--%>
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 : Problem on beam For the beam

    For the beam illustrated below, we require to determine: (A) the support reactions

    		•
  • Q : Explain Malus law Malus' law (E.L.

    Malus' law (E.L. Malus): The light intensity I of a ray with primary intensity I0 travelling via a polarizer at an angle theta among the polarization of the light ray and the polarization axis of the polarizer is specified by:

    Q : What is Boltzmann constant Boltzmann

    Boltzmann constant: k (L. Boltzmann) - The constant that explains the relationship between kinetic energy and temperature for molecules in an ideal gas. This is equivalent to the 1.380 622 x 10-23 J/K.

    		•
  • Q : What is Arago spot What is  Arago

    What is Arago spot? The bright spot which appears in the shadow of a consistent disc being backlit by monochromatic light originating from a point source. &n

    		•
  • Q : What is Magnus effect Magnus effect :

    Magnus effect: The rotating cylinder in a moving fluid drags a few of the fluid about with it, in its direction of rotation. This raises the speed in that area, and therefore the pressure is lower. Therefore, there is a total force on the cylinder in

    		•
  • Q : Define Faint Faint , young sun paradox

    Faint, young sun paradox: The theories of stellar evolution point out that as stars mature on the main series, they grow gradually hotter and brighter; computations propose that at as regards the time of the formation of Earth, the Su

    		•
  • Q : Define Carnots theorem Carnot's theorem

    Carnot's theorem (S. Carnot): The theorem that states that no engine operating between the two temperatures can be more proficient than a reversible engine.

    		•
  • 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 : What is Meissner effect Meissner effect

    Meissner effect (W. Meissner; 1933): The reduction of the magnetic flux in a superconducting metal whenever it is cooled beneath the transition temperature. That is the superconducting materials imitate magnetic fields.

    		•
  • Q : What is Bernoulli's equation

    Bernoulli's equation - In an ir-rotational fluid, the sum of static pressure, the weight of the fluid per unit mass times the height and half of the density times the velocity squared is steady all through the fluid 

    		•