--%>
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 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 : Semiconductors and magnetism I need

    I need well-explained answers on the questions in attached documents

    		•
  • Q : Define Siemens or SI unit of an

    Siemens: S (after E.W. von Siemens, 1816-1892): The derived SI unit of an electrical conductance equivalent to the conductance of an element which has a resistance of 1 O [ohm]; this has units of O-1.

    		•
  • Q : Explain the cause of Brownian motion

    Briefly define or explain the cause of Brownian motion?

    		•
  • Q : Explain Chronology protection conjecture

    Chronology protection conjecture (S.W. Hawking): The notion that the formation of any closed time like curve will (automatically) involuntarily be destroyed by the quantum fluctuations as soon as it is made. In another words, the quan

    		•
  • Q : Define Tardon Tardon : A particle that

    Tardon: A particle that has a positive real mass and travels at a speed very less than c in all inertial frames.

    		•
  • Q : Define Einstein-Podolsky-Rosen effect

    Einstein-Podolsky-Rosen effect: EPR effect: Consider the subsequent quantum mechanical thought-experiment: Take a particle that is at rest and has spun zero (0). This spontaneously decays into two fermions (spin 1/2 particles), that stream away in the

    		•
  • Q : Calculate the intensity I along y axis

    As shown in the figure below, a source at S is sending out a spherical wave: E1=(A×D/r) cos(wt-2πr/λ); where r is the distance to source

    		•
  • Q : What is No-hair conjecture No-hair

    No-hair conjecture (1960s): The conjecture (confirmed in the 1970s and 1980s) in general relativity that a black hole has merely three salient external characteristics: angular momentum, mass, and electric charge. All the other proper

    		•
  • 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?

    		•