--%>
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 : Problem on Orbit cycle Calculate the

    Calculate the hot and cold temperature after 25 orbits. Assume a 100kg spherical spacecraft made of aluminum. Assume that the spacecraft is in an equatorial orbit. How is calculation 1 different for a spacecraft in a 90 degree (polar) orbit?

    		•
  • Q : Define Doppler Effect Doppler Effect

    Doppler Effect (C.J. Doppler): The waves emitted by a moving object as received by an observer will be blue shifted (compressed) when approaching, redshifted (that is, elongated) if receding. This takes place both in sound and also el

    		•
  • Q : Kinematics why rockets are also called

    why rockets are also called as projectile

    		•
  • Q : What is balmer series Balmer series (J.

    Balmer series (J. Balmer; 1885): An equation that explains the emission spectrum of hydrogen whenever an electron is jumping to the next orbital; four of the lines are in visible spectrum, and the remainder (residue) are in the ultraviolet.

    		•
  • Q : Explain Malus law Malus' law (E.L.

    Malus' law (E.L. Malus): The light intensity I of a ray with primary intensity I0 travelling via a polarizer at an angle theta among the polarization of the light ray and the polarization axis of the polarizer is specified by:

    Q : Define Fermats principle Fermat's

    Fermat's principle: principle of least time (P. de Fermat): The principle, put onward by P. de Fermat that explains the path taken by a ray of light among any two points in a system is for all time the path which takes the least time.

    		•
  • Q : Explain Casimir effect Casimir effect

    Casimir effect (Casimir): The quantum mechanical effect, where two very big plates positioned close to each other will experience an attractive force, in the nonattendance of other forces. The cause is implicit particle-antiparticle p

    		•
  • 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 : Define Determinism principle

    Determinism principle: The principle that when one knows the state to an unlimited accuracy of a system at one point in time, one would be capable to predict the state of that system with unlimited accuracy at any other time, past or the future. For i

    		•
  • Q : What do you mean by the term density

    What do you mean by the term density? Briefly explain it.

    		•