Thalassa (moon) facts for kids
 Naiad or Thalassa as seen by Voyager 2 (smearing has caused excessive elongation) |
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| Discovery | |
|---|---|
| Discovered by | Richard J. Terrile and Voyager Imaging Team |
| Discovered in | September 1989 |
| Orbital facts | |
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| Distance from Neptune | 50 075 ± 1 km |
| Orbit shape | 0.0002 ± 0.0002 |
| Time to orbit Neptune | 0.31148444 ± 0.00000006 d |
| Orbit tilt | 0.21 ± 0.02° (to Neptune equator) 0.21° (to local Laplace plane) |
| Is a moon of | Neptune |
| Physical facts | |
| Dimensions | 108×100×52 km |
| Mass | ~3.5×1017 kg (based on assumed density) |
| Mean density | ~1.2 g/cm3 (estimate) |
| Rotation time | assumed synchronous |
| Axis tilt | ~zero presumably |
| Reflectivity | 0.09 |
| Surface temp. | ~51 K mean (estimate) |
| Atmosphere | none |
Thalassa is a moon that orbits the planet Neptune. It is also known as Neptune IV. It is the second moon closest to Neptune.
The name "Thalassa" comes from Greek mythology. Thalassa was a daughter of Aether and Hemera. The word "Thalassa" also means "sea" in the Greek language.
Discovery of Thalassa
Thalassa was found using pictures taken by the Voyager 2 space probe. It was discovered sometime before mid-September 1989.
When it was first found, it was given the temporary name S/1989 N 5. The discovery was officially announced on September 29, 1989. The pictures used to find it were taken over 11 days, meaning it was likely seen before September 18. The moon was officially named Thalassa on September 16, 1991.
About Thalassa's Shape
Thalassa is not shaped like a perfect sphere (a round ball). It has an unusual shape that scientists find hard to explain. It does not show any signs of geological changes, which means its surface has not been changed by things like volcanoes or earthquakes.
Images for kids
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This picture shows how Naiad (red path) moves around Neptune. The view follows Thalassa (yellow dot) as it orbits.
See also
In Spanish: Talasa (satélite) para niños
