science

Lacus Somniorum

Lacus Somniorum is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Lacus Somniorum rather than just read about it. In short: Lacus Somniorum (Latin somniōrum, "Lake of Dreams") is a basaltic plain located in the northeastern part of the Moon's near side. It is located at selenographic coordinates 37.56° N, 30.8° E, and has a diameter of 424.76 kilometers.

Key takeaways

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

Reference excerpt

Lacus Somniorum (Latin somniōrum, "Lake of Dreams") is a basaltic plain located in the northeastern part of the Moon's near side. It is located at selenographic coordinates 37.56° N, 30.8° E, and has a diameter of 424.76 kilometers. The name is Latin for Lake of Dreams, a title given to this feature by Giovanni Riccioli. It is the largest of the lunar features designated Lacus. Lacus Somniorum is an irregular feature with complex, somewhat ill-defined borders. The surface has the same low albedo as the larger lunar mare found on the Moon, and its surface was formed by flows of basaltic lava. The mare material contains what is described as, "unusually bright and red mare soils" of somewhat uncertain composition. It possesses reddish hues and higher than normal albedo. There may be a lower abundance of ferrous materials in these basalts compared to the nearby Mare Serenitatis. The mare material shows a significant amount of contribution from deposited highland material. To the southwest this plain is joined to the Mare Serenitatis through a wide gap northwest of the crater Posidonius. This crater forms the western end of the southern border, which extends eastward to about longitude 41° before turning northwest. Along this southern border is attached the flooded crater Hall, and a 150-km-long rille named the Rima G. Bond for the small crater G. Bond south of Hall. The irregular eastern border comes close to the small crater Maury before continuing to the north until it reaches the crater remnant Williams. From there the edge continues to the west. A narrow border region separates the Lacus Somniorum from the smaller Lacus Mortis to the north. A buried crater with a 200 km diameter was detected in this locale by NASA's GRAIL experiment, forming part of the north wall of the mare. This strip of rough terrain includes the flooded impact craters Mason and Plana. Finally the lake curves back to the south, joining a region of rough terrain along the northern border of the Mare Serenitatis. In the southern half of this border area lies a rille system designated the Rimae Daniell, which consists of a set of graben oriented along a NNW-SSE direction. These were named for the crater Daniell, a small formation north of Posidonius that is encircled by the Lacus Somniorum. To the north of Daniell, near the northern edge of this feature, lies the small crater Grove.

Gallery

Illustrations

Worked examples

Example 1 — a first encounter with Lacus Somniorum

Start with the simplest possible case. Write down what Lacus Somniorum claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Lacus Somniorum 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 Lacus Somniorum 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 Lacus Somniorum

In research: Lacus Somniorum appears in science 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 Lacus Somniorum 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: Lacus Somniorum is common in secondary-school and first-year university syllabi. It links to neighbouring topics LQ05 quadrangle, Maria on the Moon, so understanding it makes those chapters shorter.
In everyday life: Look for Lacus Somniorum 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.

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How to study Lacus Somniorum in 20 minutes

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

Frequently asked questions

What is Lacus Somniorum in simple terms?

Why does Lacus Somniorum matter?

Because it connects several science 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 Lacus Somniorum?

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 Lacus Somniorum.