--%>
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 : Faradays laws of electrolysis or

    Explain Faradays laws of electrolysis or describe Faradays first law and Faradays second law? Faraday's laws of electrolysis (M. Faraday):

  • Q : Why electron and proton encompass

    Explain in short why electron and proton encompass similar charge while the proton is 1836 times heavier?

    		•
  • 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 : Define Lenzs law Lenz's law (H.F. Lenz;

    Lenz's law (H.F. Lenz; 1835): The induced electric current always flows in such a direction that it resists the change generating it.

    		•
  • Q : Explain Photoelectric effect

    Photoelectric effect: An effect described by A. Einstein that demonstrates that light seems to be made up of particles, or photons. The light can excite electrons (termed as photoelectrons in this context) to be ejected from the metal. Light with a fr

    		•
  • Q : Define Tesla or SI unit of the magnetic

    Tesla: T (after N. Tesla, 1870-1943): The derived SI unit of the magnetic flux density stated as the magnetic flux density of a magnetic flux of 1 Wb via an area of 1 m2; it therefore has units of Wb/m2.

    		•
  • Q : Explain Coanda effect Coanda effect:

    Coanda effect: The effect which points out that a fluid tends to flow all along a surface, instead of flowing via free space.

    		•
  • Q : Problem on waveforms The voltage v mV

    The voltage v mV in a circuit is given by: v = 20 sin (200 Πt - 0.7854)           where t is the time in seconds (a) State the amplitude, frequency, period and phase angle of v.(b) Determine the initial voltage.(c) Determin

    		•
  • Q : Scanning electron and transmission

    Give one benefit of a scanning electron microscope over the transmission electron microscope? Briefly explain it.

    		•
  • Q : Define Copernican principle Copernican

    Copernican principle (N. Copernicus): The idea, recommended by Copernicus, that the Sun, not the Earth, is at the center of the earth. We now know that neither idea is accurate (that is, the Sun is not even situated at the center of o

    		•