--%>
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 : What is Complementarity principle

    Complementarity principle (N. Bohr): The principle that a specified system can’t exhibit both wave-like behavior and particle-like behavior at similar time. That is, some experiments will reveal the wave-like nature of a system,

    		•
  • Q : Define Steradian or SI unit of solid

    Steradian: sr: The supplementary SI unit of solid angle stated as the solid central angle of a sphere which encloses a surface on the sphere equivalent to the square of the sphere's radius.

    		•
  • Q : What is Lyman series Lyman series: The

    Lyman series: The sequence that explains the emission spectrum of hydrogen whenever electrons are jumping to the ground state. Each and every line is in the ultraviolet.

    		•
  • Q : Plasma globe AD advantages and

    advantages and disadvantages of a plasma globe

    		•
  • Q : What is Permeability of free space or

    Permeability of free space: magnetic constant: mu_0: The ratio of the magnetic flux density in the substance to the external field strength for vacuum. It is equivalent to 4 pi x 10-7 H/m.

    		•
  • 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 : Heating a bucket of water than the cup

    Briefly describe the reason why it takes longer to heat a bucket of water than the cup of water?

    		•
  • Q : Explain Michelson-Morley experiment

    Michelson-Morley experiment (A.A. Michelson, E.W. Morley; 1887): Probably the most famous null-experiment of all time, designed to confirm the existence of the proposed "lumeniferous aether" via which light waves were considered to pr

    		•
  • Q : Explain Bohr magneton and Bohr radius

    Bohr magneton (N. Bohr) - This is the quantum of magnetic moment. Bohr radius (N. Bohr) - The distance equivalent to the mean distance of an electron from the nucleus in the ground state of hydroge

    		•
  • Q : Define Joule or SI unit of energy Joule

    Joule: J (after J.P. Joule, 1818-1889): The derived SI unit of energy stated as the quantity of work done by moving an object via a distance of 1 m by exerting a force of 1 N; it therefore has units of N m.

    		•