Size of Life - Hacker News

Posted by eatonphil 12/10/2025

2619 points | 277 commentspage 3

js8 12/11/2025|

I would like to play an open world game (like Minecraft) where 1 in-game meter equals 1 micrometer in the real world. That way, one could get a feeling about the scale of things.

mncharity 12/11/2025|

Hmm, perhaps with flying? When stuck on the ground, people's feel for size gets poorer as things get bigger (tall buildings, clouds, map distances). I think of having 4ish orders of magnitude available for visual reference in a classroom (cm to 10 m), plus less robustly 100 m and km in AR. At that micrometer per meter, a grain of salt towers over a city skyline - "nano view" in [1] (eep - a decade ago now - I was about to take another pass at it as covid hit).

[1] https://web.archive.org/web/20221007220513/http://www.clarif...

mncharity 12/11/2025||

Hmm, err, that could be misleading... 4ish for visible lengths in a large class. But especially in a small group, one can use reference objects of sand (mm) and flour (fine 100 um, ultrafine 10 um). The difference between the 100 um and 10 being more behavioral and feel (eg mouth feel) than unmagnified visible size. Thus with an outdoor view (for 100 m), one can use less-abstract "it's like that there accessible length" concrete-ish analogues across like 8 orders of magnitude. Or drop to 6, or maybe push for 9, as multiples of 3 nicely detent across SI prefixes.

mchinen 12/11/2025||

If you liked the first half of this site and want an extension, Cell Biology by the Numbers (2015, Milo, Phillips, https://book.bionumbers.org/) is great and has a similar intuition-building fun sense about size as well as various other measurements, including weight, time and energy at the atomic to micro-organism level.

krosaen 12/10/2025||

Neal.fun is good clean fun - my kids love it too. Neal, if you are listening, would pay for an ad-free version (I already bought you some coffees too).

sheepolog 12/10/2025||

Very cool. I was surprised that orangutans are described as being only 2 feet 9 inches tall, I think most are a bit larger. Maybe when sitting they're under 3 feet? From wikipedia:

"females typically stand 115 cm (45 in) tall and weigh around 37 kg (82 lb), while adult males stand 137 cm (54 in) tall and weigh 75 kg (165 lb). The tallest orangutan recorded was a 180 cm (71 in)."

LeifCarrotson 12/10/2025|

It's using the size of the ruler, matching the posture as shown in the image. A few keys over and there's a picture of a grizzly bear that says it is 1m or 3'4" tall. And maybe when it's on all fours, that's a typical measurement to the shoulders - its arm length, more or less.

That's much shorter than the human at 1.7m or 5'7". From just those numbers, you might think that a human would weigh more than a grizzly or take one in a fight: But when a bear stands on its hind legs, it's 2.4m/8' tall and can be 800 lbs, I'd have put a grizzly way further to the right.

macintux 12/10/2025||

> A highly social, relatively hairless bipedal ape that was once a nomadic hunter-gatherer, but has adapted to create websites

its_ethan 12/11/2025||

Maybe it's a stupid question, but how does the poliovirus "work"? Like at this scale, the DNA strand is still pretty visible and a decent-ish percentage of the polio virus in size.. is it just a ball with DNA inside and not much else? How does it pack enough DNA to replicate itself into it's own size at that scale?

zxexz 12/11/2025|

You’re pretty close actually. It’s a single strand of positive-sense RNA 7.5kb long, and a protein capsule. +ssRNA is treated as mRNA by the host and is directly translated into proteins.

bitpush 12/10/2025||

> Velociraptor > Smaller than usually depicted, the Velociraptor was actually only about the size of a turkey.

This is an interesting fact.

SubiculumCode 12/10/2025||

Why haven't I seen a Tardigrade with my eyeball? It seems like they are the size of a spot on a ladybug from the pics.

rsynnott 12/11/2025||

The spot on the ladybug is black against red, usually (there are many varieties); it's very conveniently highlighted. We're better at seeing "bold colour on bold colour" than "semi-translucent thing in water".

LeifCarrotson 12/10/2025||

Because you clearly haven't spent enough time closely looking at pond and river water!

Our local parks department has several annual events where they ask for volunteers to help perform benthic macroinvertebrate surveys. It basically amounts to meeting up at a local park with a couple people in waders dragging special nets along the bottom, dumping scoops of material into buckets and large, shallow, white trays, and others sitting at picnic tables with spoons, magnifying glasses, and muffin tins sorting out the critters that get caught in the nets.

The cool part is that at the end, you can score the creek based on the quantity and types of larvae that you find: Caddisfly, mayfly, and stonefly larvae are very sensitive to factors like runoff from agriculture and road salt, sediment, water oxygenation, and other factors, beetles, crayfish, dragonflies, and scuds are moderately tolerant, while leeches, worms, midges, and flies will grow in anything. Thousands of these surveys happen every year, so you can compare the relative frequency and quantity of various species and determine the relative health of the stream.

I don't know how many tardigrades you'll find just scooping 4-8mm nymphs and larvae by eye, but I've brought my microscope to a couple and put random droplets of water under a cover and slide: there are an astonishing number of tiny critters swimming around at any zoom level.

HelloUsername 12/10/2025|||

You have seen a tardigrade with the naked eye (without microscope), that's as large as a spot on a ladybug?

LeifCarrotson 12/11/2025||

No, sorry if that wasn't clear, I've not identified one by eye without a scope. Maybe your fine vision is better than mine, but all the tiniest things in a drop of water are just about indistinguishable without magnification. The kinds of water that have sufficient density to contain a tardigrade just look like they're full of grit, I don't think you could identify which speck was a tardigrade and which was just dirt.

Nymphs are larger (that's why they call them "macro" invertebrates), but it's always good to have at least a magnifying glass if not a loupe or microscope on site.

isametry 12/11/2025||

As a non-native speaker, TIL that "magnifying glass" and "loupe" are not synonyms. According to Wikipedia:

> [Loupes] generally have higher magnification than a magnifying glass, and are designed to be held or worn close to the eye.

myself248 12/11/2025|||

Do you set aside the tasty-looking ones and wrap it up with a seafood boil?

hamiecod 12/11/2025||

It makes me emotional when I think about where life started and what it evolved into. Life created so many different types of organisms, each having different features while maintaining the equilibrium of the planet. From bacteria, to massive dinosaurs, to tiny homosapiens who inevitably control the largest organisms.

bobnarizes 12/11/2025|

HUMAN

A highly social, relatively hairless bipedal ape that was once a nomadic hunter-gatherer, but has adapted to create websites. :)

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