--%>
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 : 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 : Calculate time needed for thermocouple

    A thermocouple of K type is suddenly exposed to air with temperature of 1273K, Initial temperature was 293 K. Calculate the time needed for the thermocouple read the temperature with accuracy of better that 99%. Ignore radiation and conduction. The measuring element has a ball shape of diameter o

    		•
  • Q : How energy transformed in windmills

    Explain how is energy transformed in the windmills?

    		•
  • Q : What is Lawson criterion Lawson

    Lawson criterion (J.D. Lawson): This is the condition for the discharge of energy from a thermonuclear reactor. This is usually stated as the minimum value for the product of the density of the fuel particles and the energy imprisonme

    		•
  • Q : What is Roche limit Roche limit : The

    Roche limit: The position about a massive body where the tidal forces due to the gravity of the primary equivalent or exceed the surface gravity of a specified satellite. Within the Roche limit, such a satellite will be interrupted by tides.

    		•
  • Q : Fundamental principles of the regulation

    Describe the fundamental principles of the regulation? Briefly describe the principles?

    		•
  • Q : Weak equivalence or principle of

    Weak equivalence principle: principle of uniqueness of freefall: The idea in general relativity is that the world-line of a freefalling body is sovereign of its composition, structure, or state. This principle, hold by Newtonian mechanics and gravitat

    		•
  • Q : What is Causality principle Causality

    Causality principle: The principle which cause must always precede effect. More properly, when an event A ("the cause") somehow persuades an event B ("the effect") that take

    		•
  • 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

    		•
  • Q : Blackbody radiation What is Blackbody

    What is Blackbody radiation - The radiation - that is the radiance at specific frequencies all across the spectrum -- generated by a blackbody -- which is, a perfect radiator and absorber of the heat. Physicists had complexity exp

    		•