THERE is a nagging suspicion abroad that the science of physics may be on its death bed.

A fundamental danger, as the Yale physicist Alan Chodos writes in American Scientist, is that experiments essential to testing new theories in physics will soon be beyond man's capacity to perform. Unable to mount experiments that would require energies comparable to that of the Big Bang genesis event, Dr. Chodos believes, growing numbers of physicists will be tempted to embrace grandiose but untestable theories, a practice that has more than once led science into blind alleys, dogma and mysticism.

In particular, Dr. Chodos worries that ''faddish'' particle physicists have begun to flock all too uncritically to a notion called ''superstring theory.'' That theory, which purports to interrelate all of nature's forces, including gravity, and all possible particles, is a kind of ''theory of everything,'' as Dr. Chodos expresses it - ''the Holy Grail of the Ultimate Theory.'' The great weakness of superstring theory, he contends, is that one of the key relationships it describes could be verified only at a scale of distances more than 100 quintillion quintillion times smaller than the particles that make up atomic nuclei. To imagine that anyone could ever measure anything at such an infinitessimal scale is just plain silly, he believes.

Deprived of the lifeblood of tangible experiment, physicists will ''wander off into uncharted regions of philosophy and pure mathematics,'' says Dr. Chodos, leaving true physics to wither.

His gloomy forecast is not the first of its kind.

In 1927, Max Born, one of the founders of the science of quantum mechanics, told visitors to Gottingen University that ''physics, as we know it, will be over in six months.'' But he was only partly right.