--%>
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 : Calculate the concentration A

    A dual-wavelength spectrometer uses 780 nm and 830 nm. The molar extinction coefficients for oxy-hemoglobin (HbO2) and deoxy-hemoglobin (Hb) at these two wavelengths are: e_HbO2_780nm = 710 cm-1M-1, e_Hb_780nm = 1075 cm

    		•
  • Q : What is Complementarity principle

    Complementarity principle (N. Bohr): The principle that a specified system can’t exhibit both wave-like behavior and particle-like behavior at similar time. That is, some experiments will reveal the wave-like nature of a system,

    		•
  • Q : Explain Stefan-Boltzmann law

    Stefan-Boltzmann law (Stefan, L. Boltzmann): The radiated power P (that is the rate of emission of electromagnetic energy) of a hot body is proportional to the radiating surface area, A, and the 4th power of the thermodynamic temperature, T. The const

    		•
  • Q : Current through resistors How do I find

    How do I find out a maximum current flowing through a resistor with just the resistance of the resistor and it's power rating?

    		•
  • Q : Define Photovoltaics Photovoltaics (PV)

    Photovoltaics (PV): It transform light directly into electricity. The typical current residential installation of 12m2 could produce around 1,300 kWh pa with a peak of around 1.9kW, though larger and more efficient installations are possibl

    		•
  • Q : Weights in pounds of the liquid gallons

    Write down the weights in pounds of the liquid gallons? Briefly describe it.

    		•
  • Q : Procedure to define the Specific Gravity

    Briefly explain the procedure to define the Specific Gravity?

    		•
  • Q : Explain Daltons law of partial pressures

    Dalton's law of partial pressures (J. Dalton): The net pressure of a mixture of ideal gases is equivalent to the sum of the partial pressures of its components; which is the sum of the pressures which each component would exert when it were present al

    		•
  • Q : Problem on spacecraft Assuming that

    Assuming that ground stations are equally distributed on the Earth, how many ground stations are required to maintain constant contact with a spacecraft at 750 km altitude, and 72 degrees inclination?

    		•
  • Q : Information in physics What do you mean

    What do you mean by the term information in physics?

    		•