science

Nirgal Vallis

Nirgal Vallis 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 Nirgal Vallis rather than just read about it. In short: Nirgal Vallis is a long river channel bordering the Coprates quadrangle and Margaritifer Sinus quadrangle of Mars at 28.4° south latitude and 42° west longitude. It is 610 km long and is named after Nergal, the Babylonian god of war and counterpart to the Roman god of war Mars.

Key takeaways

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

Reference excerpt

Nirgal Vallis is a long river channel bordering the Coprates quadrangle and Margaritifer Sinus quadrangle of Mars at 28.4° south latitude and 42° west longitude. It is 610 km long and is named after Nergal, the Babylonian god of war and counterpart to the Roman god of war Mars. Nirgal Vallis had a discharge of 4800 cubic meters/second. The western half of Nirgal Valles is a branched system, but the eastern half is a tightly sinuous, deeply entrenched valley. Nirgal Valles ends at Uzboi Vallis. Tributaries are very short and end in steep-walled valley heads, often called "amphitheater-headed valleys." The shape of these valley heads is like cirques on the Earth. Water from Nirgal Vallis contributed to a great flood that went through the rim of Holden Crater and helped form a lake in the crater. It is estimated that Nirgal Vallis had a discharge of 4800 cubic meters/second. Water from Nirgal Vallis was inbounded in Uzboi Vallis because the rim of Holden Crater blocked the flow. At a certain point the stored water broke through the rim of Holden and created a lake 200–250 m deep. Water with a depth of at least 50 m entered Holden at a rate that 5-10 times the discharge of the Mississippi River. Terraces and the presence of large rocks (tens of meters across) support these high discharge rates.

Nirgal Vallis and sapping Nirgal Valles is one of the longest valley networks on Mars. It is so large that it is found on two quadrangles. Scientists are not sure about how all the ancient river valleys were formed. There is evidence that instead of rain or snow, the water that formed the valleys originated under ground. One mechanism that has been advanced is sapping. In this case, the ground just gives away as water comes out. Sapping is common in some desert areas in America's Southwest. It forms alcoves and stubby tributaries; these features are visible in the pictures below of Nirgal Vallis taken with Mars Odyssey's THEMIS.

See also Geology of Mars – Geology of fourth planet from the Sun Groundwater on Mars – Water held in permeable ground Lakes on Mars – Former bodies of water on Mars List of quadrangles on Mars – Geographic subunits of the surface of Mars Vallis – Valley landform on other planets (mostly Mars) Uzboi-Landon-Morava (ULM) – Martian geological feature Water on Mars – Study of past and present water on Mars

References

External links

Nemiroff, R.; Bonnell, J., eds. (6 October 1997). "Surveyor At Mars". Astronomy Picture of the Day. NASA.

Illustrations

Worked examples

Example 1 — a first encounter with Nirgal Vallis

Start with the simplest possible case. Write down what Nirgal Vallis 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 Nirgal Vallis 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 Nirgal Vallis 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 Nirgal Vallis

In research: Nirgal Vallis 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 Nirgal Vallis 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: Nirgal Vallis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Coprates quadrangle, Margaritifer Sinus quadrangle, Valleys and canyons on Mars, so understanding it makes those chapters shorter.
In everyday life: Look for Nirgal Vallis 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 Nirgal Vallis in 20 minutes

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

Frequently asked questions

What is Nirgal Vallis in simple terms?

Why does Nirgal Vallis 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 Nirgal Vallis?

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 Nirgal Vallis.