Fun Fact Thread! (previously fun fact for the day, not limited to 1 per day anymore.)

[DDE]

20 minutes ago, Hyperspace Industries said:

South Africa has a load of uranium, the whole north cape province is basically one giant uranium ore deposit. There are over 20 uranium mines there.

This allowed us to in (I think,  (the only time reference my dad gave was during apartheid)) the 80’s build our own nukes, from our own uranium!

Yes. SA became the only country to have ever produced nuclear weapons, and have then given them up.

[DDE]

In 1703, travelling with Peter I a Dutchman named Cornelis de Bruijn recorded with absolute puzzlement a plethora of elephant teeth found by the village of Kostyonki in Southern Russia. At the time, the best explanation the Tsar was able to come up with was... war elephants lost by the army of Alexander the Great 

The truth is far woolier.

Spoiler

 

[Admiral Fluffy]

Kaboom?

 

[Beamer]

Discovered by Edwin Hall in 1879, the Hall Effect is "the production of a voltage difference (the Hall voltage) across an electrical conductor that is transverse to an electric current in the conductor and to an applied magnetic field perpendicular to the current." (quoted from wikipedia).

The effect has many different applications (such as sensors for rotation speed, fluid flow, current and pressure). The main advantage of Hall sensors over optical and electromechanical sensors is that they are immune to dust, dirt, mud and water and can be used to create various 'contactless' sensors for measurements that would require contact points using other means.

The consequences of the effect also have a relationship to star formation where it influences the gravitational collapse of proto-stars. As if that wasn't enough it has also been used in rocket engines since 1971 in the Hall Effect Thruster, a type of Ion engine, which is intended to be used for the Artemis program's Lunar Gateway as a thruster for the station's orbital corrections. Hall Effect Thrusters require a lot of electric current and (as Ion engines go) have a low thrust but an incredibly high ISP which makes them useful as thrusters on things like geostationary sats to make small orbital adjustments.

Among the many other applications it can be used to create a sensor that generates a current that is dependent on the strength of a magnetic field - so with some calibration it can be used to measure the distance between the sensor and the magnet creating that magnetic field. Very recently some mechanical keyboard manufacturers have started using this effect in their keyboards to create contactless key sensors. Not only does this get rid of the wear-and-tear (and dust/dirt) sensitive component in a typical Cherry MX mechanical key setup, but it essentially creates an analog measurements of the key-presses. In other words, the keyboard doesn't only know you pressed a key, but also how far/fast you pressed it. This can be used in gaming as analog control for things like a gas pedals and steering control and also allows for precise control of how far a key needs to be pressed to count as a key-press, and how far the key needs to be raised again before allowing a follow-up key-press - with precision down to 0.1mm movements.

I'm a sucker for mechanical keyboards and bleeding-edge tech, and my keyboards (as well as mice) suffer the absolute worst punishing usage patterns of continued typing during my work day followed by multi-hour gaming sessions in the evenings, spiced up with cigarette smoke and cookie crumbs. I can wear out a top-brand Cherry Red keyboard in a frighteningly short time. So yes, this looked extremely interesting to me and I shelled out the somewhat exorbitant cost to pre-order me one of these beauties from Wooten, expected to arrive in April this year. I can't wait to play around with it.

An interesting article about keyboards like this can be found on a recent ArsTechnica post where they spotlight someone who made a DIY version of these keys using a 3D printer, neodymium magnets and Hall sensors: https://arstechnica.com/gadgets/2022/02/diy-mechanical-keyboard-switch-lets-you-set-its-actuation-point/

 

[kerbiloid]

Air is 80%N +20% O.

I.e. 4N + O

I.e. N₂ + N₂O

And it makes it funny.

[StrandedonEarth]

4 hours ago, kerbiloid said:

Air is 80%N +20% O.

I.e. 4N + O

I.e. N₂ + N₂O

And it makes it funny.

And it gives my giggling an extra boost!

[JoeSchmuckatelli]

On 2/25/2022 at 10:40 AM, Beamer said:

the keyboard doesn't only know you pressed a key, but also how far/fast you pressed it.

