Larissa Moon: Learn About Neptune's Natural Satellite

Shirin Biswas
Nov 04, 2022 By Shirin Biswas
Originally Published on Dec 29, 2021
Edited by Jacob Fitzbright
Fact-checked by Niyati Parab
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Read these Larissa moon facts to learn about this large moon and how it got its name!

Discovered in 1981, it was not until later that this moon got the name that it is now known by.

Larissa was observed in ground-based research work through telescopes in the year 1981 by a number of scientists, but it was when Voyager 2 came across this moon that its existence was substantiated with proper proof!

This cratered and rugged-looking moon is one of the largest that orbits around Neptune and hence is a matter of interest for many scientists. The moon was given many names before it came to be known as Larissa.

The first name to be assigned to it was S/1981 N 1 when it was discovered by H. Reitsema, W. Hubbard, L. Lebofsky, and D. Tholen.

The next name was S/1989 N 2 when the Voyager 2 flyby captured pictures of the moon. The next name was Neptune VII before the beautiful moon was finally named after the Greek nymph, Larissa.

Physical Features Of Larissa Moon

Larissa is one of the many moons that Neptune is known to have. To date, as many as 14 of Neptune's moons have been discovered by scientists from Earth.

  • There may or may not be more moons or natural satellites of this planet, but Larissa sure is a forerunner and quite famous as well.
  • Larissa is a natural satellite that is famous due to the fact that due to its diameter it is the fourth largest of Neptune's satellites discovered to the present date. Even though it was first discovered by scientists and astronomers through ground-based work in the year 1981, the first pictorial evidence of its existence only came through in 1989, when Voyager 2 accidentally - yet fortunately - stumbled across this natural satellite. The pictures received through Voyager 2 suggest that this natural satellite is heavily cratered.
  • It is speculated that Larissa may have been created through the perturbations of Triton.
  • Triton is another natural satellite of Neptune that has given rise to many other moons which look much like a rubble-pile. Larissa's rugged appearance and its seemingly irregular orbit suggest that it may have been created from the remnants of the original satellites of the planet Neptune.
  • Larissa may have thus been a product of its capture in a very eccentric initial orbit. However, whether or not Larissa truly is a product of or made up of remnants of Neptune's original satellites is a matter of speculation which can only be settled through further study.
  • It is one of the inner satellites of Neptune.

Surface Temperature And Conditions Of Larissa Moon

Larissa circles around the planet, just like the 13 other Neptunian satellites.

  • Originally named Neptune VII, it has an estimated temperature of around 51 K. This means that the temperature of this moon of Neptune is around -367.87 F (-222.15 C).
  • The surface conditions of this moon, according to the pictures captured by NASA's spacecraft, suggest a rugged terrain.
  • This moon of Neptune is cratered and very irregular in shape. This is quite different from Earth's moon, which is somewhat regular in shape in spite of having many craters.
  • The craters may have been a result of the fact that Larissa may have been created from the remains of Neptune's initial moons which came apart.
  • There are speculations that Neptune's tidal forces could create a planetary ring out of Larissa, which will definitely be a very interesting phenomenon. Another interesting fact about Larissa is that it does not have a completely circular orbit. Larissa's orbit is somewhat spiral. This means that the surface gravity and Neptune's tidal pull may result in a clash between the moon and its planet, which would make it into a planetary ring.
  • It is a relatively short distance from Neptune's clouds.
Neptune's smallest moon is called Hippocamp!

The Discovery Of Larissa Moon

The first discovery of Larissa was made by H. Reitsema, W. Hubbard, L. Lebofsky, and D. Tholen. The discovery was made by ground-based telescopes and the name given to the moon Larissa was S/1981 N 1.

The name was changed to S/1989 N 2, after Voyager 2 stumbled across it. It was named Neptune VII before finally being named after a Greek nymph named Larissa.

  • The naming of Neptune VII as Larissa was based on the fact that the Greek God Poseidon, or Roman God Neptune, was loved by a nymph named Larissa.
  • The discovery of Larissa by Voyager 2 was purely based on chance. The spacecraft was launched on August 20, 1977, with the intention of studying planets such as Uranus and Neptune, but the main focus was the study of Jupiter and Saturn, each ring of Saturn and the many moons that these planets possessed. The fact that Larissa's orbit would come in the way of Voyager 2 is purely a matter of luck as the observatory at NASA observed a moon that was viewed from ground years ago!

How far is Larissa moon from Earth?

There is no accurate information regarding this moon's distance from Earth, but it is 30,300 mi (48,763 km) away from Neptune's clouds which can only mean that this cratered and irregularly shaped moon is far away from us! Here are some more facts about the Larissa moon for you!

  • Larissa has an orbital period of around 13 hours and 18 minutes.
  • It circles the planet in the same direction in which Neptune rotates.
  • No signs of geological changes can be observed from the pictures taken by Voyager 2.
  • The surface area of Neptune VII or Larissa moon is around 45,651.55 sq mi (118,236.97172 sq km)!
  • Larissa may become a planetary ring if the moon's spiral orbit and Neptune's tidal forces cause a collision!
  • Larissa is said to be made of rubble!
  • Neptune has 14 moons: Naiad, Psamathe, Halimede, Galatea, Larissa, S/2004 N1 (which is yet to receive an official name), Proteus, Thalassa, Triton, Despina Nereid, Sao, Laomedeia, and Neso.

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Written by Shirin Biswas

Bachelor of Arts specializing in English Language and Literature

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Shirin BiswasBachelor of Arts specializing in English Language and Literature

With a degree in English from Amity University, Noida, Shirin has won awards for oratory, acting, and creative writing. She has a wealth of experience as an English teacher, editor, and writer, having previously worked at Quizzy and Big Books Publishing. Her expertise lies in editing study guides for children and creating engaging content.

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Fact-checked by Niyati Parab

Bachelor of Commerce

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Niyati ParabBachelor of Commerce

With a background in digital marketing, Niyati brings her expertise to ensure accuracy and authenticity in every piece of content. She has previously written articles for MuseumFacts, a history web magazine, while also handling its digital marketing. In addition to her marketing skills, Niyati is fluent in six languages and has a Commerce degree from Savitribai Phule Pune University. She has also been recognized for her public speaking abilities, holding the position of Vice President of Education at the Toastmasters Club of Pune, where she won several awards and represented the club in writing and speech contests at the area level.

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