--%>
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 : Calculate time needed for thermocouple

    A thermocouple of K type is suddenly exposed to air with temperature of 1273K, Initial temperature was 293 K. Calculate the time needed for the thermocouple read the temperature with accuracy of better that 99%. Ignore radiation and conduction. The measuring element has a ball shape of diameter o

    		•
  • Q : Explain Youngs experiment or

    Young's experiment: double-slit experiment (T. Young; 1801): A well-known experiment that exhibits the wave nature of light (and certainly of other particles). The light is passed from a small source into an opaque screen with the two thin slits. The

    		•
  • Q : Explain Fizeau method Fizeau method (A.

    Fizeau method (A. Fizeau, 1851): One of the primary truthfully relativistic experiments intended to compute the speed of light. Light is passed via a spinning cog-wheel driven by running water, is reflected off a far-away mirror, and

    		•
  • Q : Define Determinism principle

    Determinism principle: The principle that when one knows the state to an unlimited accuracy of a system at one point in time, one would be capable to predict the state of that system with unlimited accuracy at any other time, past or the future. For i

    		•
  • Q : Atomic model which the Erwin

    Briefly state the atomic model which the Erwin Schrodinger creates?

    		•
  • Q : Define Second or SI unit of time

    Second: s: The basic SI unit of time, stated as the period of time equivalent to the duration of 9 192 631 770 periods of the radiation analogous to the transition between the two hyperfine levels of the ground state of cesium-133 atom.

    		•
  • 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 : State Hooke's law as it applies to a

    a 6.00 kg mass is situated at (-1.00, 3.00) meters, what is its mass moment of inertia: a)about the x-axis b)about the y-axis c)About a line defined by x=6.00 m The same object is hun

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

    What do you mean by the term positron? Explain in short.

    		•
  • Q : Define Newton meter What do you mean by

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

    		•