--%>
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 Einstein-Podolsky-Rosen effect

    Einstein-Podolsky-Rosen effect: EPR effect: Consider the subsequent quantum mechanical thought-experiment: Take a particle that is at rest and has spun zero (0). This spontaneously decays into two fermions (spin 1/2 particles), that stream away in the

    		•
  • Q : What is Complementarity principle

    Complementarity principle (N. Bohr): The principle that a specified system can’t exhibit both wave-like behavior and particle-like behavior at similar time. That is, some experiments will reveal the wave-like nature of a system,

    		•
  • Q : What is Lawson criterion Lawson

    Lawson criterion (J.D. Lawson): This is the condition for the discharge of energy from a thermonuclear reactor. This is usually stated as the minimum value for the product of the density of the fuel particles and the energy imprisonme

    		•
  • Q : Define Pauli Exclusion Principle Pauli

    Pauli Exclusion Principle (W. Pauli; 1925): No two similar fermions in a system, like electrons in an atom, can contain an identical set of the quantum numbers.

    		•
  • Q : Problem on multiplexed channels 4

    4 channels, two with a bit-rate of 200 kbps and two with a bit-rate of 150 Kbps are to be multiplexed employing multiple slots TDM with no sync bits. a. Find out the size of a frame in bits?

    Q : What is Kirchhoffs law of radiation

    Kirchhoff's law of radiation (G.R. Kirchhoff): The emissivity of a body is equivalent to its absorbptance at similar temperature.

    		•
  • Q : Candela Candela : The basic SI unit of

    Candela: The basic SI unit of luminous intensity stated as the luminous intensity in a given direction of a source which emits monochromatic photons of frequency 540 x 1012 Hz and encompasses a radiant intensity in the direction of 1/683 W/

    		•
  • Q : What is Super fluidity Super fluidity :

    Super fluidity: The phenomenon by which, at adequately low temperatures, a fluid can flow with zero (0) viscosity. These causes are related with the superconductivity.

    		•
  • Q : Define Doppler Effect Doppler Effect

    Doppler Effect (C.J. Doppler): The waves emitted by a moving object as received by an observer will be blue shifted (compressed) when approaching, redshifted (that is, elongated) if receding. This takes place both in sound and also el

    		•
  • Q : Development of Missile technology Name

    Name the women scientist who played the essential role in the development of Missile technology of India and is nick named as the ‘Missile Woman’?

    		•