science

M109 Group

M109 Group is a science 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 M109 Group rather than just read about it. In short: The M109 Group (also known as the NGC 3992 Group or Ursa Major cloud) is a group of galaxies about 55 million light-years away in the constellation Ursa Major. The group is named after the brightest galaxy within the group, the spiral galaxy M109.

Key takeaways

M109 Group belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect M109 Group to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of M109 Group from memory before moving on to harder problems.

Reference excerpt

The M109 Group (also known as the NGC 3992 Group or Ursa Major cloud) is a group of galaxies about 55 million light-years away in the constellation Ursa Major. The group is named after the brightest galaxy within the group, the spiral galaxy M109.

Members The table below lists galaxies that have been consistently identified as group members in the Nearby Galaxies Catalog, the survey of Fouque et al., the Lyons Groups of Galaxies (LGG) Catalogue, and the three group lists created from the Nearby Optical Galaxy sample of Giuricin et al.

Galaxies frequently but not consistently listed as group members in the above references (i.e. galaxies listed in four of the above lists) include NGC 3631, NGC 3657, NGC 3733, NGC 3756, NGC 3850, NGC 3898, NGC 3985, NGC 3990, NGC 3998, NGC 4217, NGC 4220, UGC 6773, UGC 6802, UGC 6816, UGC 6922, and UGC 6969. The exact membership and the exact number of galaxies in the group is somewhat uncertain. Fouque et al. lists these galaxies as two separate groups named Ursa Major I North and Ursa Major I South, both of which were used to compile the above table. Most other references, however, identify this as a single group, as is specifically noted in the LGG Catalogue.

References

Illustrations

Worked examples

Example 1 — a first encounter with M109 Group

Start with the simplest possible case. Write down what M109 Group claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 M109 Group 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 M109 Group 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 M109 Group

In research: M109 Group appears in science 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 M109 Group 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: M109 Group is common in secondary-school and first-year university syllabi. It links to neighbouring topics M109 Group, Ursa Major, Ursa Major Cluster, so understanding it makes those chapters shorter.
In everyday life: Look for M109 Group 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 M109 Group in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what M109 Group 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 M109 Group out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is M109 Group in simple terms?

Why does M109 Group matter?

Because it connects several science 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 M109 Group?

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 M109 Group.