Astronomy Glossary
Explore 128 astronomical terms with clear definitions and real-world examples
128
Total Terms44
⭐ Beginner58
⭐⭐ Intermediate26
⭐⭐⭐ AdvancedFilter Terms
O
Cosmology Universe
The observable Universe is the spherical region containing everything we can see or detect, limited by the finite speed of light and Universe's age.
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⭐⭐Astronomy Concepts
An occultation occurs when one object passes in front of another from an observer's perspective, temporarily blocking it.
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⭐⭐⭐Solar System
The Oort Cloud is a hypothetical spherical shell of icy planetesimals surrounding the Solar System at extreme distances (2,000-100,000 AU), serving as...
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Open clusters are loose groups of 100-1,000 young stars born together from the same molecular cloud, weakly gravitationally bound.
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Eccentricity (e) quantifies how elongated an orbit is, ranging from 0 (perfect circle) to 1 (parabola—unbound).
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Inclination is the angle between an object's orbital plane and a reference plane (usually the ecliptic for Solar System objects or galactic plane for ...
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