astronomy

NGC 1947

NGC 1947 is a astronomy 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 NGC 1947 rather than just read about it. In short: NGC 1947 is a peculiar lenticular galaxy in the constellation Dorado. The galaxy lies about 50 million light years away from Earth, which means, given its apparent dimensions, that NGC 1947 is approximately 75,000 light years across.

Key takeaways

NGC 1947 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect NGC 1947 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 1947 from memory before moving on to harder problems.

Reference excerpt

NGC 1947 is a peculiar lenticular galaxy in the constellation Dorado. The galaxy lies about 50 million light years away from Earth, which means, given its apparent dimensions, that NGC 1947 is approximately 75,000 light years across. It was discovered by James Dunlop on November 5, 1826.

Characteristics The galaxy is characterised by the presence of dust lanes across the minor axis of the galaxy, indicating it is a polar-ring galaxy. The galaxy has one central dust lane while three more less pronounced lanes are visible which look like concentric rings. Although it is categorised as a lenticular galaxy, it lacks a disk, having thus more in common with elliptical galaxies. Molecular gas has been detected around the nucleus of the galaxy with an estimated hydrogen mass of 4.2×108 M☉. The gas rotates in an axis perpendicular to that of the stars of the galaxy, but in its inner region it is warped. The kinematics suggest that the dust and gas have an external origin, probably accreted from a gas-rich galaxy, as there is a lack of tidal tails that would indicate it is as a result of an unequal mass merger with a disk galaxy. The nucleus of the galaxy has been found to be active and it is categorised as a LINER. The most accepted theory for the energy source of active galactic nuclei is the presence of an accretion disk around a supermassive black hole.

Nearby galaxies NGC 1947 is the brightest galaxy in the NGC 1947 group, which also includes the galaxies ESO 085–065, ESO 085–088, and ESO 086–010. This group lies close to the Dorado Group, and is part of the Southern Supercluster.

References

External links

NGC 1947 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Illustrations

Worked examples

Example 1 — a first encounter with NGC 1947

Start with the simplest possible case. Write down what NGC 1947 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 NGC 1947 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 NGC 1947 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 NGC 1947

In research: NGC 1947 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 NGC 1947 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: NGC 1947 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1826, Discoveries by James Dunlop, Dorado, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 1947 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 NGC 1947 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 1947 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 NGC 1947 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 1947 in simple terms?

Why does NGC 1947 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 NGC 1947?

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 NGC 1947.