probe

A probe is an instrument or device designed to observe, measure, or obtain data about something that is difficult to reach directly. Probes are used across science, medicine, engineering, and space exploration, and can be either stationary sensors or mobile systems carried by a vehicle, instrument, or organism. The common purpose is to provide access to hidden or remote phenomena and to transmit information for analysis.

Space probes, or spacecraft probes, are uncrewed missions built to explore distant environments such as planets, moons, comets, or the outer solar system. They carry instruments to study geology, atmospheres, magnetic fields, radiation, and surfaces. Probes may fly by, enter orbit, or land. Examples include the Voyager and Pioneer programs, New Horizons, and Cassini. Many are powered by solar panels or radioisotope generators and communicate with Earth via radio.

Medical and laboratory probes are used to sample, image, or monitor tissues, fluids, or environments. Ultrasound probes convert electrical energy into sound waves for imaging; endoscopic probes guide cameras through body cavities; temperature, pH, or pressure probes measure physiological or environmental parameters. In biology and neuroscience, probes such as microelectrodes detect electrical or chemical activity in cells and tissues.

Electronic and engineering probes provide access to signals and voltages in circuits. Oscilloscope probes, logic probes, and current probes allow observation and troubleshooting without permanently altering hardware. The term probe is also used as a verb, meaning to investigate or test a hypothesis or system.

The concept spans practical instrumentation and exploratory missions, reflecting a general aim to extend human perception into inaccessible domains.