radiohavaintojen

Radiohavaintojen, or radio observations, refer to the detection and study of radio waves emitted by astronomical objects. In contrast to optical observations, radio astronomy uses radio frequencies ranging from about 30 megahertz to several hundred gigahertz. These observations are carried out with radio telescopes, which can be single dishes, arrays, or interferometers, allowing the collection of data over a wide range of angular resolutions.

The field emerged in the 1930s, following the groundbreaking detection of cosmic radio waves by Karl Seyfert and later with the discovery of the cosmic microwave background radiation in 1964. Since then, radio astronomy has revealed phenomena invisible in other wavelengths, such as pulsars, solar bursts, and the detailed structure of radio galaxies. Interferometric arrays like the Very Large Array and the Atacama Large Millimeter/submillimeter Array combine signals from multiple antennas to produce high‑resolution images.

Radio observations also serve practical applications; for instance, radar astronomy probes the surface of nearby asteroids, while radio occultation experiments provide atmospheric data for planetary missions. Advances in digital signal processing and software-defined radio continue to improve sensitivity and data throughput, enabling projects such as the Square Kilometre Array, which aims to probe the early universe and test fundamental physics.