  The gravitational interactions of elementary particles are suppressed by the
Planck scale M_P ~ 10^18 GeV and are typically expected to be far too weak to
be probed by experiments. We show that, contrary to conventional wisdom, such
interactions may be studied by particle physics experiments in the next few
years. As an example, we consider conventional supergravity with a stable
gravitino as the lightest supersymmetric particle. The next-lightest
supersymmetric particle (NLSP) decays to the gravitino through gravitational
interactions after about a year. This lifetime can be measured by stopping
NLSPs at colliders and observing their decays. Such studies will yield a
measurement of Newton's gravitational constant on unprecedentedly small scales,
shed light on dark matter, and provide a window on the early universe.
