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ʻOumuamua
The first confirmed object observed arriving from interstellar space.
- classification
- Interstellar object
- system
- Passing through the Solar System
ʻOumuamua passed through the inner Solar System in 2017. Limited observations constrained its motion and unexplained non-gravitational acceleration, but its exact shape, composition and origin remain unresolved; proposed explanations (e.g. outgassing comet, exotic hydrogen iceberg, or other natural mechanisms) remain debated and no consensus has been reached.
- Class
- Interstellar object
- Location / system
- Passing through the Solar System
- Distance
- Outbound on a hyperbolic trajectory
Only values with an established scientific consensus are listed. Where a quantity is uncertain or model-dependent, it is discussed in the sections below rather than stated as data.
Overview (starter entry, expanded review pending)
ʻOumuamua passed through the inner Solar System in 2017. Limited observations constrained its motion and unexplained non-gravitational acceleration, but its exact shape, composition and origin remain unresolved; proposed explanations (e.g. outgassing comet, exotic hydrogen iceberg, or other natural mechanisms) remain debated and no consensus has been reached.
Trajectory, imaging and spectroscopy
ʻOumuamua's orbit or trajectory is measured over time; reflected-light observations constrain rotation, shape and composition where the signal permits.
- What remains least constrained about ʻOumuamua?Composition, internal structure, formation history or local environment can require different observations and may remain model-dependent.
Items above are unresolved. Hypotheses are labelled as such and are not presented as confirmed findings.
NASA // verified 28 September 2026
NASA/JPL // verified 28 September 2026