How big is the Moon’s biggest near-side crater, and why these numbers matter in lunar science

Curiosity isn’t just for the stars. It’s a mindset that makes lunar trivia click, which is exactly the kind of thing the LMHS NJROTC Academic Team might throw at you in a quiz or quick challenge. If you like numbers, maps, and a dash of mystery, you’re in good company. Let me take you through a recent lunar question in a way that also sharpens how you tackle similar topics on topics you’ll see around the Moon, geometry, and planetary science.

Here’s the question the team often features in its lunar round:

What is the diameter of the largest crater on the near side of the Moon?

A. 508 miles

B. 183 miles

C. 225 miles

D. 313 miles

The given answer in many study guides is B—183 miles. The short version is this: the near side of the Moon does have big craters, and you’ll see options that mix miles and kilometers. The long version? Let’s unpack it so you’re not tripped up by misreadings or a confusing blurb.

First, a quick map check: near side vs far side

• The Moon isn’t perfectly symmetrical. Its near side—the part we see from Earth—has bright maria, vast plains, and a lot of big craters. The far side hosts different craters and some colossal basins.

• The South Pole–Aitken Basin is famous for its enormous size, but it sits on the far side. If you’re looking for the largest crater strictly on the near side, you’re in a slightly different category than the “largest crater overall” conversation.

Now, about the numbers and names you might recall

• Tycho Crater: a well-known crater on the near side, with a diameter of about 53 miles (roughly 85 kilometers). It’s famous for its bright rays, not for being the largest, but it’s a handy reference point.

• Copernicus Crater: another widely studied near-side crater, with a diameter around 57 miles (about 93 kilometers). It’s often used in diagrams and photos from lunar missions.

• Clavius Crater: here’s a key one for sizing against the options. Clavius is quite large, with a diameter around 225 kilometers, which is about 140 miles. If you’re picturing big impact basins on the near side, Clavius is a go-to example.

All of those numbers help you compare, but here’s where the typical test question gets tricky: the options mix miles with a few that align with larger features, and the prompt sometimes mentions the far side basins to add a twist. If you only skim the choices, you could be swayed by a bigger number that’s not actually on the near side, or by a unit that isn’t directly comparable to the crater you’re meant to name.

So why does the 183-mile option show up?

• In some study prompts, the answer choices are designed to test your comfort with unit conversion and with distinguishing “crater” from “basin” and “sea” (lunar mare). 183 miles is about 295 kilometers, which is a plausible size for a large lunar crater in the right region. But that size isn’t a clean match for the best-known near-side craters when you’re thinking in widely taught examples.

• The note often added in longer explanations points out this distinction: some references mention the massive near-side basins or other formations, and others remind you that the South Pole–Aitken Basin, while enormous, is on the far side. The key learning moment isn’t a single number so much as recognizing how to navigate naming and geography under exam-like conditions.

What this teaches you about the kind of knowledge you’re building

• Geography literacy plus unit fluency matter. You’ll be asked to interpret a question, identify what’s being measured (crater diameter vs. basin width, near side vs. far side), and convert units when needed.

• It’s okay to pause and reframe. If you’re faced with a multiple-choice item that feels off, slow down, recall the map in your head, and compare the options against known benchmarks (Tycho for small, Clavius for a larger near-side example, South Pole–Aitken for far side context).

• Definitions matter. A “crater” is a circular depression from a impact event, whereas a “basin” might be thousands of kilometers across and is still a crater in the broad sense, but the scale and location change everything for the question at hand.

How to approach these lunar questions, in a way that’s practical for the team

• Create quick reference anchors. Keep a mental cheat sheet:

• Tycho: ~53 miles (≈85 km)

• Copernicus: ~57 miles (≈93 km)

• Clavius: ~140 miles (≈225 km)

• Far-side giant basins (like South Pole–Aitken): much larger, but outside the near side’s typical quiz focus

• Use unit checks. If a choice is in miles and you know a crater of interest is given in kilometers (or vice versa), convert one way in your head or on paper. A rough 2 miles ≈ 3.2 kilometers rule helps you sanity-check quickly.

