For Questions That Don't Merit Their Own Thread

[K^2]

If that whole thing's a mirror and it's aimed at you, you'll definitely see it. So if you're intentionally trying to make it visible, there are ways. Otherwise, see above.

[p1t1o]

What exactly is the resolution limit of the average human retina? Like minimum arc length discernible. Assuming sufficient contrast.

Edited July 28, 2020 by p1t1o

[kerbiloid]

Two dots are visible like a pair at the 1 angular minute distance.

[K^2]

I'm not sure above is average. It assumes healthy retina, center of visual field, and, crucialy, in focus. I'm not sure average eyesight is good enough without correction. With glasses, though, yeah most people will visualy resolve a minute of arc.

[magnemoe]

7 hours ago, kerbiloid said:

Two dots are visible like a pair at the 1 angular minute distance.

Remember seeing the ISS and it was not an dot, looked H shaped, might be more like an U or an barbell and my mind auto corrected. 

[kerbiloid]

5 hours ago, magnemoe said:

Remember seeing the ISS and it was not an dot, looked H shaped, might be more like an U or an barbell and my mind auto corrected. 

Either your eyes are much sharper than average and you can see the Jupiter moons without optics (there are people who can),
or once I saw an airplane with blinking lights, hanging at one place. (It was nearly dawn, so I guess I could see the smiling crew if kept looking.)

Anyway, 1 ang.min. is a standard average.

Edited July 29, 2020 by kerbiloid

[magnemoe]

3 hours ago, kerbiloid said:

Either your eyes are much sharper than average and you can see the Jupiter moons without optics (there are people who can),
or once I saw an airplane with blinking lights, hanging at one place. (It was nearly dawn, so I guess I could see the smiling crew if kept looking.)

Anyway, 1 ang.min. is a standard average.

Don't have very good eyesight, however very sure i was not just an dot, however it might be the brain auto correct that I was seeing. 

[K^2]

1 hour ago, magnemoe said:

Don't have very good eyesight, however very sure i was not just an dot, however it might be the brain auto correct that I was seeing. 

It's also pretty easy to get an H shape out a point source due to a slight imperfection in optics of the eye. It's really hard to say without testing you with a bunch of different shapes of different sizes to see which ones you can distinguish.

[Gargamel]

Conjecture:  The bacon number for any two spoken languages is no more than 2. 

Take any two random humans on the planet, the max number of interpreters to allow them to converse is two, where the interpreters would share a common known language.   There are enough polyglots on the planet that there should never been a need for a third interpreter between the other two. 

[kerbiloid]

Lemma 1. And almost nobody of them speaks Esperanto.

[magnemoe]

7 hours ago, Gargamel said:

Conjecture:  The bacon number for any two spoken languages is no more than 2. 

Take any two random humans on the planet, the max number of interpreters to allow them to converse is two, where the interpreters would share a common known language.   There are enough polyglots on the planet that there should never been a need for a third interpreter between the other two. 

Say you can find exceptions here 
https://en.wikipedia.org/wiki/North_Sentinel_Island
is the obvious one, as I understand none outside of it speak their language including natives on other islands nearby and an high chance none of the North Sentinelese talk other languages. 
Now if the other person live in an uncontacted tribe in Amazons, here its easier as unlike North Sentinelese languages are shared across tribes and they might have some in another tribe who both share their language and Portuguese but here its some chance you have to go trough another translation with an tribal language to get here. 

[mikegarrison]

[ARS]

Is it possible to get radiation poisoning with lethal dose if you eat enough bananas?

[DDE]

2 hours ago, ARS said:

Is it possible to get radiation poisoning with lethal dose if you eat enough bananas?

I think this has to be reworded into "is it possible to eat enough bananas to get a lethal dose of radiation".

One Banana Equivalent Dose is usually rounded up to 0.1 x 10^7 Sv. You need a couple of Gy to die from ARS; radiation-induced cancers are a far more difficult topic, because under the Linear No-Threshold model every photon of radiation has a fixed non-zero probability to kill you. Which is why it's a poor but highly conservative model.

You may have noticed the two different units, but without neutrons or protons involved the conversion coefficient is 1.

So, can you eat several tens of millions of bananas, especially within a few days?

Probably not.

