astronomy

NGC 2648

NGC 2648 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 2648 rather than just read about it. In short: NGC 2648 is an unbarred spiral galaxy located in the constellation Cancer. Its speed relative to the cosmic microwave background is 2,451 ± 19 km/s, which corresponds to a Hubble distance of 36.2 ± 2.6 Mpc (~118 million ly).

Key takeaways

NGC 2648 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 2648 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 2648 from memory before moving on to harder problems.

Reference excerpt

NGC 2648 is an unbarred spiral galaxy located in the constellation Cancer. Its speed relative to the cosmic microwave background is 2,451 ± 19 km/s, which corresponds to a Hubble distance of 36.2 ± 2.6 Mpc (~118 million ly). NGC 2648 was discovered by German-British astronomer William Herschel in 1784. The galaxies PGC 24469 and NGC 2648 are designated in Halton Arp's Atlas of Peculiar Galaxies as Arp 89. The luminosity class of NGC 2648 is I and it has a broad HI line. NGC 2648 is a retired galaxy, which is a galaxy in which star formation has practically ceased is said to be passive. However, some passive galaxies may still show faint emission lines similar to those of LINER galaxies. This is what a team of French and Brazilian astronomers discovered. It is from them that the name retired galaxy comes. To date, three non-redshift measurements give a distance of 34.333 ± 0.231 Mpc (~112 million ly), which is within the Hubble distance values.

See also List of NGC objects (2001–3000)

External links NGC 2648 at NASA/IPAC NGC 2648 at SIMBAD NGC 2648 at LEDA

References

Illustrations

Worked examples

Example 1 — a first encounter with NGC 2648

Start with the simplest possible case. Write down what NGC 2648 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 2648 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 2648 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 2648

In research: NGC 2648 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 2648 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 2648 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1784, Cancer (constellation), Discoveries by William Herschel, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 2648 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 2648 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 2648 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 2648 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 2648 in simple terms?

Why does NGC 2648 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 2648?

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 2648.