--%>
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 Ergosphere Ergosphere: The area

    Ergosphere: The area around a rotating black hole, among the event horizon and the static limit, where the rotational energy can be removed from the black hole.

    		•
  • Q : Define Ohm or SI unit of electric

    Ohm: Omega: O (after G. Ohm, 1787-1854) The derived SI unit of electric resistance, stated as the resistance among two points on a conductor whenever a constant potential difference of 1 V generates a current of 1 A in the conductor;

    		•
  • Q : Why tea kettle sing What is the reason

    What is the reason that the tea kettle sing? Briefly state the reason.

    		•
  • 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 : What is Kerr effect Kerr effect (J.

    Kerr effect (J. Kerr; 1875): The capability of certain substances to refract light waves in a different way whose vibrations are in dissimilar directions whenever the substance is located in an electric field.

    		•
  • Q : What is baryon decay Baryon decay - The

    Baryon decay -The idea expected by several grand-unified theories, those classes of subatomic particles termed as baryons (of which the nucleons -- neutrons and protons -- are members) are not eventually stable however indeed de

    		•
  • Q : What is Refraction law Refraction law:

    Refraction law: For a wave-front travelling via a boundary among two media, the first with a refractive index of n1, and the other with one of n2, the angle of incidence theta is associated to the angle of refraction phi by:

    		•
  • Q : Explain Einstein field equation

    Einstein field equation: The cornerstone of Einstein's general theory of relativity, associating the gravitational tensor G to the stress-energy tensor T by the simple equation: G = 8 pi T<

    		•
  • Q : Define Static limit Static limit : The

    Static limit: The distance from a rotating black hole where no spectator can possibly stay at rest (with respect to the far-away stars) since of inertial frame dragging; this area is external of the event horizon, apart from at the poles where it meet

    		•
  • Q : Define Josephson effects Josephson

    Josephson effects (B.D. Josephson; 1962): Electrical effects examined whenever two superconducting materials are separated by a thin layer of the insulating substance.

    		•