# Einstein's equivalence principle and the gravitational
red shift

**Source**: https://www.maths.tcd.ie/report_series/abstracts/tcdm1111.html
**Parent**: https://www.maths.tcd.ie/research/papers/

**Einstein's equivalence principle and the gravitational
red shift**

Long before the general theory of relativity was finally
formulated in 1916, arguments based entirely on Einstein's
equivalence principle predicted the well known phenomenon
of the gravitational red shift. Precisely the same argu-
ments are widely being used today to derive the same
phenomenon. Accordingly, it is often claimed that the
observed gravitational red shift is a verification of the
equivalence principle rather than a verification of the
full theory of general relativity. Here we show that,
contrary to these claims, the arguments based on the
equivalence principle are false and that only the full
theory of general relativity can correctly and
unambiguously predict the gravitational red shift.