astronomy

NGC 3978

NGC 3978 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 3978 rather than just read about it. In short: NGC 3978 is a large intermediate spiral galaxy with a bar located in the constellation of Ursa Major. It is located 460 million light-years away from the Solar System and was discovered by William Herschel on March 19, 1790, but also observed by John Herschel on April 14, 1831.

Key takeaways

NGC 3978 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 3978 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 3978 from memory before moving on to harder problems.

Reference excerpt

NGC 3978 is a large intermediate spiral galaxy with a bar located in the constellation of Ursa Major. It is located 460 million light-years away from the Solar System and was discovered by William Herschel on March 19, 1790, but also observed by John Herschel on April 14, 1831. NGC 3978 has a luminosity class of II-III and it has a broad H II region which contains regions of ionized hydrogen. In addition, it is categorized as a LINER galaxy by SIMBAD, meaning its nucleus presents an emission spectrum which is characterized by broad lines of weakly ionized atoms. According to Vaucouleurs and Corwin, NGC 3978 and NGC 3975 form a galaxy pair with each other.

Supernovae Four supernovae have been observed NGC 3978:

SN 2003cq was discovered on March 30, 2003, by British astronomer Ron Arbour. It was located 32" east and 2.3" south of the nucleus with a magnitude of 17.1. This supernova was Type Ia. SN 2008I was discovered by astronomers P. Thrasher, W. Li, and Alex Filippenko as part of Lick Observatory Supernova Search (LOSS) on January 2, 2008. It was located 3.7" west and 10.4" north of the nucleus with magnitude of 19.1. The supernova was Type II which possibly resulted from a collapse of a massive star. SN 2020kay (Type II, mag. 18.5) was discovered by ATLAS on 15 May 2020. SN 2025ddb (Type II, mag. 18.566) was discovered by ATLAS on 2 March 2025.

References

Illustrations

Worked examples

Example 1 — a first encounter with NGC 3978

Start with the simplest possible case. Write down what NGC 3978 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 3978 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 3978 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 3978

In research: NGC 3978 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 3978 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 3978 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1790, Discoveries by William Herschel, IRAS catalogue objects, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 3978 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.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study NGC 3978 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 3978 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 3978 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 3978 in simple terms?

Why does NGC 3978 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 3978?

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 3978.