Puck (moon)

Key takeaways

Puck (moon) belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Puck (moon) to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Puck (moon) from memory before moving on to harder problems.

Reference excerpt

Puck is the sixth-largest moon of Uranus. It was discovered in December 1985 by the Voyager 2 spacecraft. The name Puck follows the convention of naming Uranus's moons after characters from Shakespeare's literary works, such as A Midsummer Night's Dream. The orbit of Puck lies between the rings of Uranus and the first of Uranus's large moons, Miranda. Puck is approximately spherical in shape and has diameter of about 162 km (101 mi). It has a dark, heavily cratered surface, which shows spectral signs of water ice.

Discovery and naming Puck—the largest inner moon of Uranus—was discovered from the images taken by Voyager 2 on 30 December 1985. It was given the temporary designation S/1985 U 1. The moon was later named after the character Puck who appears in Shakespeare's A Midsummer Night's Dream, a little sprite who travels around the globe at night with the fairies. In Celtic mythology and English folklore, a Puck is a mischievous sprite, imagined as an evil demon by Christians. It is also designated Uranus XV.

Physical characteristics

Puck is the largest inner moon of Uranus, orbiting inside the orbit of Miranda. It is intermediate in size between Portia (the second-largest inner moon) and Miranda (the smallest of the five major moons). Puck's orbit is located between the rings of Uranus and Miranda. Little is known about Puck aside from its orbit, radius of about 81 km (50 mi), and geometric albedo in visible light of approximately 0.10. Of the moons discovered by the Voyager 2 imaging team, only Puck was discovered early enough that the probe could be programmed to image it in some detail. One of the images had high enough resolution to constrain its shape in all three dimensions, which found that Puck has a shape consistent within errors to being a sphere. The ratio between its equatorial axes a/b is 0.93–1, and the polar axis c is at least 95% of b. Its surface is heavily cratered and is grey in color. There are three named craters on the surface of Puck, the largest being about 45 km (28 mi) in diameter. Observations with the Hubble Space Telescope and large terrestrial telescopes found water-ice absorption features in the spectrum of Puck. Little is known about the internal structure of Puck. It is probably made of a mixture of water ice and rocks, and may have been collisionally disrupted and reaccreted as a rubble pile. The presence of a 3.0 deep 3.0 micron feature attributed to the O-H stretching mode suggests that water ice or hydrated minerals are a common component on Puck's surface. Its surface is coated with a dark material similar to that found in the main rings. The dark material is probably made of rocks or radiation-processed organics; it is possible that material spiralling inwards from Uranus's μ ring coats Puck's leading hemisphere as well. Puck, as well as the other inner satellites of Uranus, is darker than the average inner Neptunian satellite, which could be either due to a higher level of solar irradiation at Uranus as opposed to Neptune, or a distinct composition. The absence of craters with bright rays implies that Puck is not differentiated, meaning that ice and non-ice components have not separated from each other into a core and mantle.

Named features Puck has three craters named Bogle, Butz, and Lob, which are named after mischievous spirits from Scottish, German, and British folklore respectively. Details about these craters are currently unknown.

