--%>
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 : What is Lyman series Lyman series: The

    Lyman series: The sequence that explains the emission spectrum of hydrogen whenever electrons are jumping to the ground state. Each and every line is in the ultraviolet.

    		•
  • Q : Measure of the force of gravity Briefly

    Briefly explain the measure of the force of gravity on the object?

    		•
  • Q : Define Trojan points Trojan points : L4

    Trojan points: L4 and L5 are the two dynamically stable Lagrange points (that is, beneath certain conditions).

    		•
  • 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 Heat pumps Heat pumps move heat

    Heat pumps move heat from one place to another. They work similar to refrigeration. The movement of heat takes energy, either electrical energy as in the use of  vapor compression heat pumps or thermal energy as in the use of absorption heat pump

    		•
  • Q : Conservation laws and illustrations of

    Explain Conservation laws and illustrations of conservation laws (Conservation of mass-energy, electric charge, linear momentum and angular momentum) ? Conservation laws: The law which states that,

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

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

  • 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 : What is Beauty criterion Beauty

    Beauty criterion (Dirac) - The idea that more aesthetically pleasing a theory is the superior it is. In nature this criterion does not stand up to the actual test -- whether or not forecasts of a given theory agree with observational tests -- however

    		•
  • Q : Why electron and proton encompass

    Explain in short why electron and proton encompass similar charge while the proton is 1836 times heavier?

    		•