Near-Earth objects
type: Concept
related: Close encounters

Opik theory
type: Concept
broader: Close encounters

Celestial mechanics
type: Concept
narrower: Close encounters

Close encounters
type: Concept
contributor: AAS Frey.Katie
modified: 2020-10-26T20:06:47.541Z
modified: 2020-10-26T20:06:31.917Z
broader: Celestial mechanics
definition: In a star cluster, coming across of two stars so closely that their orbits alter by their mutual gravitational attractions. As regards an asteroid or comet, a situation when it crosses the Moon's orbit and approaches the Earth with a risk of collision.
narrower: Opik theory
related: Near-Earth objects