Wikipedia:Reference desk/Archives/Science/2021 June 14

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June 14

Tidal forces from a black hole

If a white dwarf or a neutron star were orbiting a black hole, could they be ripped apart by the tidal forces from the black hole’s gravity? I’m wondering how much the white dwarfs’s(and neutron star’s) own strong gravity would protect it. Rich (talk) 18:21, 14 June 2021 (UTC)

See tidal disruption event for the more general phenomenon (where the disrupted star is usually not a white dwarf or a neutron star). There's a review volume [1] with articles on various aspects of this topic, where one of the articles [2] covers disruptions of a white dwarf. You can also find a preprint of this article on arxiv: [3]. As you say, the white dwarf's own gravity is quite important. Eq. 2 in the chapter gives a simple formula for the tidal radius, that is, how close the white dwarf must get to the black hole before tidal disruption begins. Although this type of event should be possible, it does not seem that they have been observed so far. There are also some articles on tidal disruption of neutron stars, where the idea seems to be that the tidal disruption can change the gravitational wave signature of the NS-BH merger: [4], [5]. --Amble (talk) 20:04, 14 June 2021 (UTC)

So far, there are no definite detections of a NS-BH merger at List of gravitational wave observations. But there has been an observation of what might be a gravitational wave event that might be associated with something that might be a gamma-ray burst that all might have come from a NS-BH merger that might have involved tidal disruption of the neutron star: [6]. --Amble (talk) 20:21, 14 June 2021 (UTC)

It has also been suggested that a neutron star's own gravity might participate in the merger by eating it from the inside rather than protecting it: [7] --Amble (talk) 20:23, 14 June 2021 (UTC)

(I was fascinated to learn about the candidate event and the precursory collapse idea, so thanks for leading me to those!) --Amble (talk) 20:27, 14 June 2021 (UTC)

Good info, thank you. Rich (talk) 12:19, 16 June 2021 (UTC)

What happens if you drink liquid methane?

This is a question my child asked me. I know it's ridiculous, but I told him I'd ask! So, what would happen if you drank liquid methane?173.54.208.122 (talk) 19:01, 14 June 2021 (UTC)

How old is this child and what context led them to this question? As methane has a boiling point of -182 °C, your mouth, esophagus, and stomach tissue would very quickly freeze, and I imagine things go downhill from there. 0 out of 10, would not recommend. --OuroborosCobra (talk) 19:33, 14 June 2021 (UTC)

From [8]: "Skin contact with liquefied Methane can cause frostbite"

Also read: Methane#Safety--Bumptump (talk) 19:37, 14 June 2021 (UTC)

I think the blood in the arteries may start to freeze as the liquid goes down the esophagus. The ascending aorta and the common carotids run close.^[9] Although they are separated by the trachea, −182 °C (−296 °F) is really really cold. Ice crystals in the blood may cause an embolism cutting off the blood supply to the brain. Another risk, which I think is real, is that the methane will boil fervidly, causing the stomach to explode. I recommend not to try this at home or elsewhere.  --Lambiam 21:57, 14 June 2021 (UTC)

• Liquid nitrogen has a very similar boiling point. I suggest you check our article on liquid nitrogen cocktail. I quote:

  On 4 October, an 18-year-old woman (...) was admitted to hospital with severe abdominal pain and shortness of breath after drinking a cocktail prepared with liquid nitrogen while celebrating her birthday at a bar in Lancaster city centre.[6] A medical team diagnosed her condition as perforated stomach, and performed a gastrectomy to save her life.[6].

  . Your effect will be similar enough, provided the evaporating methane doesn't ignite before you get to that point. Fgf10 (talk) 22:56, 14 June 2021 (UTC)

• DO NOT TRY THIS AT HOME. I had a chemistry professor in college who was a bit crazy, and he used to demonstrate the leidenfrost effect by gargling liquid nitrogen. It is possible to do so without injuring yourself (he'd done it hundreds of times), but if you're not careful you can hurt yourself. Here is is, some decades after I first had him, doing this exact lecture. You can see him demonstrate and explain how it works near the beginning of the video, starting at about 2:50. --Jayron32 11:53, 15 June 2021 (UTC)

So no sparklers in your liquid methane cocktail then :-) Alansplodge (talk) 10:33, 15 June 2021 (UTC)

The short answer, which your kid should understand, is, "You'll die." And given all the above, in effect you could die by fire and ice at the same time. ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:02, 15 June 2021 (UTC)