How well do you actually know it? One of the interesting things about temperature is that you can't trust your sense of touch. Notice how you can feel a piece of metal or glass in a room (at normal temperature 70 F) and it feels cool? It's actually the same temperature as the air! It's actually quite a tricky concept.
Temperature is measured by the average kinetic energy of particles in a given area at thermodynamic equilibrium. What this means is that the system or object one is measuring must not be subject to temperature changes at the time, i.e. something taken out of a refrigerator and put into a warmer room. It can be measured if your time interval is infinitely small, otherwise its temperature is constantly changing until it reaches equilibrium with its environment. Kinetic energy is the rate at which the particles in a system are moving. This is difficult to accept as you can imagine, because one doesn't think of iron atoms jumping around.
So why do things like glass and metals feel much cooler when you touch them? It is due to how packed together the molecules are. Think of it as if you are touching exponentially larger amounts of molecules than when your body touches air. Touching all these molecules at once makes heat transfer from your body to the glass very quickly. This sensation of heat leaving your body (to bring the other body into thermodynamic equilibrium) very quickly provides the feeling of cold. There are much fewer molecules flying around in air than in a solid. So, on a planet with a thicker atmosphere, heat would be transferred from or to your body much quicker. Of course, it also depends on how different the two temperatures are. A metal at 0 F will feel extremely cold and the rate of heat transfer will be much faster than one at 80 F. It also works in reverse with hot metals, as you all might have noticed.
Another thing to think about is touching a pool of water with your hand. It feels relatively nice. Then you jump in and are shocked by how cold it is. This is again because water is much more tightly condensed than air, and your body is losing heat much faster than standing in the same temperature air. The amount of water molecules you are touching with your hand also provides the temperature to not feel too bad, but your entire body submerged will lose heat much quicker.
Hopefully all of that is clear! Thanks for reading
Thursday, March 31, 2011
Monday, March 28, 2011
Sorry no post today guys
Have a super fun thermo test tomorrow and as Arnold Sommerfeld puts it...
“Thermodynamics is a funny subject. The first time you go through it, you
don’t understand it at all. The second time you go through it, you think you
understand it, except for one or two small points. The third time you go
through it, you know you don’t understand it, but by that time you are so
used to it, it doesn’t bother you any more.” – Arnold Sommerfeld
He was also nominated for a nobel prize a record 81 times (never won). Six of his students won nobel prizes.
So yeah, I need to study :(
“Thermodynamics is a funny subject. The first time you go through it, you
don’t understand it at all. The second time you go through it, you think you
understand it, except for one or two small points. The third time you go
through it, you know you don’t understand it, but by that time you are so
used to it, it doesn’t bother you any more.” – Arnold Sommerfeld
He was also nominated for a nobel prize a record 81 times (never won). Six of his students won nobel prizes.
So yeah, I need to study :(
Sunday, March 27, 2011
The Power of Cold
Due to the interest in Cryogenics from the previous post, I will now discuss extremely low temperatures and their applications.
First I want to talk about super low temperatures, not actual Cryogenics. Don't worry, it isn't a history lesson. Bose (yes the same guy with the particle named boson) and Einstein (Einsteinium, right!?) proposed after working together that at extremely cold temperatures (near absolute zero) a certain behavior of particles would happen. This is called the Bose-Einstein condensate. Normally, as most of you know, gases move around chaotically in all directions (this is what provides atmospheric pressure, atoms hitting your skin constantly bumping around). However, their theory proposed atoms would move as if you were holding a bunch of pieces of string and waving them together (a uniform wave motion).
In 2001 3 scientists shared the Nobel prize in Physics, 2 from CU Boulder, CO and one from MIT for being the first to demonstrate this condensate. Know what temperature it took to observe it? 1 billionth of 1 degree Kelvin (1 x 10^-9). To fully understand how close that is, they gave the following analogy. If the distance from London to Colorado were the last 1 degree K, they got within a pencil lead's thickness of absolute zero. That's very cold! They did it by keeping the gas within a magnetic field, amongst other things.