See also Moons of Uranus Rings of Uranus

Notes

References

Citations

Sources Jacobson, R. A. (1998). "The Orbits of the Inner Uranian Satellites From Hubble Space Telescope and Voyager 2 Observations". The Astronomical Journal. 115 (3): 1195–1199. Bibcode:1998AJ....115.1195J. doi:10.1086/300263. Karkoschka, Erich (2001). "Voyager's Eleventh Discovery of a Satellite of Uranus and Photometry and the First Size Measurements of Nine Satellites". Icarus. 151 (1): 69–77. Bibcode:2001Icar..151...69K. doi:10.1006/icar.2001.6597. S2CID 121585538. Karkoschka, Erich (2001). "Comprehensive Photometry of the Rings and 16 Satellites of Uranus with the Hubble Space Telescope" (PDF). Icarus. 151 (1): 51–68. Bibcode:2001Icar..151...51K. doi:10.1006/icar.2001.6596. S2CID 121044546. Thomas, P.; Veverka, J.; Johnson, T.V.; Brown, Robert Hamilton (1987). "Voyager observations of 1985U1". Icarus. 72 (1): 79–83. Bibcode:1987Icar...72...79T. doi:10.1016/0019-1035(87)90121-7. Smith, B. A.; Soderblom, L. A.; Beebe, A.; Bliss, D.; Boyce, J. M.; Brahic, A.; Briggs, G. A.; Brown, R. H.; Collins, S. A. (4 July 1986). "Voyager 2 in the Uranian System: Imaging Science Results". Science. 233 (4759): 43–64. Bibcode:1986Sci...233...43S. doi:10.1126/science.233.4759.43. PMID 17812889. S2CID 5895824. Dumas, Christophe; Smith, Bradford A.; Terrile, Richard J. (2003). "Hubble Space Telescope NICMOS Multiband Photometry of Proteus and Puck". The Astronomical Journal. 126 (2): 1080–1085. Bibcode:2003AJ....126.1080D. doi:10.1086/375909. Marsden, Brian G. (January 16, 1986). "Satellites of Uranus and Neptune". IAU Circular (4159). Retrieved 2012-01-24. USGS/IAU (July 21, 2006). "Planet and Satellite Names and Discoverers". Gazetteer of Planetary Nomenclature. USGS Astrogeology. Retrieved 2012-01-24. French, Richard G.; Hedman, Matthew M.; Nicholson, Philip D.; Longaretti, Pierre-Yves; McGhee-French, Colleen A. (2024-03-15). "The Uranus system from occultation observations (1977–2006): Rings, pole direction, gravity field, and masses of Cressida, Cordelia, and Ophelia". Icarus. 411 115957. arXiv:2401.04634. Bibcode:2024Icar..41115957F. doi:10.1016/j.icarus.2024.115957. ISSN 0019-1035. Cartwright, Richard J.; Beddingfield, Chloe B.; Nordheim, Tom A.; et al. (June 2021). "The Science Case for Spacecraft Exploration of the Uranian Satellites: Candidate Ocean Worlds in an Ice Giant System". The Planetary Society Journal. 2 (3): 120. arXiv:2105.01164. Bibcode:2021PSJ.....2..120C. doi:10.3847/PSJ/abfe12. Jacobson, Robert A.; Park, Ryan S. (2025-02-03). "The Orbits of Uranus, Its Satellites and Rings, the Gravity Field of the Uranian System, and the Orientation of the Poles of Uranus and Its Satellites*". The Astronomical Journal. 169 (2): 65. Bibcode:2025AJ....169...65J. doi:10.3847/1538-3881/ad99d1. ISSN 0004-6256.{{cite journal}}: CS1 maint: ref duplicates default (link)

External links

Page that includes a reprocessed version of the Voyager 2 Puck image

Illustrations

Puck (moon): Named craters on Puck — Named craters on Puck

Worked examples

Example 1 — a first encounter with Puck (moon)

Start with the simplest possible case. Write down what Puck (moon) claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Puck (moon) before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Puck (moon) ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Puck (moon)

In research: Puck (moon) appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Puck (moon) in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Puck (moon) is common in secondary-school and first-year university syllabi. It links to neighbouring topics A Midsummer Night's Dream, Astronomical objects discovered in 1985, Moons of Uranus, so understanding it makes those chapters shorter.
In everyday life: Look for Puck (moon) outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Puck (moon) in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Puck (moon) means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Puck (moon) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Puck (moon) in simple terms?

Puck is the sixth-largest moon of Uranus. It was discovered in December 1985 by the Voyager 2 spacecraft.

Why does Puck (moon) matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Puck (moon)?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Puck (moon).