astronomi

Astronomi, commonly called astronomy, is the natural science that studies celestial objects and phenomena. It aims to understand the properties, motions, and origins of objects from planets and stars to galaxies and the universe as a whole. The field combines systematic observations with theoretical models and computer simulations to explain how cosmic systems form, evolve, and interact across vast distances and timescales.

Historically, astronomy began with naked-eye observations in ancient cultures. The invention of the telescope in the 17th century transformed astronomy into a quantitative science and gave rise to astrophysics. The discovery of universal expansion and the development of cosmology in the 20th century further broadened the scope.

Major subfields include planetary science, stellar astronomy, galactic and extragalactic astronomy, and cosmology. Observational astronomy uses telescopes and detectors across the electromagnetic spectrum—optical, radio, infrared, ultraviolet, X-ray, and gamma-ray—often placed both on the ground and in space. Theoretical astronomy builds models of stellar interiors, galactic dynamics, and the evolution of the universe. Subfields also include astroparticle physics, gravitational-wave astronomy, and exoplanet science.

Practitioners work in universities, research institutes, observatories, and space agencies. Data analysis, instrumentation, and simulation are essential tools, and collaboration across disciplines underpins progress. The field relies on international cooperation for large facilities and long-term surveys.