But, here is what is really cool about it. Light always moves at 2.9979 x 10^8 m/s in a vacuum, but when it passes through a medium of any kind it has to 'energize' and then pass from one atom to another, so the observed speed is slower. However, it is still moving at the 2.9979 x 10^8 m/s, it just pauses at each atom. Hopefully that makes sense. Now, it was so cold, that light actually passed through the condensate at the speed of a bicycle! That is completely insane. Scientists are now looking at ways to use this, including things such as data storage within light itself due to being able to almost suspend it. Fascinating!
Now onto Cryonics. As some of you may know, in the US and most other parts of the world you have to be legally dead before you are allowed to be frozen. The temperature at which they do it prevents the body from breaking down and incurring further tissue damage (the boiling point of liquid N). One of the first problems, was crystallization of water between cells. Water is a polar molecule and thus has an interesting property all of you are aware of but might not understand. Ice expands and is less dense than water (thus floats). It is caused because the water molecules form circular type chains with space between them rather than all crunched up like liquid water. Well, that type of thing happening in your body is obviously bad.
So, in 1990 some scientists invented something that prevents the freezing of water between cells to help preserve transplant organs. This substance is called a vitrification fluid. It works fine on many tissues, but the brain has more sensitive tissues, so the effects are not completely understood. Animal brains have survived, but characteristics of personality and memory recall are unknown. Additionally, loading the body with vitrification fluid can be bad. In large quantities it is known to be toxic. How toxic? We don't know, because no one has been frozen and woken up.
Regardless, it is believed that by the time the much more complex medical issues which caused the individual to die are solved, the vitrification toxicity and/or cellular damage will be no problem. Works for me, since I'd rather be 150 years in the future anyways :)
Comments welcome as always!
First I want to talk about super low temperatures, not actual Cryogenics. Don't worry, it isn't a history lesson. Bose (yes the same guy with the particle named boson) and Einstein (Einsteinium, right!?) proposed after working together that at extremely cold temperatures (near absolute zero) a certain behavior of particles would happen. This is called the Bose-Einstein condensate. Normally, as most of you know, gases move around chaotically in all directions (this is what provides atmospheric pressure, atoms hitting your skin constantly bumping around). However, their theory proposed atoms would move as if you were holding a bunch of pieces of string and waving them together (a uniform wave motion).
In 2001 3 scientists shared the Nobel prize in Physics, 2 from CU Boulder, CO and one from MIT for being the first to demonstrate this condensate. Know what temperature it took to observe it? 1 billionth of 1 degree Kelvin (1 x 10^-9). To fully understand how close that is, they gave the following analogy. If the distance from London to Colorado were the last 1 degree K, they got within a pencil lead's thickness of absolute zero. That's very cold! They did it by keeping the gas within a magnetic field, amongst other things.
But, here is what is really cool about it. Light always moves at 2.9979 x 10^8 m/s in a vacuum, but when it passes through a medium of any kind it has to 'energize' and then pass from one atom to another, so the observed speed is slower. However, it is still moving at the 2.9979 x 10^8 m/s, it just pauses at each atom. Hopefully that makes sense. Now, it was so cold, that light actually passed through the condensate at the speed of a bicycle! That is completely insane. Scientists are now looking at ways to use this, including things such as data storage within light itself due to being able to almost suspend it. Fascinating!
Now onto Cryonics. As some of you may know, in the US and most other parts of the world you have to be legally dead before you are allowed to be frozen. The temperature at which they do it prevents the body from breaking down and incurring further tissue damage (the boiling point of liquid N). One of the first problems, was crystallization of water between cells. Water is a polar molecule and thus has an interesting property all of you are aware of but might not understand. Ice expands and is less dense than water (thus floats). It is caused because the water molecules form circular type chains with space between them rather than all crunched up like liquid water. Well, that type of thing happening in your body is obviously bad.
So, in 1990 some scientists invented something that prevents the freezing of water between cells to help preserve transplant organs. This substance is called a vitrification fluid. It works fine on many tissues, but the brain has more sensitive tissues, so the effects are not completely understood. Animal brains have survived, but characteristics of personality and memory recall are unknown. Additionally, loading the body with vitrification fluid can be bad. In large quantities it is known to be toxic. How toxic? We don't know, because no one has been frozen and woken up.
