--%>
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 Daltons law of partial pressures

    Dalton's law of partial pressures (J. Dalton): The net pressure of a mixture of ideal gases is equivalent to the sum of the partial pressures of its components; which is the sum of the pressures which each component would exert when it were present al

    		•
  • Q : Define Permittivity of free space or

    Permittivity of free space: electric constant; epsilon_0: The ratio of the electric displacement to the intensity of the electric field generating it in vacuum. It is equivalent to 8.854 x 10-12 F/m.

    		•
  • Q : Define Pascal or SI unit of pressure

    Pascal: Pa The derived SI unit of pressure stated as 1 N acting over a region of 1 m2; it therefore has units of N/m2

    		•
  • Q : Characteristics of electronics what is

    what is the characteristics of electronics ?

    		•
  • Q : Scanning electron and transmission

    Give one benefit of a scanning electron microscope over the transmission electron microscope? Briefly explain it.

    		•
  • Q : Instrument used to measure the volume

    Name the instrument which is used to measure the volume? Explain in short?

    		•
  • Q : Acceleration during this interval The

    The velocity of a body was observed to be constant throughout five minutes of its motion. Determine its acceleration during this interval?

    		•
  • 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 : What is Gray Gray : Gy (after L.H.

    Gray: Gy (after L.H. Gray, 1905-1965): The derived SI unit of engrossed dose, stated as the absorbed dose in which the energy per unit mass communicated to the matter by the ionizing radiation is 1 J/kg; it therefore has units of J/kg

    		•
  • Q : Report on Radiobiology for Travel Space

    I have a problem in wirting a report on Radiobiology for Travel Space.  Can someone provide me a complete report on the above topic.

    		•