Subject: Can someone please explain?
Posted by: Mixamatosis
Date: Jan 21 17
I've read that it's dangerous to mix ammonia and bleach. Variously I've read that it can produce deadly cyanide gas, chlorine gas (which is said to be bad for you) and even explosions.
However swimming pools are kept fit for use with chlorine, and our urine contains ammonia but then we may clean toilets with bleach. Also many cleaning products contain either ammonia or bleach and it would be easy to use them unthinkingly in combination.
How is it that people aren't generally harmed by these dangers when swimming in swimming pools or doing daily cleaning, or are we being harmed at low level and is the harm cumulative?
Posted by: Mixamatosis
Date: Jan 21 17
I've read that it's dangerous to mix ammonia and bleach. Variously I've read that it can produce deadly cyanide gas, chlorine gas (which is said to be bad for you) and even explosions.
However swimming pools are kept fit for use with chlorine, and our urine contains ammonia but then we may clean toilets with bleach. Also many cleaning products contain either ammonia or bleach and it would be easy to use them unthinkingly in combination.
How is it that people aren't generally harmed by these dangers when swimming in swimming pools or doing daily cleaning, or are we being harmed at low level and is the harm cumulative?
526 replies. On page 21 of 27 pages. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
brm50diboll 
|
Of course it doesn't contradict what Brian Cox said. My point is what Brian Cox said is hardly new. We've known about the principle of stellar nucleosynthesis for several decades now. And I've discussed it myself in this thread. By the way, I was a bit imprecise in my language. Most of the helium in the universe today *was* produced by nuclear fusion inside stars. But *some* helium predates the existence of stars, and formed a few hundred thousand years after the Big Bang, when temperatures had dropped enough for atomic nuclei to become stable. As for Betelgeuse, most of what we know about celestial bodies comes from the science of spectroscopy. Betelegeuse is actually one of the few stars big enough and close enough for us to get a reasonable image of its surface. But while spectroscopy of Betelgeuse reveals it is in a late stage of stellar evolution (or stellar death, if you prefer), it is *not* in the latest stage that has been observed in other stars. Astrophysicists have inferred from Betelgeuse's spectra (quite indirectly) that in the deepest part of Betelgeuse's onion-shaped core, there is nucleosynthesis of silicon and sulfur occurring. Wake me up when they tell me it's calcium and titanium. The last stage is nucleosynthesis of iron, but that only lasts about one day before the supernova, so it is unlikely to be detected. As I've mentioned before, a more likely candidate for a spectacular Milky Way supernova is Eta Carinae, which spectroscopy reveals is in a later stage of stellar evolution than Betelgeuse. But Eta Carinae is about six times farther away than Betelgeuse, is deeply imbedded in a dense nebula of its own shed gases, has companion stars complicating the matter, and, most importantly, is a far southern star that can never be seen by most of the population of the Northern Hemisphere because it never rises above the southern horizon in their locations. Nevertheless, Eta Carinae is a better candidate for next big Milky Way supernova than Betelegeuse. Reply #401. Apr 08 19, 11:41 AM |
Mixamatosis
|
He did say that Betelgeuse was the nearest candidate for supernova. Anyway, none of this may be new but it was described and communicated in such as way as to make it very interesting (for me and I suspect many others who wouldn't normally watch astronomy programmes because it's easy to get lost in all the science at times, if you are not a scientist). Reply #402. Apr 09 19, 3:00 AM |
| brm50diboll
|
I don't mind popularization of science programs. They are very interesting. We need them. And Betelgeuse is the nearest star to us that will eventually go supernova. Red supergiants are quite rare, actually. Far less than 1% of stars, but very prominent. Their rareness is due in part to their short lifespans, less than 10 million years. For a human, that sounds immensely long. But for stars, it is extremely short. The bigger the star, the shorter it lives. Saying Betelgeuse will go supernova sometime in the next 100,000 years sounds very long for a human, but it is practically an instant in the time span of stars. The smallest true stars, the red dwarfs, have lifespans in the trillions of years. When one considers the universe itself is less than 14 billion years old, all the red dwarfs out there (and they actually are the most common type of star, though they are too dim to be seen in our night skies) are all still babies. Reply #403. Apr 09 19, 6:15 AM |
| Mixamatosis
|
One thing I liked was his description of how big a star gets when it's in its dying (red) phase. If I recall correctly he said our entire solar system would fit inside the radius of Betelgeuse. Reply #404. Apr 10 19, 1:41 AM |
| brm50diboll
|
