--%>
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 Weber or SI unit of magnetic flux

    Weber: Wb (after W. Weber, 1804-1891): The derived SI unit of magnetic flux equivalent to the flux that, connecting a circuit of one turn, generates in it an electromotive force of 1 V as it is decreased to zero at a uniform rate in a period of 1 s; i

    		•
  • Q : When the intermolecular forces are

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

    		•
  • Q : Define Copernican principle Copernican

    Copernican principle (N. Copernicus): The idea, recommended by Copernicus, that the Sun, not the Earth, is at the center of the earth. We now know that neither idea is accurate (that is, the Sun is not even situated at the center of o

    		•
  • Q : Scanning electron and transmission

    Give one benefit of a scanning electron microscope over the transmission electron microscope? Briefly explain it.

    		•
  • Q : Describe Solar water heating Solar

    Solar water heating: Solar water heaters are simple, reliable, famous and widespread. They are probably the Low Carbon technology closest to being commercially practised. The most efficient designs concentrate solar radiation onto a small diameter tub

    		•
  • Q : Define Luxon Luxon : The particle that

    Luxon: The particle that travels solely at c (that is the speed of light in vacuum). All luxons have a rest mass of exactly zero. Though they are mass less, luxons do take momentum. The photons are the prime illustration of luxons (that is the name it

    		•
  • Q : Define neuro-modulators What do you

    What do you mean by the term neuro-modulators? Briefly define it.

    		•
  • Q : Explain Joules laws and Joule's

    Joule's laws (J.P. Joule) Joule's first law: The heat Q generated whenever a current I flows via a resistance R for a specified time t is specified by: Q = I2

  • Q : What is Hawking temperature Hawking

    Hawking temperature: The temperature of a black hole is caused by the emission of the hawking radiation. For a black hole with mass m, it is illustrated as: T = (hbar c3)/(8 pi G k m).

    		•
  • 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?

    		•