--%>
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 Lenzs law Lenz's law (H.F. Lenz;

    Lenz's law (H.F. Lenz; 1835): The induced electric current always flows in such a direction that it resists the change generating it.

    		•
  • Q : What are Woodward-Hoffmann rules

    Woodward-Hoffmann rules: The rules leading the formation of products throughout certain kinds of organic reactions.

    		•
  • Q : Problem on Adiabatic law When air is

    When air is compressed adiabatically the law connecting the absolute temperature T and the pressure P is of the form T = A.Pn where A and N are constants. Show by drawing a suitable linear graph that the experimental dat

    		•
  • 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 : What is Arago spot What is  Arago

    What is Arago spot? The bright spot which appears in the shadow of a consistent disc being backlit by monochromatic light originating from a point source. &n

    		•
  • Q : What is Meissner effect Meissner effect

    Meissner effect (W. Meissner; 1933): The reduction of the magnetic flux in a superconducting metal whenever it is cooled beneath the transition temperature. That is the superconducting materials imitate magnetic fields.

    		•
  • 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 : What do you mean by the term alloy What

    What do you mean by the term alloy? Briefly illustrate it.

    		•
  • Q : Explain Muon experiment Muon

    Muon experiment: The experiment that demonstrates proves the prediction of time dilation by the special relativity. Muons, that are short-lived subatomic particles, are made with enormous energy in the upper environment by the interaction of energetic

    		•
  • Q : Universal law of universal gravitation

    Describe the universal law of universal gravitation? Briefly describe it.

    		•