Drake equation

The result of all the discussions was the Drake equation, which in spite of its mathematical formalism, provides no final answers, but at best estimates of the number... 

Apart from the factor R, all the values need to be estimated. Thus, the values of N vary by several orders of magnitude (from 108 to 10 3) The value of R is assumed to be 20 per year. Since estimates of all the other factors vary so much, some researchers consider that attempts to use the Drake equation to shed more light on the ETI question are useless. 

Taking a value of 107 for N would mean that in our galaxy (with its perhaps 100 billion stars), there could be several million planets with life forms capable of interstellar communication. However, if these were distributed statistically, the nearest would still be 200 light years away from Earth. One point is important the term probability used in the Drake equation is interpreted in the sense of subjective probability (a term from the nomenclature used by statisticians and probability theorists), as the numerical value of this probability is determined only by the experience of the scientist concerned (Casti, 1989). Casti also provides more information on the Drake factors (apart from the factor fs) in the chapter Where are they then In summary, we can say that the Drake equation is a first attempt to quantify the ETI problem in order to move from the area of science fiction and pure speculation to that of serious scientific debate. 

The prospect of intelligent life anywhere in the Universe has been puzzling astronomers and recently astrobiologists, and there have been some attempts to estimate probabilities. This led Drake to construct a now famous equation that collects the ideas together the Drake equation. It is a mathematical representation of factors relating the probability of finding life and, in particular, an intelligent civilisation elsewhere in the Universe. This is an extreme example of hypothesis multiplication and should be treated with caution. The equation is written ... 

The Drake equation is a just a mathematical way of saying who knows but it does allow the factors that might control the origins of life to be identified that said, it is probably the worst calculation in the book. 

Drake equation The factors that might effect the evolution of an intelligent civilisation collected in one equation. 

Use the Drake equation found at http // www.pbs.org/lifebeyondearth/listening/ drake.html to predict the likelihood that intelligent extraterrestrials exist and are trying to contact us from within the Milky Way galaxy. Why is it likely that all of the aliens in the movie are made of the same elements as Earthlings ... 

Heat transfer from immersed bodies is discussed in detail by Eckert and Drake, Jakob, and Knudsen and Katz (see Tutreduction General References ), where equations for local coefficients and the effects of uuheated starting length are presented. Equation (5-44) may also be expressed as... 

Drake, R.L., 1972. A general mathematical survey of the coagulation equation. In Topics in current aerosol research, Pt. 2. Eds. G.M. Tidy and J.R. Brocks, New York Pergamon. 

Calculations Drake eguation Use of this equation, including estimates of the optimistic and pessimistic calculations, for the existence of other life forms... 

In Fig. 6, we report the radius an the mass of the compact star RX J1856.5-3754 inferred by Walter Lattimer (2002) (see also Kaplan et al. 2002) from the fit of the full spectral energy distribution for this isolated radio-quite neutron star , after a revised parallax determination (Kaplan et al. 2002) which implies a distance to the source of 117 12 pc. Comparing the mass-radius box for RX J1856.5-3754 reported in Fig. 6 with the theoretical determination of the MR relation for different equations of state, one concludes that RX J1856.5-3754 could be (see e.g. Fig. 2 in Walter Lattimer, 2002) either an hadronic star or an hybrid or strange star (see also Drake et al. 2002). 

The differential equations (Equation 5.2a or b) can be solved by integration after introducing the actual dependence of k on the time, t (or on the volume of the eluate, V, which has passed through the column) from the start of the gradient until the elution of the band maximum. Freiling [26] and Drake [27] were the first to introduce this approach, which has been used later to derive equations allowing calculations of gradient retention data in various LC modes [2,4-7,28-30]. 

In table 2 our result is compared with the UV spectroscopic result of Klein et al. [26], Also shown are the theoretical results of Zhang et al. [2], Plante et al. [27], and Chen et al. [28], The first of these uses perturbation theory, with matrix elements of effective operators derived from the Bethe-Salpeter equation, evaluated with high precision solutions of the non-relativistic Schrodinger equation. This yields a power series in a and In a. The calculations of Zhang et al. include terms up to O(o5 hi a) but omit terms of 0(ary) a.u. The calculations of Plante et al. use an all orders relativistic perturbation theory method, while those of Chen et al. use relativistic configuration interaction theory. These both obtain all structure terms, up to (Za)4 a.u., and use explicit QED corrections from Drake [29],... 

Reaction of the metal ethoxide [M(OEt)2(HOEt)4] with the desired /3-diketone has been used as an anhydrous method to Group 2 /3-diketonates and mixed ligand/3-diketonate-alkoxide compounds. Presumably, the liberated HOR has a lower binding ability compared to liberated H20. Drake et al. have prepared [Sr3(tmhd)6(Htmhd)] and [Ba4(tmhd)8] by the reaction of Eq. (19).177 Equation (20) gives the generalized reaction for formation of mixed ligand compounds of formula [M(X)n(OR)2 ]) .184185... 

Silver oxide An early (1905) study by Lewis [34] of the kinetics of decomposition of Ag20 was a notable contribution. The dissociation in oxygen (760 Torr, 593 to 623 K) showed a long induction period followed by a sigmoid nr-time curve which fitted the Prout-Tompkins equation with = 133 kJ mol. Benton and Drake [35] studied the kinetics of the reversible dissociation using a sample of finely-divided active metal. The rate of reaction at 433 K fitted the expression ... 

Mercury-penetration Method By equating the force due to surface tension (which tends to keep mercury out of a pore) to the applied force, Ritter and Drake obtained... 

For additional solutions of the discrete and continuous coagulation equations, the interested reader may wish to consult Drake (1972), Mulholland and Baum (1980), Tambour and Seinfeld (1980), and Pilinis and Seinfeld (1987). 

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