astronomy

GR 8 (galaxy)

GR 8 (galaxy) 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 GR 8 (galaxy) rather than just read about it. In short: GR 8 (also known as UGC 8091) is a gas-rich dwarf irregular galaxy. In 1995, Tolstoy et al. estimated its distance (with the Hipparcos correction of 1997 applied) to be approximately 7.9 million light-years (5.0×1011 AU) from Earth.

Key takeaways

GR 8 (galaxy) belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect GR 8 (galaxy) to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of GR 8 (galaxy) from memory before moving on to harder problems.

Reference excerpt

GR 8 (also known as UGC 8091) is a gas-rich dwarf irregular galaxy. In 1995, Tolstoy et al. estimated its distance (with the Hipparcos correction of 1997 applied) to be approximately 7.9 million light-years (5.0×1011 AU) from Earth. It is around 2.8 Mly from UGC 9128. It is still an open question whether it is a member of the Local Group or possibly the Virgo Cluster. GR 8 was discovered at the Lick Observatory using the 20-inch astrograph in either 1946, 1947, or 1951.

References

External links Irregular Galaxy GR 8: Footprint Galaxy DDO 155 picture (almost halfway down page)

Illustrations

Worked examples

Example 1 — a first encounter with GR 8 (galaxy)

Start with the simplest possible case. Write down what GR 8 (galaxy) 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 GR 8 (galaxy) 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 GR 8 (galaxy) 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 GR 8 (galaxy)

In research: GR 8 (galaxy) 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 GR 8 (galaxy) 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: GR 8 (galaxy) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Dwarf irregular galaxies, Principal Galaxies Catalogue objects, UGC objects, so understanding it makes those chapters shorter.
In everyday life: Look for GR 8 (galaxy) 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 GR 8 (galaxy) in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what GR 8 (galaxy) 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 GR 8 (galaxy) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is GR 8 (galaxy) in simple terms?

Why does GR 8 (galaxy) 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 GR 8 (galaxy)?

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 GR 8 (galaxy).