astronomy

NGC 315

NGC 315 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 315 rather than just read about it. In short: NGC 315 is a massive elliptical galaxy in the constellation Pisces. Its velocity with respect to the cosmic microwave background is 4635 ± 22 km/s, which corresponds to a Hubble distance of 223.0 ± 15.7 Mly (68.36 ± 4.80 Mpc).

Key takeaways

NGC 315 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 315 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 315 from memory before moving on to harder problems.

Reference excerpt

NGC 315 is a massive elliptical galaxy in the constellation Pisces. Its velocity with respect to the cosmic microwave background is 4635 ± 22 km/s, which corresponds to a Hubble distance of 223.0 ± 15.7 Mly (68.36 ± 4.80 Mpc). In addition, eight non-redshift measurements give a distance of 208.58 ± 22.28 Mly (63.950 ± 6.830 Mpc). It was discovered by German-British astronomer William Herschel on September 11, 1784. The SIMBAD database lists NGC 315 as a LINER galaxy, i.e. a galaxy whose nucleus has an emission spectrum characterized by broad lines of weakly ionized atoms. According to A.M. Garcia, NGC 315 is the namesake of the NGC 315 Group (also known as LGG 14). This group contains 42 galaxies, including NGC 226, NGC 243, NGC 262, NGC 266, NGC 311, NGC 338, IC 43, IC 66, AND IC 69, among others. NGC 315, along with triple star NGC 313, and star NGC 316 are listed together as Holm 28 in Erik Holmberg's A Study of Double and Multiple Galaxies Together with Inquiries into some General Metagalactic Problems, published in 1937. The shape of NGC 315 is a triaxial ellipsoid that is highly prolate; its middle-to-long axis ratio is 0.854 and short-to-long axis ratio is 0.833. It has a stellar mass of 1.5×1012 M☉. At the center of the galaxy is a supermassive black hole with a mass of 3.0×109 M☉.

Illustrations

Worked examples

Example 1 — a first encounter with NGC 315

Start with the simplest possible case. Write down what NGC 315 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 315 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 315 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 315

In research: NGC 315 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 315 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 315 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1784, Discoveries by William Herschel, Elliptical galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 315 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 315 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 315 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 315 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 315 in simple terms?

Why does NGC 315 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 315?

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 315.