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 7 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 
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Supermassive black holes at the centers of galaxies can be categorized by how much energy is radiated from their accretion discs just outside their event horizons. That amount of energy is a function of how much matter is falling into the black hole, which is itself a function of how much matter is in the immediate vicinity of the supermassive black hole. At the low end are the quiescent supermassive black holes, which includes Sagittarius A*, the one at the center of our Galaxy, the Milky Way. There isn't too much matter infalling there, so while it shows up as a radio emitter, not a lot exciting is happening there at present. If enough matter (mostly gas and dust) infalls to superheat the accretion disc to the point that it becomes a powerful X-ray emitter, then the supermassive black hole is said to power an active galaxy. The nearest active galaxy to us is Centaurus A. Active galaxies are usually either fairly young galaxies or galaxies that have collided to grow larger and feed their supermassive black holes. Centaurus A is an elliptical galaxy that appears to be cannibalizing a spiral galaxy. At the extreme high end of supermassive black holes are the so-called quasars (quasi-stellar radio sources), which have galaxies whose supermassive black holes are pouring out tremendous amounts of energy, even in the visible light range, giving them the highest absolute magnitudes of any known celestial bodies. The supermassive black holes that power quasars appear to be devouring whole stars in their accretion discs. There are no quasars near us; the nearest are billions of light years away. But when we observe objects that far away, we are also looking deeply backwards in time. A quasar five billion light years away is not being seen by us as it is today, it is being seen as it was five billion years ago, before Earth even existed. It may well be that quasars are a stage of galaxy evolution that only existed in the early young universe. Perhaps the Milky Way itself was once a quasar which has now "settled down". Sagittarius A* today is quiescent, waiting. The Great Monster hasn't been fed anything big in a long, long time. Reply #121. Jul 30 17, 10:52 PM |
13LuckyLady
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I've been neglecting this thread, Brian. I am sorry. I'll catch up this week....promise! Reply #122. Jul 31 17, 7:46 AM |
| brm50diboll
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My remarks are becoming more detailed, as I am using terms previously explained to explain new ones. But if anything is unclear, I can always reexplain it. I often use different analogies when explaining a concept a second (or later) time. I'm about to get into cosmology and Hubble's Law. Reply #123. Jul 31 17, 11:15 AM |
| 13LuckyLady
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Brian, if you had been my teacher...school would not have been so dull! Keep posting...I'm almost caught up! Reply #124. Aug 01 17, 9:08 AM |
Litecruzer
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That reminds me of my Space Science class and teacher. I loved that class, one of my favorites ever, certainly never a dull moment. Our teacher was a character and encouraged questions, so my hand was up a lot. He would call us by our last name. He had been to several of the launches in Florida and enjoyed relating his experiences as well. Hats off to teachers who inspire. Reply #125. Aug 01 17, 9:54 AM |
| 13LuckyLady
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I had a teacher who would travel to England every year. Her stories would magically turn history into a three dimensional world and the class was off on another adventure. She was never dull! But we digress....back to Brian and his vault of knowledge! Reply #126. Aug 01 17, 10:39 AM |
| Litecruzer
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Those are fond memories, the experiences of which has helped fuel who we are today, right? To look at the world and the universe around us with awe and the desire to learn more. I like the title of this thread, "Can someone please explain?":) Reply #127. Aug 01 17, 10:52 AM |
| brm50diboll
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Mix originated this thread. I just sort of "took over". I am an amateur, but astronomy is a serious hobby for me. The upcoming eclipse is a big deal. Solar eclipses only occur during new moons, lunar eclipses only occur during full moons. The reason we don't have both every month is that the Moon's orbit around the Earth is not in the same plane as the Earth's orbit around the sun - it is inclined a few degrees, so the Moon is usually a few degrees off the ecliptic. Eclipses can only occur when the two planes intersect, so-called "eclipse seasons", which occur roughly twice a year. I say roughly because the seasons occur slightly earlier each year than the last because of a phenomenon called lunar precession, which follows an approximately 18 year cycle. Reply #128. Aug 01 17, 2:49 PM |
| brm50diboll
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One of the other things we can determine by analyzing spectra of celestial bodies is radial velocity; that is, speed in the direction toward or away from earth. Stationary spectra on earth have specific patterns of lines which are easily recognizable for different elements ("fingerprints"). The exact same patterns of lines in the spectra of celestial bodies identifies those elements in those celestial bodies, but the pattern of lines may not be in exactly the same position as they are here on Earth because the celestial body is moving generally towards or away from Earth. This is called the Doppler effect, which applies to light (all electromagnetic radiation, actually) as well as to sound. If the pattern of lines for a particular element (say hydrogen, the most common element in the universe) in a celestial body is shifted towards higher frequencies and shorter wavelengths as compared to the same pattern here on Earth, we say the lines are blue-shifted, which means the celestial body is moving generally towards us. How much the lines are blue-shifted can be used to calculate the radial velocity of that celestial body. We might find, as an example, that a star is moving generally towards us at a speed of 235 km/s. If the patterns of lines for the elements in the spectrum of a celestial body are shifted towards the lower frequencies and longer wavelengths as compared with the same pattern here on Earth, however, we say the spectrum is red-shifted. The Doppler effect in this case means the celestial body is moving generally away from us, and, once again, the amount of shift can be used to calculate the radial velocity. So we may analyze a red-shifted spectrum of a star and determine that star is moving generally away from us at 520 km/s. So analyzing red and blue shifts of spectra of celestial bodies allows us to determine if they are headed generally towards or away from us and how fast they are doing so, a very useful piece of information which allows us to determine the movements of all sorts of celestial bodies from binary stars rotating around each other to the spinning of accretion discs around black holes to the movements of distant galaxies. It is that last part, the movement of distant galaxies, that Edwin Hubble was interested in the early 20th century. Reply #129. Aug 04 17, 11:50 PM |
Mixamatosis
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Brm50diboll. I feel this thread would benefit from an index of the different things you have explained so that people could find them easily - periodically updated of course. No pressure though :-) Reply #130. Aug 13 17, 2:10 PM |
| brm50diboll
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90% astronomy. A few other stuff in answer to questions people asked. I did do one post that was not an answer to a question another person asked that was chemistry (my college major). I've mostly covered the astronomy of stars, and haven't said too much about our Solar System (yet, I probably will in the future). I'm perfectly capable of discussing chemistry, physics, biology, and even mathematics in as much detail as astronomy, but astronomy occupies most of what I've written on this thread (so far). Astronomy is actually a branch of physics, so a certain amount of physics has been discussed just in making my astronomy points, but I've also touched on a bit of chemistry and biology in my astronomy discussions as well. I don't know there's enough here yet to justify an index, especially as I plan to keep going and have plenty of new material to cover. Maybe in a few months. Besides my incidental contributions to game play advice which appear mostly on the Immortal and Epic threads here on the general board, I am currently "rotating" my contributions to three threads where my writings are a bit more than incidental: my science fiction virtual blog, this thread, and my new thread on blackjack strategy on the Entertainment board. If anyone comments on anything I have written, I reply as soon as I notice it and am able, but, barring that, I alternate my contributions in a certain order among those three threads, usually posting on the one not posted to for the longest time every two or three days, so typically, each thread gets a post from me every week to 10 days. I have both short-term and long-term interests for each of my three threads. For this one, I want it to be somewhat akin to Carl Sagan's Cosmos, a wide ranging discussion of the universe combining many different sciences, not just astronomy. My science fiction virtual blog is intended to get into a bit of philosophy, not just a series of book and movie reviews, and my blackjack strategy thread is a disguised (poorly, I hope), effort to explain statistics as the driving force behind game theory, debunking misconceptions from hunches and streaks and explaining the underlying statistics in a way that is applicable to many games, not just the one I picked. I love game theory. As always, I invite questions and comments and will change my default plans to accommodate them, but, even with none, I still have quite far to go planned for what I am doing. Reply #131. Aug 13 17, 10:45 PM |
| brm50diboll
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It was Hubble, actually, who discovered the existence of galaxies outside our own, the Milky Way. Because methods for measuring astronomical distances become less accurate the farther out we look (and this was even more true in Hubble's time), prior to Hubble, our Galaxy was essentially considered the whole universe. Many objects we now know to be other galaxies, most notably the Andromeda Galaxy (M31), were considered to be structures within our own Galaxy. M31 was known as the Andromeda "Nebula", a cloud of gas and dust within our Galaxy. But studies of variable stars, particularly a type known as Cepheid variables, demonstrated a difference between visual magnitudes and expected absolute magnitudes that could not be explained if the Cepheid variables in M31, for example, were within our own Galaxy; they had to be much, much farther away. And so Hubble showed that many of these "nebulae" were actually distant galaxies, "island universes" of their own, which, in one fell swoop, vastly expanded our idea of how large the Universe was from a few hundred thousand light years to several billion. Galaxies are held together in even larger structures, galaxy clusters, by their common gravitational attraction. We know today that the Milky Way is the second-largest galaxy in a group of galaxies known as "The Local Group". Andromeda is actually the largest galaxy among the 30 or so members of "The Local Group", most of which are small, dim, dwarf galaxies. When analyzing the spectra of Local Group galaxies, we see many of them, including Andromeda, have blue-shifted spectra, meaning they are generally moving towards us. But what do we see when we analyze spectra from more distant galaxies, those not in the Local Group? Red shifts. Lots and lots of red shifts - and in a pattern. What did all these red shifts mean? Hubble figured it out, and it is the foundation of modern cosmology. Reply #132. Aug 13 17, 11:08 PM |
| Mixamatosis
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Thought you might be interested in this. There's a bit of a "chicken and egg" debate to it, but I think the food source must have come first. http://www.bbc.co.uk/news/science-environment-40948972 Reply #133. Aug 17 17, 10:33 AM |
daver852
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Do black holes rotate? If so, if two black holes of equal mass collided but opposite spin collided, what would happen? Reply #134. Aug 17 17, 11:07 AM |
| brm50diboll
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Just now reading the last two posts. To Mix's article: Algae are interesting. I believe they may be useful for efficiently producing alternative fuels cheaply eventually. I am skeptical that algae are the reason complex animal life evolved when they did as they did. In my opinion, the Cambrian "explosion" was the result of world atmospheric oxygen percentage finally reaching a threshold level of about 10% (currently 21%, but has been as high as 30% in geologic history) which allowed for differentiation into tissues and organs after the end of a "Snowball Earth" event in the late Precambrian (or Proterozoic). Prior to that, oxygen levels were too low to support complex animal phyla. As to daver's question: Yes, black holes do rotate, and, from General Relativity, their rotation "drags" spacetime with it, so that the event horizon (where the escape velocity equals c) is no longer a sphere around the singularity, but more of an oblate spheroid, as I understand it. But I will readily confess my understanding of General Relativity is quite limited. So, two your second question as to what would happen if two black holes of opposite rotation collided, I will admit I don't have confidence in my answer, but this is my reasoning: black holes possess angular momentum (which is a vector, not a scalar property). If two black holes collided which had angular momenta of equal magnitude but in opposite direction (the direction of the counterclockwise axis of rotation - North Pole for Earth, for example), then the result would be a larger black hole with 0 angular momentum and no spin. Exactly 0 spin is almost unheard of anywhere in our universe since even slight variations would result in the two vectors not perfectly cancelling each other out. Therefore I consider the question hypothetical and very unlikely to happen. Virtually all real black holes (like virtually all celestial bodies in general) possess at least some rotation and therefore at least some net rotational angular momentum. The exact details of how net rotational angular momentum manifests itself in black holes with respect to General Relativity is out of my league, however, beyond my previous generalization of "dragging" spacetime which I read somewhere. I still believe the Law of Conservation of Angular Momentum applies universally, even in the extreme case of black holes, but I certainly can't do the math of General Relativity to back up that assertion. Reply #135. Aug 17 17, 2:23 PM |
| brm50diboll
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I don't know why autocorrect changed my "to your second question" to the obviously incorrect "two your second question". Machines are incapable of critical thinking and therefore should not be relied upon too much, especially autocorrect, which only causes me problems. I absolutely hate, HATE, the incorrect use of homophones. To, two, and too should be used correctly, as should there, their, and they're, and your and you're, among many others. But I can't seem to disable my autocorrect on my cellphone. Nothing but trouble! Reply #136. Aug 17 17, 2:30 PM |
| Mixamatosis
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I never use auto-correct, as you can probably tell. I do make the occasional typo that I don't spot but I prefer that to a programme that changes what I've written. I wouldn't know how to turn it on anyway. I fear one day I'll hit the wrong combination of keys and turn it on by accident without knowing how to turn it off. Reply #137. Aug 17 17, 4:27 PM |
| brm50diboll
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I didn't turn it on or choose to use it. It is an automatic feature of my cellphone I can't seem to turn off. Had I had a choice, I never would have used the thing. I'm actually quite good at both spelling and grammar, and would prefer to be left alone to make my own choices. When I do deviate from established orthodoxy, there's usually a tactical reason for it, often an attempt at humor. There's nothing funny or enlightening about incorrect use of homophones, however. Writing such things as "your st*pid" only proves to readers you're st*pid. Now *that* was an attempt at humor, albeit a very weak one. But now I constantly have to "police" what I write because my renegade autocorrect randomly (it seems) changes what I type and I have to manually change it back. If my post is long (and any readers of my posts know they frequently are), I have problems because I can't see my entire post before I hit submit. Sometimes it changes what I type to something that bears absolutely no resemblance to what I typed. Useless. Reply #138. Aug 17 17, 7:36 PM |
| Mixamatosis
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Is there nothing under "settings" that might allow you to turn it off? (If it's not a silly question.I expect you've tried that). Reply #139. Aug 18 17, 3:06 AM |
| brm50diboll
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Can't find anything there. There probably is a way, but I'm a bit of a technological klutz. All those Expert wins I have in computers and technology are the result of seeing the questions over and over in practice in Topic Mashes and so forth. In reality, as far as science goes, computers and technology are my biggest weakness. I would never be so arrogant as to claim anything more than bare-bones competence in those areas, certainly not any expertise. Reply #140. Aug 18 17, 9:08 AM |
526 replies. On page 7 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
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