--%>
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 : Characteristics of electronics what is

    what is the characteristics of electronics ?

    		•
  • Q : Define Centrifugal pseudo force

    Centrifugal pseudo force: A pseudo force which takes place whenever one is moving in uniform circular motion. One feels a "force" directed outward from the center of the motion.

    		•
  • Q : Define Static limit Static limit : The

    Static limit: The distance from a rotating black hole where no spectator can possibly stay at rest (with respect to the far-away stars) since of inertial frame dragging; this area is external of the event horizon, apart from at the poles where it meet

    		•
  • 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 : Explain Null experiment Null

    Null experiment: The experiment which, after being performed, yields no outcome. The null experiments are just as significant as non-null experiments; when current theory predicts an observable result (or predicts there must be no observable result),

    		•
  • Q : Define Mole or SI unit of substance

    Mole: mol: The basic SI unit of substance, stated as the quantity of substance which contains as many elementary units (that is, atoms, molecules, ions, and so forth) as there are atoms in 0.012 kg of carbon-12.

    		•
  • Q : What do you mean by the term cardiac

    What do you mean by the term cardiac output? Briefly explain it.

    		•
  • 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 Copernican principle Copernican

    Copernican principle (N. Copernicus): The idea, recommended by Copernicus, that the Sun, not the Earth, is at the center of the earth. We now know that neither idea is accurate (that is, the Sun is not even situated at the center of o

    		•
  • Q : Explain Stern-Gerlach experiment

    Stern-Gerlach experiment (O. Stern, W. Gerlach; 1922): The experiment which explains the features of spin (that is intrinsic angular momentum) as a different entity apart from the orbital angular momentum.

    		•