Well, up to Jupiter's orbit. Dying stars like Betelgeuse are inherently unstable and therefore variable. Betelegeuse fluctuates in size, temperature, and brightness. John Flamsteed devised a naming system for stars that often did not already have common names, although his system included stars that did have pre-existing common names. He named stars by the constellation they belonged to (with Latin endings) and Greek letters which usually, but not always, reflected the relative brightness of the star in its constellation. For example, Sirius (the brightest night star of all) is obviously the brightest star in its constellation of Canis Major and therefore received the Flamsteed designation as Alpha Canis Majori. Antares (another red supergiant) is Alpha Scorpii. But it is curious that Betelegeuse is *not* the brightest star in Orion. Rigel (a blue supergiant) is. Yet Betelegeuse is designated Alpha Orioni, while Rigel is designated Beta Orioni. Why? Betelgeuse, as a variable star, is usually slightly dimmer than Rigel. Its average brightness is less than the average brightness of Rigel. But, due to its variability, sometimes it briefly exceeds Rigel in brightness. Perhaps when Flamsteed was assigning his designations, Betelegeuse was temporarily brighter than Rigel. Higher level fusion inside old stars does not proceed smoothly. The core (where the fusion occurs) expands and contracts. When the core contracts, it gets hotter, and when it expands, it gets cooler. Paradoxically, the outer layers of the star expand and contract in exact reversal of what the core does. When the core contracts and becomes hotter, the increased heat drives the outer layers further away from the core and they cool. But the increased surface area of the star's surface causes the star to become brighter, despite the cooling surface. When the core expands and becomes cooler, the outer layers fall inward and become hotter, but the decreased surface area of the star makes it dimmer. So big, cool Betelegeuse is brighter than small, hot Betelgeuse. The fluctuation is somewhat irregular. In any event, Betelgeuse's radius still fluctuates between a minimum of slightly outside Mars' orbit (if Betelgeuse were in place of our sun) to a maximum of slightly inside Jupiter's orbit. So, no, Betelgeuse is not bigger than our solar system. But Earth would definitely be well inside Betelgeuse at all times if it were in place of our Sun. Because Betelgeuse is a cool, red star, it radiates primarily in the infrared, not visible radiation. Most of the energy that Betelgeuse emits is not of the visible type. If it were, Betelgeuse would be about ten times as bright as it is. Although Betelgeuse is the closest red supergiant to us (and not really that close, as compared to other well-known stars like Sirius, Procyon, Arcturus, Vega, etc.), it is by no means the largest red supergiant, the most luminous, or the most unstable. There are other supergiants much further out that easily defeat Betelgeuse for those titles. Reply #405. Apr 10 19, 10:42 AM |
| brm50diboll
|
Correction: I confused Flamsteed with Bayer. Johann Bayer and John Flamsteed were both 17th century astronomers, but Bayer came first and used Greek letters, while Flamsteed used numbers. So in my above post, everywhere it says Flamsteed it should say Bayer. Alpha Orioni is the Bayer designation for Betelegeuse. (Betelegeuse's Flamsteed designation is 58 Orion.) Reply #406. Apr 10 19, 11:04 AM |
| brm50diboll
|
Betelgeuse. Where did that extra e come from? Betelgeuse, Betelgeuse, Betelgeuse! Reply #407. Apr 10 19, 1:16 PM |
| brm50diboll
|
Alpha Orionis. My Latin conjugations or declensions or whatever they are properly called aren't so good. English is a lot simpler. We leave our nouns alone in that respect. And why do languages assign gender to inanimate objects? I could really get off on a rant about that. One year of college German was more than enough for me. Der, die, das... C'mon! "The" is a whole lot simpler. Reply #408. Apr 10 19, 1:26 PM |
| Mixamatosis
|
You're right and he did not say the whole of our solar system would fit inside Betelgeuse. That's my mis-remembering. Many languages have male and female nouns. The others that I know of are French, Italian and Spanish, all highly influenced by Latin. Maybe it comes from ancient times when people believed that everything was inhabited by some male or female spirit or god. I don't know why English lost or never had that. Betelgeuse is a funny name. In English we pronounce it Beetle Juice but it looks to me like a French name that would be pronounced differently in French - something like Bettel gurze (with the soft English sounding r not the pronounced American one). Reply #409. Apr 11 19, 1:08 PM |
UmberWunFayun
|
I watched a movie last night called 2:22. It was entirely fictional and scientifically inaccurate, but the storyline hinged on the idea that a star going supernova could have interesting effects on the rest of the universe, including events and timelines on Earth. Reminiscent of 'Knowing' but without the aliens, it was a good watch, and reminded me of the conversation here, which is why I'm bringing it up. I also quit German after one year. Endless tenses! The three in French I could deal with, but having all those extras and a boring teacher made it too unenjoyable for something that was elective. I tried learning Old Norse, too, and that's even worse; not only is there male, female, and plural, but the entire sentence structure changes if the plural refers to groups of differing numbers, for instance, a man and his wife walking is different than a man and his friends, several men, lots of men, or hundreds of men, and the tense also depends on how they were walking, what for and where to. And they say English is complicated! Reply #410. Apr 16 19, 8:29 AM |
| brm50diboll
|
