of 1

    		•
  • Q : Define Systeme Internationale d'Unites

    Systeme Internationale d'Unites (SI): The rationalized and coherent system of units derived from the m.k.s. system (that itself is derived from metric system) in common utilization in physics nowadays.

    		•
  • Q : Solution Of Laplace’s Equation 1. Solve

    1. Solve Laplace's equation for the electrical potential between two infinite parallel plates, which have a charge density per unit area -on one plate and a charge density per unit area -! on the second plate, and determine the electric field between the plates from t

    		•
  • Q : Define Rayleigh criterion or resolving

    Rayleigh criterion: resolving power: The criterion for determining how delicately a set of optics might be able to differentiate. This  starts with the supposition that central ring of one image must fall on the first dark ring of the other; for

    		•
  • Q : Explain Gauss law for magnetic fields

    Gauss' law for magnetic fields (K.F. Gauss): The magnetic flux via a closed surface is zero (0); no magnetic charges present; in its differential form, div B = 0

    		•