Regardless, it is believed that by the time the much more complex medical issues which caused the individual to die are solved, the vitrification toxicity and/or cellular damage will be no problem. Works for me, since I'd rather be 150 years in the future anyways :)
Comments welcome as always!
Saturday, March 26, 2011
Time Travel
I got a request to do this and I listen to the people!
Firstly, time travel backwards is generally accepted as impossible. Excluding the fact the object being transported (you) has mass, light speed is the cosmic speed limit. To go backwards in time you need to go faster than light or use something like a worm hole. Worm holes do exist, but they are smaller than a single atom. Expanding them through some futuristic technique may be possible, but their existence will be ended almost immediately by (it is thought by people such as Steven Hawking) radiation feedback. That is, radiation going through the worm hole, out the other side, and back through over and over again till it builds up sufficiently largely to destroy the worm hole. A similar concept is that screeching sound from amps you get when sound is going through the microphone and projected by the speakers so loudly that it is again being picked up by the microphone and projected a second time.
Time travel into the future is allowed for, however, and has even been done, albeit not very far. There are two ways to do it from Einstein's theories of relativity. One is via the mass of another much more massive object and the other is via velocity. Using the first method, an extremely large mass would be required, such as a black hole. If one were inside a ship on the edge of the event horizon of a black hole, time dilation would occur. Not only would this be extremely dangerous, the outcome is theoretically about only 4 seconds of time per second into the future (so 1 year around the black hole = 4 years on earth).
The second option is via a large amount of velocity. This is the best hope for traveling into the future. If a ship could get to 99.9% of the speed of light, which may be possible in the future, hundreds of years would pass on earth for every 1 year on board the vessel. Interestingly, Hawking explained that a ship such as this would take about 6 years to get up to speed. What he didn't say is that it completely depends on the mass of the ship itself and the amount of power moving it. If the ship were much less massive, it would take much less time to accelerate to speed. Essentially, his calculation is meaningless. We have no idea how massive such an object would be, nor the amount of power possible to get out of it. Sergei Avdeyev has traveled about 20 milliseconds into the future from his extremely long stay on the Mir space station.
I would have to recommend cryogenics as the only method of 'time travel' for the immediate future. Of course, once you are frozen you cannot be woken until that little detail is figured out :)
Comments welcome as always!
Firstly, time travel backwards is generally accepted as impossible. Excluding the fact the object being transported (you) has mass, light speed is the cosmic speed limit. To go backwards in time you need to go faster than light or use something like a worm hole. Worm holes do exist, but they are smaller than a single atom. Expanding them through some futuristic technique may be possible, but their existence will be ended almost immediately by (it is thought by people such as Steven Hawking) radiation feedback. That is, radiation going through the worm hole, out the other side, and back through over and over again till it builds up sufficiently largely to destroy the worm hole. A similar concept is that screeching sound from amps you get when sound is going through the microphone and projected by the speakers so loudly that it is again being picked up by the microphone and projected a second time.
Time travel into the future is allowed for, however, and has even been done, albeit not very far. There are two ways to do it from Einstein's theories of relativity. One is via the mass of another much more massive object and the other is via velocity. Using the first method, an extremely large mass would be required, such as a black hole. If one were inside a ship on the edge of the event horizon of a black hole, time dilation would occur. Not only would this be extremely dangerous, the outcome is theoretically about only 4 seconds of time per second into the future (so 1 year around the black hole = 4 years on earth).
The second option is via a large amount of velocity. This is the best hope for traveling into the future. If a ship could get to 99.9% of the speed of light, which may be possible in the future, hundreds of years would pass on earth for every 1 year on board the vessel. Interestingly, Hawking explained that a ship such as this would take about 6 years to get up to speed. What he didn't say is that it completely depends on the mass of the ship itself and the amount of power moving it. If the ship were much less massive, it would take much less time to accelerate to speed. Essentially, his calculation is meaningless. We have no idea how massive such an object would be, nor the amount of power possible to get out of it. Sergei Avdeyev has traveled about 20 milliseconds into the future from his extremely long stay on the Mir space station.
I would have to recommend cryogenics as the only method of 'time travel' for the immediate future. Of course, once you are frozen you cannot be woken until that little detail is figured out :)
Comments welcome as always!
