Prometheus (moon)

Key takeaways

Prometheus (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 Prometheus (moon) to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Prometheus (moon) from memory before moving on to harder problems.

Reference excerpt

Prometheus is an inner satellite of Saturn. It was discovered on 24 October 1980 from images taken by the Voyager 1 probe, and was provisionally designated S/1980 S 27. In late 1985 it was officially named after Prometheus, a Titan in Greek mythology. It is also designated Saturn XVI. Prometheus is extremely elongated, measuring approximately 137 km × 81 km × 56 km (85 mi × 50 mi × 35 mi). The surface is heavily cratered, giving it a similar appearance to nearby Epimetheus and Janus. It has several ridges and valleys and a number of impact craters of about 20 km (12 mi) diameter are visible. From its very low density and relatively high albedo, it is likely that Prometheus is a very porous icy body.

Interactions with F Ring and other moons Prometheus is a shepherd satellite for the inner edge of Saturn's narrow F Ring. Pandora orbits just outside the F Ring, and has traditionally been viewed as an outer shepherd of the ring; however, recent studies indicate that only Prometheus contributes to the confinement of the ring. Images from the Cassini probe show that Prometheus's gravitational influence creates kinks and knots in the F Ring as it shepherds material from it. The orbit of Prometheus appears to be chaotic, due to a series of four 121:118 mean-motion resonances with Pandora. The most appreciable changes in their orbits occur approximately every 6.2 years, when the periapsis of Pandora lines up with the apoapsis of Prometheus, as they approach to within approximately 1400 km. Prometheus is itself a significant perturber of Atlas, with which it is in a 53:54 mean-longitude resonance. Prometheus also participates in a 17:15 mean-motion resonance with Epimetheus, but only while it is on the outer orbit relative to Janus. No such configuration with Janus exists. Due to their gravitational interactions with the rings, Prometheus and Pandora are expected to crash into each other or Mimas in the next 20 million years.

Physical characteristics The surface of Prometheus can be distinguished into two types of terrain, both equally cratered and separated from each other by long scarps, one of which could be indicative of an exposed core section. This core section would make up roughly two-thirds of the total volume of Prometheus. Prometheus' elongated shape could be a result of the low-speed merging of several similar-sized bodies.

Gallery

Selected images

Animations

References

Notes

Citations

Sources Marsden, Brian G. (October 31, 1980). "Satellites of Saturn" (discovery). IAU Circular (3532). Retrieved 2011-12-29. Marsden, Brian G. (January 3, 1986). "Satellites of Saturn and Pluto" (naming the moon). IAU Circular (4157). Retrieved 2011-12-29. Renner, Stéfan F.; Sicardy, Bruno; French, Richard G. (March 2005). "Prometheus and Pandora: Masses and orbital positions during the Cassini tour". Icarus. 174 (1): 230–240. Bibcode:2005Icar..174..230R. doi:10.1016/j.icarus.2004.09.005. Spitale, J. N.; Jacobson, R. A.; Porco, C. C.; Owen, W. M. Jr. (2006). "The orbits of Saturn's small satellites derived from combined historic and Cassini imaging observations". The Astronomical Journal. 132 (2): 692–710. Bibcode:2006AJ....132..692S. doi:10.1086/505206. Thomas, P. C. (July 2010). "Sizes, shapes, and derived properties of the saturnian satellites after the Cassini nominal mission" (PDF). Icarus. 208 (1): 395–401. Bibcode:2010Icar..208..395T. doi:10.1016/j.icarus.2010.01.025. Archived from the original (PDF) on 2018-12-23. Retrieved 2015-09-04. USGS/IAU (July 21, 2006). "Planet and Satellite Names and Discoverers". Gazetteer of Planetary Nomenclature. USGS Astrogeology. Retrieved 2011-12-29. Thomas, P. C.; Helfenstein, P. (July 2020). "The small inner satellites of Saturn: Shapes, structures and some implications". Icarus. 344: 20. Bibcode:2020Icar..34413355T. doi:10.1016/j.icarus.2019.06.016. S2CID 197474587. 113355. Lainey, V.; Rambaux, N.; Cooper, N.; Dahoumane, R.; Zhang, Q. (February 2023). "Characterising the interior of five inner Saturnian moons using Cassini ISS data". Astronomy & Astrophysics. 670: 6. Bibcode:2023A&A...670L..25L. doi:10.1051/0004-6361/202244757. L25. Thomas, P. C.; Burns, J. A.; Hedman, M.; Helfenstein, P.; Morrison, S.; Tiscareno, M. S.; Veverka, J. (2013-09-01). "The inner small satellites of Saturn: A variety of worlds". Icarus. 226 (1): 999–1019. doi:10.1016/j.icarus.2013.07.022. ISSN 0019-1035. Ciarniello, Mauro; Filacchione, Gianrico; Nicholson, Philip D.; Hedman, Matthew M.; Charnoz, Sebastien; Cuzzi, Jeffrey N.; El Moutamid, Maryame; Hendrix, Amanda R.; Rambaux, Nicolas; Miller, Kelly E.; Mousis, Olivier; Baillié, Kevin; Estrada, Paul R.; Waite, J. Hunter (2024-09-17). "The Origin and Composition of Saturn's Ring Moons". Space Science Reviews. 220 (7): 72. doi:10.1007/s11214-024-01103-z. ISSN 1572-9672. Esposito, L. W.; De Stefano, M. (2018). "Space Age Studies of Planetary Rings". In Murray, Carl D.; Tiscareno, Matthew S. (eds.). Planetary Ring Systems: Properties, Structure, and Evolution. Cambridge Planetary Science. Cambridge: Cambridge University Press. pp. 3–29. doi:10.1017/9781316286791. ISBN 978-1-107-11382-4. Poulet, F.; Sicardy, B. (2001-04-01). "Dynamical evolution of the Prometheus--Pandora system". Monthly Notices of the Royal Astronomical Society. 322 (2): 343–355. Bibcode:2001MNRAS.322..343P. doi:10.1046/j.1365-8711.2001.04128.x. ISSN 0035-8711.

External links

Media related to Prometheus (moon) at Wikimedia Commons

"Cassini–Huygens: Multimedia-Videos / Soft Collision". NASA. Archived from the original on 29 October 2007. Prometheus slowly collides with the diffuse inner edge of Saturn's F ring ... pulls a streamer of material from the ring and leaves behind a dark channel. Prometheus Profile at NASA's Solar System Exploration site The Planetary Society: Prometheus 3-D anaglyph view of Prometheus

Illustrations

Worked examples

Example 1 — a first encounter with Prometheus (moon)

Start with the simplest possible case. Write down what Prometheus (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 Prometheus (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 Prometheus (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 Prometheus (moon)

In research: Prometheus (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 Prometheus (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: Prometheus (moon) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1980, Discoveries by Stewart A. Collins, Moons of Saturn, so understanding it makes those chapters shorter.
In everyday life: Look for Prometheus (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 Prometheus (moon) in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Prometheus (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 Prometheus (moon) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Prometheus (moon) in simple terms?

Prometheus is an inner satellite of Saturn. It was discovered on 24 October 1980 from images taken by the Voyager 1 probe, and was provisionally designated S/1980 S 27.

Why does Prometheus (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 Prometheus (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 Prometheus (moon).