astronomy

NGC 973

NGC 973 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 973 rather than just read about it. In short: NGC 973 is a giant spiral galaxy located in the constellation Triangulum. It is located at a distance of circa 200 million light-years from Earth, which, given its apparent dimensions, means that NGC 973 is about 230,000 light years across.

Key takeaways

NGC 973 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 973 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 973 from memory before moving on to harder problems.

Reference excerpt

NGC 973 is a giant spiral galaxy located in the constellation Triangulum. It is located at a distance of circa 200 million light-years from Earth, which, given its apparent dimensions, means that NGC 973 is about 230,000 light years across. It was discovered by Lewis Swift on October 30, 1885.

Characteristics NGC 973 is seen edge-on, with an inclination of nearly 90°. Its bulge is shaped like a box or peanut. The subtraction of axisymmetric components from the profile of the galaxy showed that its bulge has an X-like morphology, which indicates the presence of a bar. A prominent dust lane runs across the galaxy. The galaxy kinematics revealed that the northeast side is the approaching one and the southwest is receding. The disk appears flat, without warps. The total hydrogen mass of the galaxy is estimated to be about 9×109 M☉, and the total dust mass is estimated to be 1.4×108 M☉, with clumpy distribution. Faint emission from gas lying outside the plane of the galaxy was detected in H-alpha, correlated with the galactic disk and halo. The nucleus of NGC 973 appears to be active based on its emission. It is categorised as a Type II Seyfert galaxy. 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 973 is the largest galaxy in a galaxy group known as the NGC 973 group. The NGC 973 group is one of the largest galaxy groups of the Perseus–Pisces Supercluster, with at least 39 galaxies identified as its members. Other members of the group include NGC 917, NGC 931, NGC 940, NGC 969, NGC 974, NGC 978, NGC 987, NGC 983, NGC 1060, NGC 1066, NGC 1067, and UGC 2105. NGC 973 forms a pair with IC 1815, which lies 4.6 arcminutes to the south. A small satellite was discovered in HI imaging near the northeast edge of the disk of NGC 973, with no optical counterpart.

Supernova One supernova has been observed in NGC 973:

SN 2025agyg (Type Ia, mag. 19.72) was discovered by Pan-STARRS on 24 November 2025.

Gallery

References

External links Media related to NGC 973 at Wikimedia Commons

NGC 973 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images NGC 973 on SIMBAD

Illustrations

Worked examples

Example 1 — a first encounter with NGC 973

Start with the simplest possible case. Write down what NGC 973 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 973 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 973 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 973

In research: NGC 973 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 973 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 973 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1885, Discoveries by Lewis Swift, NGC objects, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 973 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 973 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 973 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 973 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 973 in simple terms?

Why does NGC 973 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 973?

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 973.