--%>
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 : What is Lawson criterion Lawson

    Lawson criterion (J.D. Lawson): This is the condition for the discharge of energy from a thermonuclear reactor. This is usually stated as the minimum value for the product of the density of the fuel particles and the energy imprisonme

    		•
  • Q : Define Equivalence principle

    Equivalence principle: The fundamental postulate of Sir Einstein’s general theory of relativity that posits that acceleration is basically indistinguishable from the gravitational field. In another words, when you are in an elevator that is utte

    		•
  • Q : Energy and light My question is Eph =

    My question is Eph = hcT. I have to rearrange the equation to make b b the subject and also find the SI units for b and how and why they are those units.....

    		•
  • Q : Difference between the cathode ray and

    Illustrate the difference between the cathode ray and beta ray?

    		•
  • Q : Explain Rayleigh-Jeans law

    Rayleigh-Jeans law: For a blackbody at the thermodynamic temperature T, the radiance R over a range of frequencies between the nu and nu + dnu is specified by: R = 2 pi nu2 k T/c2.<

    		•
  • 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 : Explain Kirchhoffs laws or Kirchhoffs

    Kirchhoff's laws (G.R. Kirchhoff) Kirchhoff's first laws: An incandescent solid or gas in high pressure will generate a continuous spectrum.

    Q : Explain quantum physics why quantum

    why quantum physics is studied? give me some of topics

    		•
  • Q : Non-Parametric Tests Activity

    Activity 9:   Non-Parametric Tests    4Non-Parametric Tests While you have learned a number of parametric statistical techniques, you are also aware that if the assumptions related to

    		•
  • 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?

    		•