What is the primary function of a radiotelescope?

The primary function of a radiotelescope is to gather radio waves emitted by celestial sources. This is crucial for the field of radio astronomy, as it allows scientists to detect and analyze the radio frequency emissions from various astronomical objects, such as stars, galaxies, and even remnants of supernovae. Unlike optical telescopes, which capture visible light, radiotelescopes are designed to detect a different range of electromagnetic radiation, specifically in the radio wavelengths. This ability to receive and interpret radio waves provides valuable insights into the physical characteristics and behavior of celestial bodies that may not be observable with other types of telescopes.

The other options, while they may involve aspects of astronomy, do not accurately reflect the primary role of a radiotelescope. Recording images of distant galaxies pertains more to optical telescopy or advanced imaging techniques, measuring the temperature of stars typically involves the analysis of their spectrum rather than the direct gathering of radio waves, and detecting gravitational waves is related to a completely different field of astrophysics that requires specialized instruments, not radiotelescopes.