A protostar is a celestial object in the dramatic early stages of stellar birth, representing the critical transition from a cold, dark cloud to a blazing star. This cosmic embryo forms when gravity causes a dense region within a molecular cloud to collapse, heating up as it contracts but not yet hot enough (10 million Kelvin) in its core to ignite the nuclear fusion that defines true stars.</p><p>During this phase, lasting roughly 100,000 to 10 million years depending on the protostar's mass, the object glows primarily from gravitational energy as it continues shrinking. Protostars are often shrouded in thick cocoons of dust and gas, making them invisible to optical telescopes but detectable through infrared observations that penetrate these veils.</p><p>Famous examples include the protostars within the Orion Nebula, where the Hubble Space Telescope has captured stunning images of these stellar nurseries in action. The nearby Bok globules, like Barnard 68, contain protostars in various developmental stages. Even our own Sun began as a protostar approximately 4.6 billion years ago within a similar collapsing cloud.</p><p>First systematically studied in the 1960s using radio telescopes, protostars represent one of astronomy's most dynamic processes, where gravity sculpts the universe's fundamental building blocks—stars that will eventually forge the heavy elements essential for planets and life.