--%>
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 Mediocrity principle Mediocrity

    Mediocrity principle: The principle that there is nothing predominantly interesting about our position in space or time, or regarding ourselves. This principle most likely first made its real manifestation in the scientific community whenever Shapley

    		•
  • 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 : Explain Newtons law of universal

    Newton's law of universal gravitation (Sir I. Newton): Two bodies exert a pull on each other with equivalent and opposite forces; the magnitude of this force is proportional to the product result of the two masses and is too proportional to the invers

    		•
  • 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 : 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 : When the intermolecular forces are

    Describe when the intermolecular forces are strongest? Briefly state it.

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

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

    		•
  • Q : Define Spin-orbit effect Spin-orbit

    Spin-orbit effect: The effect that causes atomic energy levels to be split since electrons contain intrinsic angular momentum (that is spin) in summation to their extrinsic orbital angular momentum.

    		•
  • Q : What is Refraction law Refraction law:

    Refraction law: For a wave-front travelling via a boundary among two media, the first with a refractive index of n1, and the other with one of n2, the angle of incidence theta is associated to the angle of refraction phi by:

    		•
  • Q : Why the length of a standard meter

    Describe the reason in short why the length of a standard meter re-defined in the year of 1983?

    		•