--%>
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 do you mean by the term geocentric

    What do you mean by the term geocentric? Briefly describe it.

    		•
  • 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 : Define Pascal or SI unit of pressure

    Pascal: Pa The derived SI unit of pressure stated as 1 N acting over a region of 1 m2; it therefore has units of N/m2

    		•
  • Q : Define Olbers paradox Olbers' paradox

    Olbers' paradox (H. Olbers; 1826): If the Universe is infinite, consistent, and unchanging then the whole sky at night would be bright -- concerning as bright as the Sun. The further you stared out into space, the more stars there would be, and theref

    		•
  • Q : Radar gun problem Whenever a radar gun

    Whenever a radar gun states the pitch is 90 miles per hour at what point in the balls travel to home plate is the radar gun evaluating the velocity?

    		•
  • Q : Define Occams razor or Ockhams razor

    Occam's [or Ockham's] razor (William of Occam [or Ockham]; c. 1340): It is the suggestion that the simpler a theory is the better. When two theories forecast the phenomena to the similar accuracy, then the one that is simpler is the better one. Furthe

    		•
  • Q : How elevation and air pressure affects

    Briefly state how does the elevation and air pressure affects the boiling point of water?

    		•
  • Q : Bragg's law Bragg's law - Whenever a

    Bragg's law - Whenever a beam of x-rays strikes a crystal surface in which the layers of ions or atoms are often separated, the maximum intensity of the reflected ray takes place when the complement of the angle of incidence, theta (θ), the wave

    		•
  • Q : Newtons laws of motion Briefly

    Briefly illustrate all the Newton s laws of motion?

    		•
  • Q : Define Newton meter What do you mean by

    What do you mean by the term Newton meter? Explain briefly?

    		•