Edited August 1, 2020 by DDE

[Gargamel]

You'd probably OD on potassium first, which is half of the sodium potassium pump that drives your heart.  Too much of one causes the heart to go wonky.  But you'd probably die from your stomach exploding before you got to this point anyways. 

[DDE]

16 minutes ago, Gargamel said:

You'd probably OD on potassium first, which is half of the sodium potassium pump that drives your heart.  Too much of one causes the heart to go wonky.

Same as trying to use iodized salt to protect against I-131.

[kerbiloid]

4 hours ago, ARS said:

Is it possible to get radiation poisoning with lethal dose if you eat enough bananas?

Yes, with mods.
https://www.nexusmods.com/fallout4/mods/26942/?tab=docs

[DDE]

While we're on the topic of rads, could someone with an academic login check this out and summarize the degree of protective qualities they've been able to achieve, as well as the colour of the material?

https://pubs.acs.org/doi/10.1021/jacs.0c05573#

[kerbiloid]

I don't have an academic login, but googling the mentioned substance gives me this:

[DDE]

34 minutes ago, kerbiloid said:

I don't have an academic login, but googling the mentioned substance gives me this:

Somehow I'm not sure that a modified melanin would protect me against gastrointestinal syndrome at 6 Gy.

[kerbiloid]

4 minutes ago, DDE said:

Somehow I'm not sure that a modified melanin would protect me against gastrointestinal syndrome at 6 Gy.

Som links say about "microbes and skin cells" and "resistance increased by 2..3 times"

So, definitely not the Black Blood from The 100 or vaccine from Strugatskiy bros.

Edited August 2, 2020 by kerbiloid

[p1t1o]

10 hours ago, DDE said:

Somehow I'm not sure that a modified melanin would protect me against gastrointestinal syndrome at 6 Gy.

Question:

How thick/thin a shell of neutronium would be required to stop 6Gy of radiation?

Edited August 2, 2020 by p1t1o

[kerbiloid]

Roughly, less than picometer if degenerated.

But wiki tells interesting things.
https://en.wikipedia.org/wiki/Neutronium

Quote

Neutron matter at standard pressure and temperature is predicted by the ideal gas law to be less dense than even hydrogen, with a density of only 0.045 kg/m³ (roughly 27 times less dense than air and half as dense as hydrogen gas). Neutron matter is predicted to remain gaseous down to absolute zero at normal pressures, as the zero-point energy of the system is too high to allow condensation. However, neutron matter should in theory form a degenerate gaseous Bose–Einstein condensate at these temperatures, composed of neutron pairs called dineutrons. At higher temperatures, neutron matter will only condense with sufficient pressure, and solidify with even greater pressure. Such pressures exist in neutron stars, where the extreme pressure causes the neutron matter to become degenerate. However, in the presence of atomic matter compressed to the state of electron degeneracy, β⁻ decay may be inhibited due to the Pauli exclusion principle, thus making free neutrons stable. Also, elevated pressures should make neutrons degenerate themselves.

Compared to ordinary elements, neutronium should be more compressible due to the absence of electrically charged protons and electrons. This makes neutronium more energetically favorable than (positive-Z) atomic nuclei and leads to their conversion to (degenerate) neutronium through electron capture, a process that is believed to occur in stellar cores in the final seconds of the lifetime of massive stars, where it is facilitated by cooling via
ν
_e emission. As a result, degenerate neutronium can have a density of 4×10¹⁷ kg/m^{3[citation needed]}, roughly 14 orders of magnitude denser than the densest known ordinary substances. It was theorized that extreme pressures of order 100 MeV/fm³ might deform the neutrons into a cubic symmetry, allowing tighter packing of neutrons,^[17] or cause a strange matter formation.

So, at normal conditions it would not protect at all.

But as it's compressible, we need neutronium monopropellant pressure-fed engines.
As anyway they want to add metallic hydrogen, why not the neutronium, too.

[K^2]

Without immense gravitational pressure, neutronium decays. Half life of free neutrons is less than 15 minutes. Without pressure exceeding electron degeneracy pressure, neutronium will not fare much better. It will make for a very bad shielding material, being radioactive itself, and as fuel, will have very short shelf life.

[kerbiloid]

Then we should use it quickly, and also can initiate fusion with it.