astronomy

NGC 3905

NGC 3905 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 3905 rather than just read about it. In short: NGC 3905 is a barred spiral galaxy in the constellation of Crater. Its velocity with respect to the cosmic microwave background is 6,130±26 km/s, which corresponds to a Hubble distance of 294.9 ± 20.7 Mly (90.41 ± 6.34 Mpc).

Key takeaways

NGC 3905 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 3905 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 3905 from memory before moving on to harder problems.

Reference excerpt

NGC 3905 is a barred spiral galaxy in the constellation of Crater. Its velocity with respect to the cosmic microwave background is 6,130±26 km/s, which corresponds to a Hubble distance of 294.9 ± 20.7 Mly (90.41 ± 6.34 Mpc). However, six non-redshift measurements give a closer mean distance of 238.64 ± 20.80 Mly (73.167 ± 6.376 Mpc). It was discovered by English astronomer Andrew Ainslie Common in 1880. NGC 3905 is Seyfert II galaxy, i.e. it has a quasar-like nucleus with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, the host galaxy is clearly detectable.

LDC 824 group NGC 3905 is a member of the LDC 824 group of galaxies. This group contains 18 galaxies, including NGC 3702, NGC 3721, NGC 3722, NGC 3723, NGC 3763, NGC 3771, NGC 3791, NGC 3854, NGC 3858, IC 2910, and seven others.

Supernovae Three supernovae have been observed in NGC 3905:

SN 2001E (Type Ia, mag. 17.6) was discovered by LOTOSS (Lick Observatory and Tenagra Observatory Supernova Searches) on 5 January 2001. SN 2009ds (Type Ia, mag. 16.8) was discovered by Kōichi Itagaki on 28 April 2009. SN 2014V (Type II, mag. 18.4) was discovered by Pan-STARRS on 21 February 2014.

See also List of NGC objects (3001–4000)

References

External links Media related to NGC 3905 at Wikimedia Commons NGC 3905 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Illustrations

Worked examples

Example 1 — a first encounter with NGC 3905

Start with the simplest possible case. Write down what NGC 3905 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 3905 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 3905 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 3905

In research: NGC 3905 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 3905 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 3905 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1880, Barred spiral galaxies, Crater (constellation), so understanding it makes those chapters shorter.
In everyday life: Look for NGC 3905 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 3905 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 3905 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 3905 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 3905 in simple terms?

Why does NGC 3905 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 3905?

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 3905.