Starry Messages: Searching for Signatures of Interstellar Archaeology
  Searching for signatures of cosmic-scale archaeological artifacts such as
Dyson spheres or Kardashev civilizations is an interesting alternative to
conventional SETI. Uncovering such an artifact does not require the intentional
transmission of a signal on the part of the original civilization. This type of
search is called interstellar archaeology or sometimes cosmic archaeology. The
detection of intelligence elsewhere in the Universe with interstellar
archaeology or SETI would have broad implications for science. For example, the
constraints of the anthropic principle would have to be loosened if a different
type of intelligence was discovered elsewhere. A variety of interstellar
archaeology signatures are discussed including non-natural planetary
atmospheric constituents, stellar doping with isotopes of nuclear wastes, Dyson
spheres, as well as signatures of stellar and galactic-scale engineering. The
concept of a Fermi bubble due to interstellar migration is introduced in the
discussion of galactic signatures. These potential interstellar archaeological
signatures are classified using the Kardashev scale. A modified Drake equation
is used to evaluate the relative challenges of finding various sources. With
few exceptions interstellar archaeological signatures are clouded and beyond
current technological capabilities. However SETI for so-called cultural
transmissions and planetary atmosphere signatures are within reach.
