--%>
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 Charles law Charles' law (J.A.C.

    Charles' law (J.A.C. Charles; c. 1787): The volume of an ideal gas at constant (steady) pressure is proportional to the thermodynamic temperature of that gas.

    		•
  • 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 : Explain Muon experiment Muon

    Muon experiment: The experiment that demonstrates proves the prediction of time dilation by the special relativity. Muons, that are short-lived subatomic particles, are made with enormous energy in the upper environment by the interaction of energetic

    		•
  • 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 : Explain Right-hand rule Right-hand

    Right-hand rule: The trick for right-handed coordinate systems to establish which way the cross product of two three-vectors will be directed. There are some forms of this rule, and it can be exerted in many manners. If u and v are two vectors that ar

    		•
  • Q : When the intermolecular forces are

    Describe when the intermolecular forces are strongest? Briefly state it.

    		•
  • Q : Continuity of equation or Equation of

    Define Equation of continuity or Continuity of equation: An equation that states that a fluid flowing via a pipe flows at a rate that is inversely proportional to the cross-sectional region of the pipe. That is, when the pipe constric

    		•
  • Q : Define Tardon Tardon : A particle that

    Tardon: A particle that has a positive real mass and travels at a speed very less than c in all inertial frames.

    		•
  • Q : Define Atwood's machine Atwood's

    Atwood's machine: The weight-and-pulley system devised to compute the acceleration due to gravity at Earth's surface by computing the total acceleration of a set of weights of identified mass about a frictionless pulley.

    		•
  • Q : What is Beauty criterion Beauty

    Beauty criterion (Dirac) - The idea that more aesthetically pleasing a theory is the superior it is. In nature this criterion does not stand up to the actual test -- whether or not forecasts of a given theory agree with observational tests -- however

    		•