**Peruse the chapters of any introductory textbook on astronomy and you’ll find the second-most celebrated equation in science: The Drake Equation. Eclipsed in fame only by Einstein’s E = mc ^{2}, this formula was concocted by astronomer Frank Drake in 1961 as an agenda for the first formal meeting on the prospects of future SETI experiments.**

**The straightforward intent of the equation is to provide an estimate of the number of communicating societies in the Galaxy, N. Clearly, if this number is close to zero, there’s little point in devoting telescope time to search for signals from extraterrestrials. If it’s large, then there’s ****reason**** to hope for a discovery that would prove we’re not alone.**

**However, while many of the equations of science are immutable, the Drake Equation is a mixture of parameters whose values, or even ****relevance,**** may change. Some are potentially measurable, such as the number of bio-friendly planets in the Milky Way, and others aren’t – such as ****fc****, the fraction of intelligent species that develop signaling capability – at least until we have actually found a number of technologically adept civilizations.**

**Given this problematic nature, it’s not surprising that many people have offered what they consider “improvements” to Drake’s formulation. Drake himself says he regularly receives correspondence from those who think his equation should be tweaked.**

**Have any of these ideas proven to be worthy? Should the textbooks be altered?**

**click here.**