--%>
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 Hertz or SI unit of frequency

    Define Hertz or SI unit of frequency: Hertz: Hz (after H. Hertz, 1857-1894): The derived SI unit of frequency, stated as a frequency of 1 cycle per s; it therefore has units of s-1.

    		•
  • Q : Ampere's law Explain  Ampere's law?  

    Explain Ampere's law?   Ampere's law (A.M. Ampere):

  • Q : Explain Archimedes' principle What is 

    What is Archimedes' principle? A body which is submerged in a fluid is buoyed up by a force equivalent in magnitude to the weight of the fluid which is displaced, and directed upward all along a line via the c

    		•
  • Q : Problem on magnetically coupled pair

    When one coil of a magnetically coupled pair has a current of 5.0A, the resulting fluxes Φ11 and Φ21 are 0.2mWb and 0.4mWb, respectively.  If the turns are N1 = 500 and N2 = 1500, find L1, L2, M and the coeffici

    		•
  • Q : Concept of nuclear reaction Describe in

    Describe in brief the concept of nuclear reaction?

    		•
  • Q : Problem on beam For the beam

    For the beam illustrated below, we require to determine: (A) the support reactions

    		•
  • Q : Define Landauers principle Landauer's

    Landauer's principle: The principle which defines that it doesn't explicitly take energy to calculate data, however instead it takes energy to remove any data, as erasure is a vital step in computation.

    		•
  • Q : What is Bode's law Bode's law :

    Bode's law: Titius-Bode law - The mathematical formula that generates, with a fair quantity of accuracy, the semi major axes of the planets in out of order from the Sun. Write down the progression 0, 3, 6, 12, 24,

    		•
  • Q : What is Magnus effect Magnus effect :

    Magnus effect: The rotating cylinder in a moving fluid drags a few of the fluid about with it, in its direction of rotation. This raises the speed in that area, and therefore the pressure is lower. Therefore, there is a total force on the cylinder in

    		•
  • Q : Explain Cosmological constant

    Cosmological constant (Lambda): The constant mentioned to the Einstein field equation, proposed to admit the static cosmological solutions. At the time the present philosophical view was steady-state model of the space, where the Universe has been aro

    		•