• Read the prompt’s first impression. Does it talk about “near side” or “far side”? Does it say “crater” or “basin”? One word can steer you to the right line of thinking.

• Don’t get hung up on noise. Some options exist to trap you by mixing categories. The best move is to anchor on the core science: which feature exists where, and how big is it in known measurements.

Turning this into a learning habit for LMHS NJROTC students

Beyond memorizing numbers, this topic offers a nice window into how planetary science is studied and taught in a cadet-friendly format. You don’t need to be a telescope commander to succeed; you need curiosity, a method, and a few quick-reference facts you can lean on in a timed setting. The Moon is a perfect sandbox for training because it’s well-mapped, its features have common names, and the scale is easy to visualize once you’ve seen a few diagrams.

A few practical tips to carry forward

• Make a tiny field guide in your notebook. Sketch rough circles labeled Tycho, Copernicus, Clavius, and write their approximate diameters next to them. The act of drawing helps memory more than just reading numbers.

• Practice with quick conversions. If you see kilometers, convert to miles in your head (1 kilometer ≈ 0.621 miles). If you see miles, convert to kilometers (1 mile ≈ 1.609 kilometers). That fluency speeds up your thinking in a timed setting.

• Map the Moon in your mind. Picture the near side as a cheek with bright maria and large craters sprinkled along the limb. It helps you decide if a crater is near side or far side when wording mentions “on the near side.”

A light sidebar on curiosity and science

As you study, you’ll notice that the Moon isn’t just a boring rock in the sky. It’s a gateway to how scientists think about planetary surfaces, impact processes, and the history written in the crust. That sense of discovery—whether you’re comparing a famous crater’s size or exploring how basins form—keeps science alive. And that same sense translates well to leadership and teamwork in the NJROTC context: asking good questions, verifying facts, and explaining your reasoning clearly to others.

If you’re ever tempted to treat a lunar question like a speed bump, remember this: you’re not just trying to pick the right letter. You’re exercising a habit of mind. You’re learning to parse information, do a quick conversion, and situate a fact in a broader map of what you know. That’s the kind of skill that pays off in science clubs, classrooms, and future careers.

A few small, practical takeaways for your next quiz

• Read the prompt twice. First to get the gist, second to catch any hidden cues like “near side” or “not a crater.”

• Compare candidates by scale. If one option is clearly larger or smaller than the others, ask whether that scale makes sense for a near-side crater you’ve learned about.

• Practice with a handful of real-world data points. Knowing Tycho, Copernicus, and Clavius gives you quick yardsticks for other questions.

• Keep calm, stay curious, and connect the dots. The Moon is a perfect teacher for a cadet who loves maps, math, and a good mystery.

Bringing it back to the broader study of Moon science

This kind of quiz question isn’t just about naming the right crater. It’s a chance to practice scientific literacy: interpreting data, converting units, debating geography, and building a mental map of the lunar landscape. Those are the sorts of skills that can make a real difference, not just in a single round but across a cadet’s academic journey.

If you enjoy this blend of numbers, geography, and storytelling, you’ll find plenty of similar material in the topics your team explores. The Moon is a stepping stone—pun intended—to broader topics in astronomy, geology, and physics. And as you grow more confident with the language of size, space, and scale, you’ll notice your ability to think through complex questions sharpen in other subjects too.

Final thought

Questions like the one about the near-side crater diameter are more than trivia. They’re a compact way to practice critical thinking, unit fluency, and geographic literacy—skills that matter in anything you choose to study or do in the future. So the next time a lunar question lands on the page, take a breath, map the options in your head, and let your curiosity guide the way. The Moon has a lot to tell us, and with the right approach, you’ll hear every word clearly.