Friday, March 25, 2011
Entropy, how I loathe thee
So, isentropic processes are pretty cool. It's where the entropy in state 1 is equal to the entropy in state 2, or no change in it, basically. Unfortunately, no such process exists. It's only an idealization by engineers to simplify problems where entropy change is negligable. And trust me, dealing with entropy is a serious pain. I can upload pictures of homework pages long for a single problem solving for it :(
Entropy, and thus, disorder, always increases in the universe whenever energy is being used. What exactly does that mean? Here's a simple example. Say you have a jar of various sized rocks with different densities (mass/volume) in no particular order throughout. If you shake the jar either with your hands or a machine, the rocks will arrange themselves so the highest density larger rocks are on the bottom and the smaller rocks are at the top. That seems to be more ordered, doesn't it? So how can entropy increase?
The answer is that even if you have a process which provides ideal work (also an idealization and impossible) or 100% efficiency for the energy into the system, it still will take more energy to get the rocks back into their original positions. So, entropy has increased even though the rocks appear to be more ordered! This, and of course the fact the process you use (your body or a machine) to shake the rocks also increases the entropy.
Of course, eventually the universe will be filled with so much entropy the energy required to get useful work done will be impossible. Interestingly, proton half-life has been measured to be about 10^40 years. I wonder if the protons will decay before the entropy wins!? Everything in the universe has a death date, it seems. Supermassive black holes will be the last thing to go at 10^80 years. Luckily for those black holes that's a ridiculously long time. Maybe vamps will still be around, they are immune to suffocation and freezing, right?
Comments appreciated and thanks for reading!
Have some future posts lined up, got a request to do something on time travel and I will be doing a piece about this awesome idea I had for a moon base on Europa, and future civilizations view of the universe!
Entropy, and thus, disorder, always increases in the universe whenever energy is being used. What exactly does that mean? Here's a simple example. Say you have a jar of various sized rocks with different densities (mass/volume) in no particular order throughout. If you shake the jar either with your hands or a machine, the rocks will arrange themselves so the highest density larger rocks are on the bottom and the smaller rocks are at the top. That seems to be more ordered, doesn't it? So how can entropy increase?
The answer is that even if you have a process which provides ideal work (also an idealization and impossible) or 100% efficiency for the energy into the system, it still will take more energy to get the rocks back into their original positions. So, entropy has increased even though the rocks appear to be more ordered! This, and of course the fact the process you use (your body or a machine) to shake the rocks also increases the entropy.
Of course, eventually the universe will be filled with so much entropy the energy required to get useful work done will be impossible. Interestingly, proton half-life has been measured to be about 10^40 years. I wonder if the protons will decay before the entropy wins!? Everything in the universe has a death date, it seems. Supermassive black holes will be the last thing to go at 10^80 years. Luckily for those black holes that's a ridiculously long time. Maybe vamps will still be around, they are immune to suffocation and freezing, right?
Comments appreciated and thanks for reading!
Have some future posts lined up, got a request to do something on time travel and I will be doing a piece about this awesome idea I had for a moon base on Europa, and future civilizations view of the universe!
Thursday, March 24, 2011
5% of Arizona can power 100% of the US?
Well, kind of.
I saw this on the latest episode of Real Time with Bill Maher (which is a really funny and informative show). He laid out this statistic claiming solar panels placed in the Arizona desert (where the sun always shines), would provide enough power for the entire United States.
Okay, yeah, that's true if 100% of the power could be transmitted throughout the United States. Transferring power long distances isn't exactly easy. Some of the power is lost over long distances, especially when we are talking about the entire US!
This on top of the economic barriers. One such barrier is the fact we'd need to build an entire infrastructure to handle it. Lots of cash the government does not have. Secondly, after such a structure is built, tons of jobs would be lost in power plants throughout the US. Thirdly, no one would make money from the actual power generation. The only revenue anyone gets would be from the companies tasked with repairing and maintaining the network itself.
Because everyone has to make money to perpetuate the economy, in addition to the massive technological barriers (which are being worked on), I don't see such a system anytime in the near future, unfortunately.
I still like using water treatment plants, what do you guys think?
