--%>
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 Stefan-Boltzmann law

    Stefan-Boltzmann law (Stefan, L. Boltzmann): The radiated power P (that is the rate of emission of electromagnetic energy) of a hot body is proportional to the radiating surface area, A, and the 4th power of the thermodynamic temperature, T. The const

    		•
  • 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 : Explain avogadro's hypothesis

    Avogadro's hypothesis (Count A. Avogadro; 1811): Equivalent volumes of all gases at similar temperature and pressure contain equivalent numbers of molecules. This is, in fact, true only for the ideal gases.  <

    		•
  • Q : Problem on multi level TDM Ten sources,

    Ten sources, six with a bit rate of 200 Kbps and four with a bit rate of 400Kbps are to be combined using multi level TDM  with no sync bits. Answer the questions below about the final phase of multiplexing: a

    		•
  • Q : Why sun emerge flat throughout sunrise

    Briefly explain the reason why does sun emerge flat throughout sunrise and sunset?

    		•
  • 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

    		•
  • 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 : Define Newton meter What do you mean by

    What do you mean by the term Newton meter? Explain briefly?

    		•
  • Q : Define Tesla or SI unit of the magnetic

    Tesla: T (after N. Tesla, 1870-1943): The derived SI unit of the magnetic flux density stated as the magnetic flux density of a magnetic flux of 1 Wb via an area of 1 m2; it therefore has units of Wb/m2.

    		•
  • Q : Define neuro-modulators What do you

    What do you mean by the term neuro-modulators? Briefly define it.

    		•