That has potential to be a game changer!

 

 

 

 

 

 

 

(get it?)

[StrandedonEarth]

46 minutes ago, JoeSchmuckatelli said:

That has potential to be a game changer!(get it?)

Quite literally!

And I didn't see the (get it?)  until I was trimming the quote...

[DDE]

You may have heard that the Soviets built a dozen titanium-hulled submarines. You may have also heard that the result was annoyingly expensive, hence it remains an unmatched feat.

This is mostly because welding absolutely anything made of titanium requires a vacuum or an argon atmosphere, which is very much akin to an EVA.

And given how metals interact in seawater, on a titanium submarine, nearly everything has to be made of titanium. These days, titanium seems mostky confined to reactor machinery.

[Guest]

12 minutes ago, DDE said:

You may have heard that the Soviets built a dozen titanium-hulled submarines. You may have also heard that the result was annoyingly expensive, hence it remains an unmatched feat.

This is mostly because welding absolutely anything made of titanium requires a vacuum or an argon atmosphere, which is very much akin to an EVA.

And given how metals interact in seawater, on a titanium submarine, nearly everything has to be made of titanium. These days, titanium seems mostky confined to reactor machinery.

Woah!

That's really cool!

[Admiral Fluffy]

21 minutes ago, DDE said:

You may have heard that the Soviets built a dozen titanium-hulled submarines. You may have also heard that the result was annoyingly expensive, hence it remains an unmatched feat.

Corresponding wikipedia article:https://en.wikipedia.org/wiki/Alfa-class_submarine

A college has an on-site nuclear reactor.

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

They also used to have a rubber duck in it.

[wumpus]

1 hour ago, Admiral Fluffy said:

Corresponding wikipedia article:https://en.wikipedia.org/wiki/Alfa-class_submarine

A college has an on-site nuclear reactor.

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

They also used to have a rubber duck in it.

Must be pretty common, here's another: http://radiation.umd.edu/reactor/

Wouldn't be too surprised if many/most have been shut down.

[Terwin]

On 3/8/2022 at 11:15 AM, wumpus said:

Must be pretty common, here's another: http://radiation.umd.edu/reactor/

Wouldn't be too surprised if many/most have been shut down.

This page: https://en.wikipedia.org/wiki/Research_reactor#Research_centers

Lists 35 active reactors and 17 decommissioned ones

Although this page: https://en.wikipedia.org/wiki/List_of_nuclear_research_reactors

seems to list a lot more reactors than the 52 on the other page(including decommissioned Manhattan project reactors), so I guess it just depends on how you define a research reactor.

[DDE]

 

[kerbiloid]

Gabon is the first country in history, having their own nuclear reactor.

Long before US, SU, and others.

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

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

The motherland of nuclear physics.

[SunlitZelkova]

Fun fact: Long before the hype over Poseidon/Status-6, the Soviet Union considered building big torpedoes for attacking coastal cities with nuclear weapons. The Project 627 class (NATO reporting name: November) would have carried a 1500mm torpedo (roughly 3x the size of a standard torpedo) with a 3.54 ton warhead. Despite the strategic mission being dropped, this design went on to become the USSR's first nuclear powered submarine.

[DDE]

25 minutes ago, SunlitZelkova said:

Fun fact: Long before the hype over Poseidon/Status-6, the Soviet Union considered building big torpedoes for attacking coastal cities with nuclear weapons. The Project 627 class (NATO reporting name: November) would have carried a 1500mm torpedo (roughly 3x the size of a standard torpedo) with a 3.54 ton warhead. Despite the strategic mission being dropped, this design went on to become the USSR's first nuclear powered submarine.

That was one of the proposed applications of the Tsar-Bomb. Hence some people jumping to the conclusion that Poseidon carries one.

Also, the project may be as old as 1988. The GRAU index "2M39" was encountered in documentation from June 1992, and said documentation already included procurement of radiation shielding (2Ф39.1 КБ3.01) for a depot in Vilyuchinsk. All of this fancy kit probably dates back to the early-to-mid-1980s, which saw a barrage of incremental responses to SDI getting various levels of funding.

