--%>
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 Volt or SI unit of electric

    Volt: V (after A. Volta, 1745-1827): The derived SI unit of electric potential, stated as the difference of potential among the two points on a conductor fetching  a constant current of 1 A whenever the power dissipated between the points is 1 W;

    		•
  • Q : How radiation emitted from the body

    Describe the procedure how radiation emitted from the body? Illustrate in brief.

    		•
  • Q : Define Landauers principle Landauer's

    Landauer's principle: The principle which defines that it doesn't explicitly take energy to calculate data, however instead it takes energy to remove any data, as erasure is a vital step in computation.

    		•
  • Q : Simulation using VMD and NMD programes

    I need the homework to be finished in five days. and could you please tell me if you are familiar with VMD and NMD simulation programs or not? I will send you some docments that I think it could help to solve the homework questions. But please send me an email so I can attached both files. all b

    		•
  • Q : Conservation laws and illustrations of

    Explain Conservation laws and illustrations of conservation laws (Conservation of mass-energy, electric charge, linear momentum and angular momentum) ? Conservation laws: The law which states that,

    		•
  • Q : Define Zeeman Effect or Zeeman line

    Zeeman Effect: Zeeman line splitting (P. Zeeman; 1896): Zeeman Effect is the splitting of lines in a spectrum whenever the source is exposed to the magnetic field.

    		•
  • Q : Define Watt or SI unit of power Watt: W

    Watt: W (after J. Watt, 1736-1819): The derived SI unit of power, stated as a power of 1 J acting over the period of 1 s; it therefore has the units of J/s.

    		•
  • Q : What is Huygens construction Huygens'

    Huygens' construction: Huygens ‘Principle (C. Huygens): The mechanical propagation of the wave (specially, of light) is equal to supposing that every point on the wave front acts as a point source of the wave emission.

    		•
  • Q : How asteroids are formed Explain how

    Explain how asteroids are formed? Describe.

    		•
  • Q : Problem on two coupled coils connected

    In a series adding connection, two coupled coils have equivalent inductances LA; in a series opposing connection, LB. Determine an expression for M in terms of LA and LB. What does the outcome suggest?

    		•