Editing Fifth force (section)

===Other approaches===
Some experiments used a lake plus a tower that is {{val|320|u=m}}eters high.<ref>{{cite journal |last1=Liu |first1=Yi-Cheng |last2=Yang |first2=Xin-She |last3=Zhu |first3=Heng-Bin |last4=Zhou |first4=Wen-Hu |last5=Wang |first5=Qian-Shen |last6=Zhao |first6=Zhi-Qiang |last7=Jiang |first7=Wei-Wei |last8=Wu |first8=Chuan-Zhen |title=Testing non-Newtonian gravitation on a 320&nbsp;m tower |journal=Physics Letters&nbsp;A |date=September 1992 |volume=169 |issue=3 |pages=131–133 |doi=10.1016/0375-9601(92)90582-7 |bibcode=1992PhLA..169..131L}}</ref> A comprehensive review by [[Ephraim Fischbach]] and Carrick Talmadge suggested there is no compelling evidence for the fifth force,<ref>{{cite journal |last1=Fischbach |first1=Ephraim |last2=Talmadge |first2=Carrick |title=Six years of the fifth force |journal=Nature |date=19 March 1992 |volume=356 |issue=6366 |pages=207–215 |doi=10.1038/356207a0 |bibcode=1992Natur.356..207F|s2cid=21255315 }}</ref> though scientists still search for it. The Fischbach–Talmadge article was written in 1992, and since then, other evidence has come to light that may indicate a fifth force.<ref>{{cite journal |last1=Jenkins |first1=Jere H. |last2=Fischbach |first2=Ephraim |last3=Buncher |first3=John B. |last4=Gruenwald |first4=John T. |last5=Krause |first5=Dennis E. |last6=Mattes |first6=Joshua J. |title=Evidence of correlations between nuclear decay rates and Earth–Sun distance |journal=Astroparticle Physics |date=August 2009 |volume=32 |issue=1 |pages=42–46 |arxiv=0808.3283 |doi=10.1016/j.astropartphys.2009.05.004 |bibcode=2009APh....32...42J|s2cid=119113836 }}</ref>

The above experiments search for a fifth force that is, like gravity, independent of the composition of an object, so all objects experience the force in proportion to their masses. Forces that depend on the composition of an object can be very sensitively tested by [[torsion balance]] experiments of a type invented by [[Loránd Eötvös]]. Such forces may depend, for example, on the ratio of [[proton]]s to [[neutron]]s in an atomic nucleus, nuclear spin,<ref>{{cite book |last1=Hall |first1=A. M. |title=Progress in High Energy Physics |last2=Armbruster |first2=H. |last3=Fischbach |first3=E. |last4=Talmadge |first4=C. |publisher=Elsevier |year=1991 |editor=Hwang |editor-first=W.-Y. Pauchy |location=New York |pages=325–339 |chapter=Is the Eötvös experiment sensitive to spin? |display-editors=etal}}</ref> or the relative amount of different kinds of [[binding energy]] in a nucleus (see the [[semi-empirical mass formula]]). Searches have been done from very short ranges, to municipal scales, to the scale of the [[Earth]], the Sun, and [[dark matter]] at the center of the galaxy.