--%>
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 magnetically coupled pair

    When one coil of a magnetically coupled pair has a current of 5.0A, the resulting fluxes Φ11 and Φ21 are 0.2mWb and 0.4mWb, respectively.  If the turns are N1 = 500 and N2 = 1500, find L1, L2, M and the coeffici

    		•
  • 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 : What is Laplace equation Laplace

    Laplace equation (P. Laplace): For the steady-state heat conduction in 1-dimension, the temperature distribution is the explanation to Laplace's equation, which defines that the second derivative of temperature with respect to displac

    		•
  • 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 : Define Mach number Mach number (E.

    Mach number (E. Mach): It is the ratio of the speed of an object in a specified medium to the speed of sound in that medium.

    		•
  • Q : Define Cosmological redshift

    Cosmological redshift: The effect where light emanates from a distant source appears redshifted since of the expansion of the space time itself.

    		•
  • Q : On which gravitational force depends

    Explain in short on which the gravitational force depends on?

    		•
  • Q : Magnetism what's the unit of Curie

    what's the unit of Curie constant and how to calculate Bohr magneton from the plot of 1/Khi vs Temperature(K)?

    		•
  • Q : Define Tau-theta paradox Tau-theta

    Tau-theta paradox (1950s): Whenever two distinct kinds of kaons, tau and theta (nowadays tau refers to a totally different particle) decay, tau decays into three particles, whereas the theta decays into two. The tau and theta vary onl

    		•
  • Q : Problem on multi level TDM Ten sources,

    Ten sources, six with a bit rate of 200 Kbps and four with a bit rate of 400Kbps are to be combined using multi level TDM  with no sync bits. Answer the questions below about the final phase of multiplexing: a

    		•