Wikipedia:Reference desk/Archives/Science/2026 February 2

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February 2

Solar charging

My solar-powered watch often runs down in the winter. I haven't been able to determine whether it recharges more quickly on a window sill (on a gloomy day) or under an LED desk lamp. Does the source of the light make any difference? Shantavira|^{feed me} 10:31, 2 February 2026 (UTC)

I would guess it'd probably charge faster on your window sill. Even if the light on the window sill is less direct, it is more intense. Indirect sunlight is closer to 1,000 lux, while a typical LED lamp is probably closer to 100 lux. The windowsill will probably give your watch more power.

Much love, rock on!

⚠︎ ArkadenBoden ⚠︎ (talk) 14:15, 2 February 2026 (UTC)

Solar cells can absorb light of various wavelengths, including ultraviolet, visible, and infrared. Sunlight has a wide spectral range (from ultraviolet to infrared), while artificial light sources have a much narrower spectrum, making solar cells ideally suited for absorbing sunlight. Stanleykswong (talk) 16:36, 2 February 2026 (UTC)

It could depend both on the watch and the light. I have a light-powered calculator that sits under my desk lamp, and I have to turn the lamp up to at least medium or the calculator won't come on. I wonder, in your case, whether a "grow-light" would work better? ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:11, 2 February 2026 (UTC)

On a proper gloomy day around midwinter, the PV inverter in my home doesn't come alive all day, and I'm still 1500 km south of the Arctic Circle. That's less than 1% of the illuminance of a sunny day.

It depends a bit on the composition of the solar cell and the spectrum of the light. Single-junction solar cells are most efficient if most of the light is at an energy slightly above the bandgap of the semiconductor. PiusImpavidus (talk) 11:47, 4 February 2026 (UTC)

Organ damage in pre-eclampsia

Why does pre-eclampsia sometimes cause liver and kidney damage? The article mentions potential kidney damage, but I didn't see anything about the mechanism. This statement mentions the liver:

Oxidative stress may also play an important part in the pathogenesis of pre-eclampsia. The main source of reactive oxygen species (ROS) is the enzyme xanthine oxidase (XO), and this enzyme mainly occurs in the liver.

But because I don't know the terminology, I'm unsure if this oxygen situation is the cause of liver problems, or if it's a symptom of the liver already being endangered by something else.

I know that hypertension can harm the kidneys, since the pressure is generally bad for their tiny blood vessels — is this the source of kidney problems in pre-eclampsia? — but the hypertension article doesn't even mention the liver, so I'm guessing that the blood pressure aspect isn't itself a severe risk for the liver. Nyttend (talk) 11:33, 2 February 2026 (UTC)

It's not necessarily the hypertension, albeit it does make it worse. Pre-eclampsia creates a lot of waste products (mostly debris from damaged maternal organs) in the blood, which the kidneys may not be able to filter out. That's mostly the cause of the failure.

Of course, I'm no expert, so take this with a grain of salt.

Much love, rock on!

⚠︎ ArkadenBoden ⚠︎ (talk) 14:10, 2 February 2026 (UTC)

Hoping for a better plant identification before I upload to Commons

https://www.flickr.com/photos/jmabel/55072774567 - Jmabel | Talk 19:43, 2 February 2026 (UTC)

Have you tried asking on INaturalist (that's a link to the Wikipedia article)? Identifications are usually fairly fast, I think. Ceratarges-etc (talk) 20:12, 2 February 2026 (UTC)

@Ceratarges-etc: I'm not a member there. I tried signing up just now, but clicking on their sign-up link just brings my browser to its knees, does not get me to the sign-up page. - Jmabel | Talk 20:54, 2 February 2026 (UTC)

People seem to be finding a lot of giant rubarb Gunnera manicata in Seattle. Abductive (reasoning) 10:22, 4 February 2026 (UTC)

I'm no plant expert, but when I compare your photo with other people's photos of Gunnera species, it appears to be the same thing. TooManyFingers (he/him · talk) 05:35, 5 February 2026 (UTC)

Thanks, I went with Gunnera. - Jmabel | Talk 02:07, 7 February 2026 (UTC)