--%>
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 : Define anti-aliasing What do you

    What do you understand by the term anti-aliasing? Describe briefly?

    		•
  • Q : Define Static limit Static limit : The

    Static limit: The distance from a rotating black hole where no spectator can possibly stay at rest (with respect to the far-away stars) since of inertial frame dragging; this area is external of the event horizon, apart from at the poles where it meet

    		•
  • 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 

    		•
  • Q : Define Planck constant Planck constant

    Planck constant: h: The basic constant equivalent to the ratio of the energy of a quantum of energy to its frequency. This is the quantum of action. This has the value 6.626 196 x 10-34 J s.

    		•
  • Q : Simulation using VMD and NMD programes

    I need the homework to be finished in five days. and could you please tell me if you are familiar with VMD and NMD simulation programs or not? I will send you some docments that I think it could help to solve the homework questions. But please send me an email so I can attached both files. all b

    		•
  • Q : What is Magnetic monopole Magnetic

    Magnetic monopole: The hypothetical particle that comprises sources and sinks of the magnetic field. The magnetic monopoles have never been found, however would only cause pretty minor modifications to the Maxwell's equations. They also appear to be p

    		•
  • Q : Define Laue pattern Laue pattern (M.

    Laue pattern (M. von Laue): The pattern generated on a photographic film whenever high-frequency electromagnetic waves (like x-rays) are fired at the crystalline solid.

    		•
  • Q : Define Grandfather paradox Grandfather

    Grandfather paradox: The paradox proposed to discount time travel and exhibit why it violates causality. State that your grand-father makes a time machine. In the current time, you employ his time machine to go back in time a few decades to a point be

    		•
  • Q : How radiation emitted from the body

    Describe the procedure how radiation emitted from the body? Illustrate in brief.

    		•
  • Q : What is Edwards-Casimir quantum vacuum

    What is Edwards-Casimir quantum vacuum drive: The hypothetical drive developing the peculiarities of quantum mechanics by restricting permitting wavelengths of the virtual photons on one side of the drive (that is the bow of the ship); the pressure pr

    		•