astronomy

Messier 85

Messier 85 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 Messier 85 rather than just read about it. In short: Messier 85 (also known as M85 or NGC 4382 or PGC 40515 or ISD 0135852) is a lenticular galaxy, or elliptical galaxy for other authors, in the Coma Berenices constellation. It is 60 million light-years away, and has a diameter of about 36.99 kiloparsecs (120,600 light-years) across.

Key takeaways

Messier 85 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Messier 85 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Messier 85 from memory before moving on to harder problems.

Reference excerpt

Messier 85 (also known as M85 or NGC 4382 or PGC 40515 or ISD 0135852) is a lenticular galaxy, or elliptical galaxy for other authors, in the Coma Berenices constellation. It is 60 million light-years away, and has a diameter of about 36.99 kiloparsecs (120,600 light-years) across. Pierre Méchain discovered M85 in 1781. It is within the outskirts of the Virgo Cluster, and is relatively isolated.

Properties M85 is extremely poor in neutral hydrogen and has a very complex outer structure with shells and ripples that are thought to have been caused by a merger with another galaxy that took place between 4 and 7 billion years ago, as well as a relatively young (<3 billion years old) stellar population on its centermost region, some of it in a ring, that may have been created by a late starburst. Like other massive, early-type galaxies, it has different populations of globular clusters. Aside from the typical "red" and "blue" populations, there is also a population with intermediate colors and an even redder population. It is likely transitioning from being a lenticular galaxy into an elliptical galaxy. While indirect methods imply that Messier 85 should contain a central supermassive black hole of around 100 million solar masses, velocity dispersion observations imply that the galaxy may entirely lack a central massive black hole. M85 is interacting with the nearby spiral galaxy NGC 4394, and a small elliptical galaxy called MCG 3-32-38. Compared to other early-type galaxies, M85 emits a relatively smaller proportion of X-rays.

Novae and Supernovae Two supernovae and one luminous red nova have been observed in M85:

SN 1960R (Type Ia, mag. 13.5), was discovered by Howard S. Gates on 20 December 1960, and independently discovered by Leonida Rosino on 18 January 1961. M85 OT2006-1 was discovered on the outskirts of the galaxy, by the Lick Observatory Supernova Search (LOSS) on 7 January 2006. It was classified as a luminous red nova, the first to be identified as such. SN 2020nlb (Type Ia, mag. 17.436) was discovered by the ATLAS telescope in Hawaii on 25 June 2020. This supernova got as bright as magnitude 12.

Illustrations

Worked examples

Example 1 — a first encounter with Messier 85

Start with the simplest possible case. Write down what Messier 85 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 Messier 85 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 Messier 85 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 Messier 85

In research: Messier 85 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 Messier 85 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: Messier 85 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1781, Coma Berenices, Discoveries by Pierre Méchain, so understanding it makes those chapters shorter.
In everyday life: Look for Messier 85 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 Messier 85 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Messier 85 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 Messier 85 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Messier 85 in simple terms?

Why does Messier 85 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 Messier 85?

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 Messier 85.