--%>
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 : Explain Curie-Weiss law Curie-Weiss law

    Curie-Weiss law (P. Curie, P.-E. Weiss): A more broad form of Curie's law that states that the susceptibility, khi, of a paramagnetic substance is associated to its thermodynamic temperature T by the equation:

    Q : Candela Candela : The basic SI unit of

    Candela: The basic SI unit of luminous intensity stated as the luminous intensity in a given direction of a source which emits monochromatic photons of frequency 540 x 1012 Hz and encompasses a radiant intensity in the direction of 1/683 W/

    		•
  • Q : What is balmer series Balmer series (J.

    Balmer series (J. Balmer; 1885): An equation that explains the emission spectrum of hydrogen whenever an electron is jumping to the next orbital; four of the lines are in visible spectrum, and the remainder (residue) are in the ultraviolet.

    		•
  • Q : Scanning electron and transmission

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

    		•
  • Q : Atomic model which the Erwin

    Briefly state the atomic model which the Erwin Schrodinger creates?

    		•
  • Q : Biot-Savart law Biot-Savart law (J.B.

    Biot-Savart law (J.B. Biot, F. Savart) - The law which explains the contributions to the magnetic field by an electric current. This is analogous to the Coulomb's law. Mathematically: dB = (mu0 I)/(4 pi r2) dl cross e

    		•
  • Q : Explain Tachyon paradox Tachyon

    Tachyon paradox: The argument explaining that tachyons (should they subsist, of course) can’t carry an electric charge. For an imaginary-massed particle travelling faster than c, less energy the tachyon has, the faster it travels, till at zero e

    		•
  • Q : Newtons laws of motion or Newtons

    Explain Newtons laws of motion or Newtons first law, second law and third law of motion? Newton's laws of motion (Sir I. Newton)

    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 : What is De Broglie wavelength De

    De Broglie wavelength (L. de Broglie; 1924): The prediction that particles too contain wave characteristics, where the efficient wavelength of the particle would be inversely proportional to its momentum, where the constant of the pro

    		•