Editing Drake equation (section)

==Usefulness==
[[File:C G-K - DSC 0421.jpg|thumb|upright=0.9|The [[Allen Telescope Array]] for SETI]]
The Drake equation results in a summary of the factors affecting the likelihood that we might detect radio-communication from intelligent extraterrestrial life.<ref name="Burchell">{{cite journal |author=Burchell |first=M. J. |date=2006 |title=W(h)ither the Drake equation? |journal=International Journal of Astrobiology |volume=5 |issue=3 |pages=243–250 |bibcode=2006IJAsB...5..243B |doi=10.1017/S1473550406003107 |s2cid=121060763}}</ref><ref name="NOVA"/><ref>
{{cite web
 |last=Jones |first=D. S.
 |date=26 September 2001
 |title=Beyond the Drake Equation
 |url=http://frombob.to/drake.html
 |access-date=2013-04-17
}}</ref> The last three parameters, {{math|''f''<sub>i</sub>}}, {{math|''f''<sub>c</sub>}}, and {{mvar|L}}, are not known and are very difficult to estimate, with values ranging over many orders of magnitude (see {{Section link|2=Criticism|nopage=y}}). Therefore, the usefulness of the Drake equation is not in the solving, but rather in the contemplation of all the various concepts which scientists must incorporate when considering the question of life elsewhere,<ref name="Burchell"/><ref name="December 2002"/> and gives the question of life elsewhere a basis for [[Scientific method|scientific analysis]]. The equation has helped draw attention to some particular scientific problems related to life in the universe, for example [[abiogenesis]], the development of [[multi-cellular life]], and the development of [[intelligence]] itself.<ref>{{cite web
 |year=2010
 |title=The Search For Life : The Drake Equation 2010 – Part 1
 |url=https://www.youtube.com/watch?list=PL56DCB81E2F59166A&v=U3UyAoYkhTo&feature=player_embedded
 |publisher=[[BBC Four]]
 |access-date=2013-04-17
}}</ref>

Within the limits of existing human technology, any practical search for distant intelligent life must necessarily be a search for some manifestation of a distant technology. After about 50 years, the Drake equation is still of seminal importance because it is a 'road map' of what we need to learn in order to solve this fundamental existential question.<ref name="Burchell"/> It also formed the backbone of [[astrobiology]] as a science; although speculation is entertained to give context, astrobiology concerns itself primarily with [[hypotheses]] that fit firmly into existing [[Theory#Science|scientific theories]]. Some 50 years of SETI have failed to find anything, even though radio telescopes, receiver techniques, and computational abilities have improved significantly since the early 1960s. SETI efforts since 1961 have conclusively ruled out widespread alien emissions near the 21&nbsp;cm wavelength of the [[Hydrogen frequencies|hydrogen frequency]].<ref>[http://www.astronomynow.com/news/n1004/SETI/ SETI: A celebration of the first 50 years]. Keith Cooper. ''Astronomy Now''. 2000</ref>