Comment by mock-possum | Hacker News Reader

Comment by mock-possum | Hacker News Reader

My fun little factoid about criticality is: sometimes it just happens naturally, on earth.

https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto...

> The natural nuclear reactor formed when a uranium-rich mineral deposit became inundated with groundwater, which could act as a moderator for the neutrons produced by nuclear fission. A chain reaction took place, producing heat that caused the groundwater to boil away; without a moderator that could slow the neutrons, however, the reaction slowed or stopped. The reactor thus had a negative void coefficient of reactivity, something employed as a safety mechanism in human-made light water reactors.

> After cooling of the mineral deposit, the water returned, and the reaction restarted, completing a full cycle every 3 hours. The fission reaction cycles continued for hundreds of thousands of years and ended when the ever-decreasing fissile materials, coupled with the build-up of neutron poisons, no longer could sustain a chain reaction.

What a wild story!

Interestingly, the -oid suffix usually refers to things that only resemble the thing, so an andr-oid is not really a man, a meteor-oid is not really a meteor, and fact-oid... might not really be a fact.

However the really amusing bit is that that everybody can agree--for different reasons--that:

> Here is a factoid: A factoid is a small fact.

The correct word would be a factlet, but factoid has been defacto taken its place. The fluidity of language, I suppose.

I wonder if anyone's done studies to measure and quantify the "distance" of slang (in years or generations) before an older person feels instinctive linguistic revulsion...

It's a continuous value, that is visibly different from zero almost immediately; children will experience it in a few contexts.

But is the collective noun for fully-grown factlets "facti" or "factodes"?

The octolets will get back to you.

I think I prefer factlet over factoid.

Yes, the -oid suffix is cognate with words like video and vision, referring to sight, so X-oid means something that looks like X.

Schizoid?

"Resembling schizophrenia but less severe"... seems to fit.

My recollection from many years ago is that Norman Mailer coined "factoid" to refer that what looked like facts, were offered as facts, but weren't facts.

Yes, both meanings exists in dictionaries.

Fortunately usage has consolidated. In my experience a factoid is generally intended to be true in (American?) English, but untrue in Swedish.

Aha, thank you for explaining why the American use of the word bothers me! I guess it became a false friend?

The letter u is a void. ;)

Similarly, 'factitious' sounds like it should be an antonym to 'fictitious', but it very much isn't. And 'factious' is another thing entirely.

It was a different time then

    approximately 1.7 billion years ago, during the Statherian period of the Paleoproterozoic, and continued for a few hundred thousand years, probably averaging less than 100 kW of thermal power during that time.

At least we now know how early life kept their devices charged.

Reply on news.ycombinator.com