What does collapsar mean?
A collapsar is an astronomical term denoting a star that has collapsed under its own gravity, typically producing an extremely dense compact remnant. The word was introduced in the 1930s by physicist Fritz Zwicky and astronomer Walter Baade, who speculated that a supernova explosion could leave behind such a collapsed core — an idea later confirmed with the discovery of neutron stars and black holes. Although once a serious scientific coinage, 'collapsar' has largely fallen out of everyday use among astronomers, who prefer terms like 'neutron star' or 'black hole.' It survives chiefly in historical discussions and in accounts of how scientists first conceived of these exotic objects. The word combines 'collapse' with the '-ar' suffix shared with other astronomical terms like 'pulsar' and 'quasar,' giving it a distinctly technical flavor. For general readers, encountering 'collapsar' offers a glimpse into the moment when astrophysics first grasped that stars could end their lives as objects stranger than anyone had imagined.
nounAn astronomical term for a massive star that has collapsed under its own gravity; historically used by Fritz Zwicky and Walter Baade in the 1930s to describe the stellar remnant now known as a neutron star or black hole.
- A star that has undergone gravitational collapse, especially one forming a compact remnant such as a neutron star or black hole.
"Zwicky and Baade proposed that a supernova explosion leaves behind a collapsar — a star compressed to extraordinary density."
"The dying giant would become a collapsar, its core crushed beyond ordinary density."
"Modern papers rarely use 'collapsar,' preferring 'black hole' or 'neutron star' instead."
Standard plural formation; rare outside technical literature.
"The galaxy's oldest collapsars date back billions of years."
Before astronomers said 'black hole,' they said 'collapsar' — the term was floated in the 1930s when Fritz Zwicky first imagined stars crushing themselves out of existence.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of collapsar
'Collapsar' was coined in English during the 1930s, combining the verb 'collapse' (from Latin 'collapsus,' past participle of 'collabi,' meaning 'to fall together') with the '-ar' suffix modeled on words like 'pulsar' and 'quasar.' The term is attributed to Fritz Zwicky, working with Walter Baade, who used it in proposing that massive stars end as collapsed remnants after supernova explosions. Its roots are thus Latinate, sharing ancestry with related words like 'lapse,' 'relapse,' and 'collapse' itself.
How collapsar is actually used
'Collapsar' is largely historical and technical, appearing mostly in older astronomical literature and popular accounts of the term's origin; it is rare in contemporary usage.
Easily confused with collapsar
A pulsar is a rapidly rotating neutron star that emits beams of radiation, whereas a collapsar refers more generally to a star that has collapsed under gravity.