At Texas A&M University where I majored in Chemistry, we were required to take two semesters of a "scientific and technical" foreign language. Spanish (the most common foreign language taken in Texas) was *not* an option. In fact, there were only three languages A&M deemed "scientific and technical": Russian, German, and French. I did not like Russian because they use the Cyrillic alphabet, and I didn't want to bother with learning a different alphabet. I didn't like French because it just sounds hopelessly effeminate to me. So I chose German. I made As, and it wasn't that bad, but some aspects of it were quite annoying. I've already mentioned the genders for inanimate objects. But German uses a lot of what in English would be considered run-on sentences: very long sentences that may go on for a whole page and, very irritatingly, leave the main verb to the very end. German is said to be a close relative of English. It's a close relative of Anglo-Saxon actually. After the Norman invasion, English changed so much that very little of its Germanic roots is still evident. But English is obviously not much like French, either. The French scenes in Henry V were totally opaque to me and I was only able to get through them from the footnotes. But I understand they used a very basic version of French. I know just a little Latin (nouns) from astronomical and anatomical terminology. English is the only language I'm fluent in. I generally use standard American English, but I can't resist the temptations to occasionally show off my vocabulary. I also deliberately regress into Texan from time to time. Reply #411. Apr 16 19, 12:29 PM |
| brm50diboll
|
I have not seen 2:22, but I noticed it's on Hulu which I have, so I think I'll try to squeeze it in sometime over the next week. Looks intriguing. Supernovae are phenomena possible only with the very largest of stars. The sun can never go supernova. Even Sirius is too small to ever go supernova. This causes problems in science fiction because a lot of writers just assume any old star can go supernova and I notice it when the star they claim went supernova in their story wasn't of the right type to be able to do so. Reply #412. Apr 16 19, 1:05 PM |
| brm50diboll
|
OK, Mix. I've watched 2:22 and it was an interesting story, more romance than science fiction, really. But I liked it. The details of how the supernova causes the time-distortion phenomena observed are never really explained, but that's OK. They did have the supernova occur 30 light-years away because the events were set 30 years apart, but a real supernova occurring that close to us would have devastating effects, but I'm quibbling here. Thanks for the mention, Mix. Enjoyed it. Reply #413. Apr 18 19, 1:55 PM |
| UmberWunFayun
|
It was me, not Mix, but I know you've been very busy lately so I'll forgive you ;-) Glad you enjoyed it, I watched it soon after reading this blog and the coincidence was a fun addition. Reply #414. Apr 18 19, 6:25 PM |
| UmberWunFayun
|
The effects were pretty devastating for the artist ex-boyfriend. Reply #415. Apr 18 19, 6:27 PM |
| brm50diboll
|
I apologize. Need to pay more attention to the avatars. But by devastating, I meant what is described in the article I am posting below: mass extinctions, destruction of the ozone layer, etc. https://earthsky.org/astronomy-essentials/supernove-distance There are no real stars that close to us capable of exploding as a supernova (now). Due to the fact that the sun (and its solar system, including us) revolves around the Milky Way at a different rate than other stars, the stars that are close to us now will not be in a few million years (so the constellations will be completely changed) and other stars not close to us now will be close to us in the distant future. So some day in the distant future, we *will* be close to a star that goes supernova. (Happens about once every 12 million years, roughly), which will have dramatic consequences for all life on Earth when it does. Betelgeuse is not nearly close enough. Reply #416. Apr 18 19, 8:40 PM |
| UmberWunFayun
|
Not even if you say it three times? Sorry. I was joking about the devastating thing, too, I knew what you meant. The whole conversation about supernovae has been really interesting, that was why it came to mind immediately when I watched the movie, it was lingering at the forefront of my very busy mind. Reply #417. Apr 19 19, 11:10 AM |
| UmberWunFayun
|
Busy as in cluttered and chaotic, not busy as in working hard. I might do better at quizzes if my storage system was a bit tidier. Reply #418. Apr 19 19, 11:13 AM |
| Mixamatosis
|
Interesting stuff about languages here. I think Spanish and Italian might be the easiest languages to learn for an English speaking person, especially if they know any Latin, but sadly I didn't have the chance to learn them. I was trying to learn Spanish for a holiday in March and I didn't find it difficult. The difficulty for me is my memory is not as retentive now for learning new languages. The main difficulty I came across in Spanish is that they sometimes use the same words to mean different things and you can infer the meaning from the context or from an accent on the word, but in conversational Spanish, you don't see accents and you have to be good at the language to pick up the context. I only got so far with it so there may be other difficulties lurking once you get deeper into the language. Reply #419. Apr 19 19, 1:08 PM |
| Mixamatosis
|
I didn't go on the holiday anyway. Had to cancel it as we came down with bad colds. Reply #420. Apr 19 19, 1:10 PM |
526 replies. On page 21 of 27 pages. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
Legal / Conditions of Use
|
|
: