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 4 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
13LuckyLady 
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"You're probably not going to like my answer on that." :( (chuckle)....Brian, I liked your answer. :P Reply #61. Apr 15 17, 10:22 AM |
brm50diboll
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Thanks. Reply #62. Apr 15 17, 10:34 AM |
Mixamatosis
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The female menstrual cycle averages 28 days in the Western (developed) world. In more rural societies it's more like 32 days. Reply #63. Apr 16 17, 10:17 AM |
| brm50diboll
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Yes. My point is, it's not related to the lunar cycle. But this gives me the opportunity to complicate matters by pointing out there are actually two different commonly used lunar cycles: the synodic and the sidereal lunar cycles. The one that is most commonly used is the synodic cycle, which is the average time interval between two full moons, which is about 29.5 days. Technically speaking, a full moon (like an equinox) is actually a specific *instant* in time, not a whole day, although many people don't realize that. So (and I'm making this up), it is correct to say that a full moon occurred at exactly 10:43:26 am CDT on May 3 of some year. Most people would say simply the full moon is on May 3, but if you went out at a time other than the *exact* time, what you'll be seeing is the 99.36% full moon (or something like that). 29.5 is a rounded average. Wikipedia will give a more precise number, but I usually just use numbers I can remember off the top of my head. It is an *average*, because, since the moon's orbit is elliptical and varies in speed, some lunar cycles turn out to be a little shorter or longer than others. Then there is the less commonly used sidereal lunar cycle, which is still important to nerds like me. A sidereal lunar cycle is the time it takes for the moon to make one complete trip around the celestial globe from say, a spot in Pisces (like the 0° declination, 0 hour right ascension common reference point) back to that same spot in the sky as measured against the background stars. This is different from the synodic cycle because the earth is orbiting the sun, so each full moon occurs in a different spot of the sky than the previous one. The sidereal lunar cycle averages about 27.3 days (about 2.2 days shorter than the synodic cycle, since the earth moves around the sun.) The same caveats about rounding and averages that I mentioned for the synodic cycle apply to the sidereal cycle. Neither cycle has anything to do with the human female menstrual cycle, but it is a common enough misconception that I felt I needed to spend some time to debunk it. By the way, debunking common false beliefs about astronomy is a favorite activity on one of my favorite websites: badastronomy.com . Any astronomy nerds out there should check it out. It especially goes after astrology. Reply #64. Apr 16 17, 1:13 PM |
| brm50diboll
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So declination is like latitude. Stars north of the celestial equator have positive declinations, stars south of the celestial equator have negative declinations. Polaris, the North Star, has a declination of *almost* +90°. (Actually, about +89.25°). So it *almost* stays in a fixed position directly above the Earth's North Pole. From other places in the Northern Hemisphere, the altitude of Polaris can be used to calculate the latitude. So if Polaris is 33° above the northern horizon, then the latitude of that position is about 33°N. Polaris is not visible in the Southern Hemisphere. Stars with very positive declinations appear to move in a circle around Polaris. Stars with very negative declinations (visible in the Southern Hemisphere) appear to move in a circle around a spot in the constellation Octans. The closest thing to a "South Pole Star" is Sigma Octantis, but it is very dim and not easily seen, so does not make a good marker like Polaris does in the North. Stars with declinations that match the observers' latitudes have the unusual property of being able to pass through the observers' zenith. So if you are observing from latitude 33°N, various stars will pass directly overhead (the zenith) during the night and all the stars that do that will have declinations of +33°. I keep picking on 33° because that is the approximate latitude of Longview, TX. It turns out Vega, the fifth brightest star, has a declination near +33°. So as viewed from Longview, Vega appears to pass close to the zenith (almost directly overhead) during its season of visibility (centered on the Northern Hemisphere summer.) From Longview, at some time during the night in the summer (the exact time changes by about four minutes each day), Vega will appear to pass almost directly overhead. Vega also passes directly overhead in the winter, but it can't be seen then, because it is doing so during daylight in the winter. The seasonal aspect of most stars is a function of the other important celestial coordinate, right ascension, a subject for discussion another day. Reply #65. Apr 22 17, 5:43 PM |
| Mixamatosis
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I saw a really fascinating programme on the Sun the other night. I was most interested to learn of the 11 year cycle of sun spots and what causes them and their effects on the Earth. We had a "mini ice-age in the 18th century which coincided with a lack of Sun spots. I was reassured that the Sun has 5 billion more years of fuel to burn. After that, as it dies, it expands into a red giant which will burn the planets that are nearest to it. Reply #66. Apr 24 17, 11:59 AM |
| brm50diboll
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Yes. I do find solar science interesting. The sun's magnetic field is much more complex than earth's (or any other planet) because it is generated by plasma. Sunspots are cooler than the rest of the photosphere ("surface" of the sun) because they represent areas where magnetic field lines are concentrated and intersect the photosphere. At these points, convection of plasma is slowed, leading to local cooling, producing areas less luminous (darker) than the surrounding photosphere, hence sunspots. The exact cause of the *approximately* 11-year cycle and why it occasionally fails, as in the "Maunder Minimum" which correlated with the "Little Ice Age" in Europe, is not fully understood. In addition to sunspots, the sun's magnetic field is responsible for the phenomena of prominences, solar flares, and coronal mass ejections. The sun is not large enough to go supernova. It (as you said), is fated in about 5 billion years, to first expand into a red giant by fusing helium into carbon as its hydrogen stores approach exhaustion, then shed its outer layers as a planetary nebula when helium fusion also exhausts and the sun is not massive enough to initiate carbon fusion, then the remnant core will slowly cool over billions of years as an extremely dense earth-sized star called a white dwarf. During its red giant phase, the sun will swallow up Mercury and Venus, and possibly Earth, although this is a point of contention among astrophysicists, as mass loss by the sun as it expands will cause the orbits of the inner planets to shift somewhat outward from their present positions. Even if Earth remains outside the future red giant sun, it will be fried and life as we understand it will not be able to exist on the surface. Actually, long before the sun becomes a red giant, astrophysicists believe the sun, while it it still firmly in the main sequence of hydrogen fusion, will have increased its luminosity enough to produce temperatures sufficient to boil off our oceans. This increased luminosity effect is unrelated to "global warming" due to carbon dioxide increase in our atmosphere and would occur even if the carbon dioxide level in our atmosphere remained at preindustrial levels. Already, our middle-aged sun is about 10% more luminous than it was when it was "born" 4.5 billion years ago and the slow increase in luminosity will continue as it ages through the main sequence. Current estimates are the luminosity rise alone will make Earth unlivable in about one billion years, long before the sun becomes a red giant. Reply #67. Apr 24 17, 5:27 PM |
| Mixamatosis
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I understand that solar flares occur where energy bursts through the magnetic field intersections over the hotspots and these cause the aurora borealis on Earth (or the Northern lights and Southern lights). I suppose when the hot spots stop emitting energy towards Earth, that could be the explanation of the mini-ice age. At least that seemed to be the implication in the programme though it wasn't clearly spelled out. There's no doubt that man's activity is contributing to global warming though. The oceans absorb excess carbon dioxide up to a point but when temperatures rise they can't absorb as much causing temperatures to rise more causing them to absorb less and so on in a viscious circle. Reply #68. Apr 25 17, 11:51 AM |
| brm50diboll
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My point was not to deny climate change. It was to say the luminosity effect will make Earth unlivable long before the sun becomes a red giant, although a billion years from now is still a very long time. As to carbon dioxide, that mechanism of climate change works much, much faster. Within a hundred years, we should see a rise in sea levels. But I'm not going to get into the politics of it. There is a whole science called paleoclimatology which reconstructs Earth's climate from fossil data from past geologic eras. With a very high degree of precision, we know what carbon dioxide levels, oxygen levels, average world temperatures, and sea levels were for the past 500 million years or so. The Earth has been both far warmer and far cooler in past eras than it is now. In the Cretaceous period, to pick one example, average world temperatures were about 5°C higher than today and sea levels around 80 meters higher than now. North America was bisected by a vast shallow inland Sea connecting what today is the Gulf of Mexico to what today is Hudson Bay, with the whole Mississippi Valley area submerged in the inland sea. Even the poles were ice free. This was a time of the peak of the age of Dinosaurs. It was a time of tremendous biodiversity, far exceeding that of today. Increased global temperatures definitely changes landforms. It does not create mass extinctions per se. If sea levels start rising, I predict people will move. The history of humanity has been, and will continue to be, a history of mass migration. Or we can build dikes and levees and live below sea level. The Dutch have already done that for hundreds of years. I don't know that being able to grow mangoes in Greenland is necessarily a bad thing. It will vastly increase the agricultural productivity of Canada and Siberia, for one thing. Maybe the future megalopolises of the world will not be Shanghai, Tokyo, Mexico City, and New York City. Maybe they will be Anchorage, Murmansk, Stockholm, and Vladivostok. But I live in Texas. It'll be 130°F here. No problem for us Texans. Just a little hot spell. Reply #69. Apr 25 17, 2:23 PM |
| Mixamatosis
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I can't get worried about a billion years in the future but there is plenty to worry about now. It may have been 5 degrees hotter in the cretaceous period but humans did not live then. It may sound nice to have more heat but I don't thrive in hot climates. Already this year there's been no significant rain here in April which is the growing season and usually a rainy month. The hotter it gets the more dangerous creatures, such as those in Australia, will find a home in the UK and our lush green lawns will go. Even in Paris, which is close, you don't find the lush green lawns we have in London now. Much more of the world will be unable to grow food to feed itself and wild more wild animals will die and more species become extinct. This may not yet be disastrous for man but we are ruining the world like a bad housekeeper, not only neglecting their responsibilities but actively damaging things. Perhaps the story of Eden is a parable of the future. We have Eden now and we're going to ruin it. Reply #70. Apr 26 17, 1:24 AM |
| brm50diboll
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Blaming every bad weather event on climate change is a fallacy. The Cretaceous matters because it exposes several fallacies about the natural regulatory mechanisms for climate. First, incorporation of carbon dioxide into the oceans is not the primary way the atmosphere lowers carbon dioxide. That process actually is done by corals (a type of animal, actually), which takes carbon dioxide and uses it to create calcium carbonate, which ends up as limestone or marble rock, eventually. But that is a minor mechanism for lowering carbon dioxide. By far the most important mechanism is photosynthesis by plants, algae, and cyanobacteria. Carbon dioxide is fuel for them, both on land and in the sea and photosynthesis fixes carbon into sugars and creates oxygen. This mechanism has been going on for over 2.5 billion years and has corrected even the worst periods of global heating (many far worse than the Cretaceous). A few actual facts are in order: Preindustrial carbon dioxide levels in Earth's atmosphere were 280 ppm (parts per million), or 0.028% of Earth's atmosphere. Current carbon dioxide levels are 400 ppm (0.040%). Carbon dioxide levels during the Cretaceous were 1700 ppm (0.17%), which was over four times our present "inflated" levels (and no humans were around to cause it). Carbon dioxide levels on Venus, by contrast, are a whopping 900,000 ppm (90%), which still vastly understates the amount of carbon dioxide in Venus's atmosphere, since Venus's atmosphere is 90 times as dense as ours. Earth has *never* and furthermore will *never* come close to having as much carbon dioxide in its atmosphere as Venus. Photosynthesis is self-regulatory. That is, when carbon dioxide levels are high (by Earth standards), photosynthesis rates increase. Of course they do: carbon dioxide is fuel for photosynthesis; it's like adding gasoline to a fire. Furthermore, the increase in the rate of photosynthesis with increased carbon dioxide levels is geometric, not arithmetic. So doubling carbon dioxide levels (which human activities haven't done yet as 400 is less than twice 280) more than doubles the world photosynthesis rates. What about deforestation? Important for habitat destruction for macrofauna people care about, but grasses and crops actually are more efficient at photosynthesis than trees, and that ignores the even greater contribution of algae, which existed long before plants even evolved a little over 400 million years ago. The obvious sign that world photosynthesis rates go up when carbon dioxide levels go up is oxygen. Oxygen would not even exist on Earth if it weren't for photosynthesis. During the Cretaceous, oxygen levels were 30%, well above our present 21% oxygen levels, because photosynthesis levels were so much higher than they are today, and further, despite the fact there were more animals back then to turn the oxygen back into carbon dioxide. In terms of world biomass, produces always have and always will vastly outnumber consumers in our ecosystems, which is why oxygen levels vastly exceed carbon dioxide levels in our atmosphere. Photosynthesis is a much more efficient process for removing carbon dioxide than cellular respiration is for increasing it. Of course, there's practically no oxygen in Venus's atmosphere, but that is to be expected, as there is no life there, and most life is producers (photosynthesizers), which keep carbon dioxide levels low even in the worst heating episodes in Earth's very long geologic history. We couldn't raise Earth's carbon dioxide levels above 3000 ppm even if we humans deliberately tried to (and we're not). So the idea that there will be a runaway greenhouse effect that will turn Earth into Venus with carbon dioxide levels well under 1% is complete poppycock. Already, even with our modest increase in carbon dioxide levels over where it was 200 years ago, documentation of increased photosynthesis rates worldwide is evident. And climate scientists are predicting a 5-10 meter increase in world sea levels, not even close to the 80 meters in the Cretaceous, which again, was not caused by human activity. So next time there is a drought or a heat wave, it's a drought or a heat wave. It's not Earth turning into Venus. Sea level rise is important, particularly to the Maldives and Kiribati, but it's not the end of the world. Reply #71. Apr 26 17, 5:24 AM |
| brm50diboll
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By the way, the Chinese, who contribute more to carbon dioxide than the West, have a vested interest in seeing to it sea levels don't rise too much: their recently built air and naval bases in the Spratly islands of the South China Sea are built on mud flat islands with elevations less than one meter above sea level. If sea levels rise a couple of meters (a big if, as far as I'm concerned, maybe in 50 years), then those bases will be sunk. Reply #72. Apr 26 17, 5:34 AM |
| brm50diboll
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Now to right ascension, which is similar to longitude. But right ascension is not measured in degrees, it is measured in units of time like hours, minutes, and seconds. There are 24 hours of right ascension in the celestial globe, each hour corresponds to 15°. The reason RA (I will use this abbreviation now) is measured in units of time is to aid astronomers in calculating times for celestial events. Just as there is a Prime Meridian of longitude, the RA equivalent would be the zero hour RA meridian. The zero hour RA meridian passes through the point in the sky where the Sun is at the instant of the Northern Hemisphere's vernal (spring) equinox, which is when the Sun crosses the celestial equator (0° declination) heading north, which typically occurs each year around March 20 or 21. (It varies a little because there are not exactly 365 days in a year.) Now the vernal equinox is a time, but in astronomy it can also be used to refer to a point in the sky (0° declination, 0 hours RA). Traditionally, this special point in the sky has been called "The First Point of Aries", because in ancient times, it was in the constellation Aries. Even today, in astrology, it marks the beginning of the sign of Aries. But due to the phenomenon of the precession of the equinoxes, it is no longer found in Aries in astronomy. Thanks instead, it is in Pisces actually fairly close to the Aquarius border. As the decades and centuries pass, due to precession, the First Point of Aries continues to slowly drift backwards along the ecliptic (which is the path the Sun takes through the zodiac constellations) and will eventually cross the border into Aquarius, thus beginning the "Age of Aquarius" ("Hair", anyone?). Because of this precession, all celestial coordinates have to be recalibrated every so often, since the vernal equinox is so important to the system. These recalibrations are typically done every 50 years. Now RA is more complicated to explain than declination was, so I'm going to have to break this explanation up into more than one piece. This is a good place to end Part I of my RA explanation. Reply #73. Apr 27 17, 11:45 AM |
| Mixamatosis
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I wasn't blaming every bad weather event on global warming. I've noticed a trend that's getting more pronounced and was quoting just one example. Photosynthesis will be reduced by the desertification of the land, and the shrinking of the Amazon rain forest, both of which are related to man's activity. The Cretaceous may have had higher carbon dioxide but man wasn't around then. It's not just the Chinese who fear rising sea levels but also some island nations and low lying nations like Bangladesh. In the Cretaceous also there weren't people around creating pollution, and acid rain which spoils the planet. There weren't men around killing and threatening the extinction of animals through loss of habitat. Reply #74. Apr 27 17, 1:16 PM |
| Mixamatosis
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There has been a scientific measurement of temperature rises over time which shows that the climate is warming up. It may not turn into Venus but it doesn't have to to create effects that are quite unpleasant and dangerous for mankind. Those responsible for most of it aren't yet the ones suffering the most (except occasionally) so they can afford to wash their hands like Pontius Pilate and say "nothing to do with me" but it will affect them eventually. Already there are more effects in the USa from hurricanes and floods. Reply #75. Apr 27 17, 1:20 PM |
| brm50diboll
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I've said what I have to say on that topic. I predict the nice islanders of the Maldives and Kiribati will still be worried about it 5O years from now and the Chinese Spratly island bases will be fully operational. The use of fossil fuels then will still be around, but reduced. World temperatures will be 0.3°C higher than today and some people will still be expecting an apocalypse from every drought, heat wave, and hurricane that happens then. Then we (or whoever) can make predictions for the next 50 years. Meantime, invest in air conditioning. It's a growth industry. Reply #76. Apr 27 17, 2:48 PM |
| Mixamatosis
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I wish we were both around in 50 years time to check out your predictions, but sadly someone else will need to check for us - the next generation if they remember those predictions at all :( Reply #77. Apr 28 17, 8:54 AM |
| Mixamatosis
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Air conditioning makes me feel unwell. I'll just have to move northwards to a warmer Scotland - a much nicer prospect. Reply #78. Apr 28 17, 8:57 AM |
| Mixamatosis
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Yay! Knowing how long the sun will last has helped me to answer a fun trivia quiz question. Reply #79. Apr 29 17, 1:31 PM |
| brm50diboll
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Very good, Mix! Reply #80. Apr 29 17, 2:59 PM |
526 replies. On page 4 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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