--%>
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 Faradays law Faraday's law (M.

    Faraday's law (M. Faraday): The line integral of the electric field about a closed curve is proportional to the instant time rate of change of the magnetic flux via a surface bounded by that closed curve; in the differential form,

    		•
  • Q : Law of Lamberts Cosine State the law of

    State the law of Lamberts Cosine? Describe briefly?

    		•
  • Q : Ampere's law Explain  Ampere's law?  

    Explain Ampere's law?   Ampere's law (A.M. Ampere):

  • Q : Problem on two coupled coils connected

    In a series adding connection, two coupled coils have equivalent inductances LA; in a series opposing connection, LB. Determine an expression for M in terms of LA and LB. What does the outcome suggest?

    		•
  • Q : What is Universal age paradox Universal

    Universal age paradox: The two most straightforward techniques of computing the age of the Universe -- via red-shift measurements, and via stellar evolution -- outcome incompatible outcomes. Recent (in mid 1990s) measurements of the distances of far-a

    		•
  • Q : Steps to the scientific notation

    Illustrate the steps to the scientific notation? Briefly illustrate the steps.

    		•
  • Q : Explain Lagrange points Lagrange points

    Lagrange points: The points in the vicinity of two massive bodies (like the Earth and Moon) with each others' relevant gravities balance. There are five, labeled L1 via L5. L1, L2, and L3 lie all along the centerline among the centers

    		•
  • 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 : Describe Wiedemann-Franz law

    Wiedemann-Franz law: It is the ratio of the thermal conductivity of any pure metal (substance) to its electrical conductivity is just about constant for any specified temperature. This law holds pretty well apart from at low temperatures.

    		•
  • 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

    		•