Table 1 Legend of symbols used in the text and their signification.
Parameters | Signification |
|---|---|
R | Outer radius of a spherical shell signal |
Δ, ΔM, | Thickness, maximum thickness, and average thickness of a spherical shell signal |
Ω0 | Solid angle of a conical beam signal |
Ro | Observable radius |
RM | Maximum possible distance of an emitter from the Earth |
tM = (RM + ΔM)/c | Age of the oldest detectable signal |
N | Number of galactic signals emitted within a time tM from present |
| Density probability that an emitter is found at |
T* | Time interval spanned by the age distribution of communication civilizations in the Milky Way. |
ϕ | Detection probability (it is defined as the probability that there is at least one emitter within a distance Ro whose signal intercepts the Earth) |
| Mean number of detectable emitters |