[SunlitZelkova]

Fun fact: As part of the MX missile program (later named Peacekeeper), a number of basing options were considered, including, but not limited to-

1. Building 4,600 hardened shelters over 14,200 square kilometers (probably around Utah) and having 4,400 decoy TELs and 200 actual TELs swapping between them via a purpose built road. This would have cost 37 billion dollars in 1979 and actually got approved by President Carter, only to be canceled by Reagan. I do wonder how the Soviets would have responded to this though...

2. Building missile siloes in hard rock (like granite).

3. Building small submarines for ICBMs, which would basically duplicate the Trident SLBM program.

4. Basing the ICBMs on ships disguised as merchants. IIRC the Soviets considered doing the same thing with the R-39 of the Pr. 941 class SSBNs (NATO reporting name: Typhoon).

3. Rail basing, in which launcher cars painted like reefer cars would carry missiles. They would remain on base and deploy to the main rail network in times of crisis. This was the mode that actually got approved and was only canceled when the Cold War ended.

4. Building 900 meter deep launch shafts in a mountain and a cavernous base connecting them below. TELs are based there, and then drive up to a shaft to launch their missiles. Either 10 separate bases with 20 missiles each would be built, or a single base with 100 shafts and all 200 missiles.

6. Putting two missiles on a derivative of a wide body airliner. The planes takeoff when an attack is detected and then launch their missiles in flight.

5. A seaplane carrying four missiles. It would sit at a random location in the ocean when on alert/patrol and take off to launch its missiles. It would have had a take off weight of 907 tons and a 114 meter wingspan.

6. Uncrewed, 117 ton hovercraft with a single missile on it. 600 of these would patrol over 233,000 square kilometers.

7. Building 4,600 pools and swapping 200 real canisters with missiles and 4,400 decoy canisters around between them. Each pool would be roughly 90 meters long, 30 meters wide, and 12 meters deep, and hold roughly 29,500,000 liters of water (ten Olympic swimming pools). Each pool would be spaced one mile apart, and roughly 8,000 kilometers of new roads would be required. The canisters could erect themselves and fire without crew assistance.

8. 200 uncrewed canisters released into the ocean. They would drift, and then on command would right themselves and fire their missiles.

9. 200 uncrewed canisters tethered to the ocean floor. They would pop up to the surface and then launch their missiles on command.

Source is this blog, which is sourced from the original basing study document, the link to which no longer works- https://baloogancampaign.com/2017/01/09/icbm-basing-modes-can-hide-icbms-today/

I did find this, however the full original study does not appear to be anywhere anymore- https://ota.fas.org/reports/8116.pdf

[DDE]

There was also at least one version involving a truck-based TEL moving either in a trench with overhead camouflage, or a shallow tunnel with spread-out firing position. An area the size of a national park would have to be riddled with such tunnels.

2 minutes ago, SunlitZelkova said:

9. 200 uncrewed canisters tethered to the ocean floor. They would pop up to the surface and then launch their missiles on command.

This was seemingly matched by the Soviet/Russian Skif project, although by now there's controversy whether it existed or was just misperception or disinfo around the Poseideon torpedo.

Continuing from there, I believe the Soviets had ideas about hiding SSBs in Lake Baikal and even the Kaspian, and the US considered the Great Lakes.

[JoeSchmuckatelli]

These are examples of people coming up with potential problems... then solving those problems.

...

We are, if nothing else, a creative species.

[kerbiloid]

7 hours ago, SunlitZelkova said:

the link to which no longer works- https://baloogancampaign.com/2017/01/09/icbm-basing-modes-can-hide-icbms-today/

http://web.archive.org/web/20210307020909/https://baloogancampaign.com/2017/01/09/icbm-basing-modes-can-hide-icbms-today/

[StrandedonEarth]

 

[DDE]

10 hours ago, StrandedonEarth said:

 

I think there was a recent movie about the dangers of provoking the Moon...

[kerbiloid]

Spoiler

 

 

[Minmus Taster]

On 2/24/2022 at 12:52 PM, Admiral Fluffy said:

Kaboom?

 

Yes Admiral, kaboom.