Advancing the Landscape of Multimessenger Science in the Next Decade
  The last decade has brought about a profound transformation in multimessenger
science. Ten years ago, facilities had been built or were under construction
that would eventually discover the nature of objects in our universe could be
detected through multiple messengers. Nonetheless, multimessenger science was
hardly more than a dream. The rewards for our foresight were finally realized
through IceCube's discovery of the diffuse astrophysical neutrino flux, the
first observation of gravitational waves by LIGO, and the first joint
detections in gravitational waves and photons and in neutrinos and photons.
Today we live in the dawn of the multimessenger era. The successes of the
multimessenger campaigns of the last decade have pushed multimessenger science
to the forefront of priority science areas in both the particle physics and the
astrophysics communities. Multimessenger science provides new methods of
testing fundamental theories about the nature of matter and energy,
particularly in conditions that are not reproducible on Earth. This white paper
will present the science and facilities that will provide opportunities for the
particle physics community renew its commitment and maintain its leadership in
multimessenger science.