I saw this on the latest episode of Real Time with Bill Maher (which is a really funny and informative show). He laid out this statistic claiming solar panels placed in the Arizona desert (where the sun always shines), would provide enough power for the entire United States.
Okay, yeah, that's true if 100% of the power could be transmitted throughout the United States. Transferring power long distances isn't exactly easy. Some of the power is lost over long distances, especially when we are talking about the entire US!
This on top of the economic barriers. One such barrier is the fact we'd need to build an entire infrastructure to handle it. Lots of cash the government does not have. Secondly, after such a structure is built, tons of jobs would be lost in power plants throughout the US. Thirdly, no one would make money from the actual power generation. The only revenue anyone gets would be from the companies tasked with repairing and maintaining the network itself.
Because everyone has to make money to perpetuate the economy, in addition to the massive technological barriers (which are being worked on), I don't see such a system anytime in the near future, unfortunately.
I still like using water treatment plants, what do you guys think?
Wednesday, March 23, 2011
hydrogen fueled cars, why not?
I was once excited about hydrogen powered cars as a green solution like many of you probably are. Hydrogen is the most abundant element in the universe and readily available here, no problem. It's also not expensive to produce. Hydrogen fuel cells work quite well. Iceland currently powers many buses in its transportation system using it (in fact the entire country is like a green experiment using all kinds of technologies like geothermal plants, etc).
But... the problem for the rest of the world is this:
We have a MASSIVE infrastructure of gas stations now that would all need to be converted to expend hydrogen and the cost would be staggering. Additionally, because hydrogen is the smallest element it readily escapes its enclosures unless sufficiently pressurized (it requires a ton of pressure). The hydrogen 'tanks' in cars have to be specially manufactured to be highly pressurized as well, to hold the fuel.
Well, that put a damper on things, however, something exciting that's emerging are ways to contain the hydrogen at 1 atmosphere (regular pressure). One research team discovered chicken feathers of all things have nano-pores that hydrogen readily will lodge within. Essentially, they heat the feathers up to condense the material into a fluff, if you will, and then that may be placed inside a tank to hold the hydrogen very cheaply. Chicken feathers are a very cheap commodity, obviously. In addition to that, carbon nanotubes can be used. It was not thought to be cost effective until recently. A chemical engineer in CA discovered that putting waste plastic bags (like grocery bags) into a small reactor and heating them up would produce pure nanotubes extremely cheaply. The exact technical specifications required are unknown to me, but it seems they don't need any special order (assuming the chicken feathers could be dumped into a tank, why not nanotubes?).
Very exciting!
But... the problem for the rest of the world is this:
We have a MASSIVE infrastructure of gas stations now that would all need to be converted to expend hydrogen and the cost would be staggering. Additionally, because hydrogen is the smallest element it readily escapes its enclosures unless sufficiently pressurized (it requires a ton of pressure). The hydrogen 'tanks' in cars have to be specially manufactured to be highly pressurized as well, to hold the fuel.
Well, that put a damper on things, however, something exciting that's emerging are ways to contain the hydrogen at 1 atmosphere (regular pressure). One research team discovered chicken feathers of all things have nano-pores that hydrogen readily will lodge within. Essentially, they heat the feathers up to condense the material into a fluff, if you will, and then that may be placed inside a tank to hold the hydrogen very cheaply. Chicken feathers are a very cheap commodity, obviously. In addition to that, carbon nanotubes can be used. It was not thought to be cost effective until recently. A chemical engineer in CA discovered that putting waste plastic bags (like grocery bags) into a small reactor and heating them up would produce pure nanotubes extremely cheaply. The exact technical specifications required are unknown to me, but it seems they don't need any special order (assuming the chicken feathers could be dumped into a tank, why not nanotubes?).
Very exciting!
Tuesday, March 22, 2011
Supercritical water to save planet?
Hey guys,
I recently saw a program that detailed a water treatment plant in Cork, Ireland (run by a company called Supercritical fluids which you may look up) that was using this amazing property of water to treat sludge water and generate energy.
Bear with me here. Essentially with sufficient pressures (about 30,000 PSI) and high enough temperatures (about 700 F) water enters a 4th state beyond gas/liquid/solid. That state, of course, is called supercritical. What it does is break down all organic compounds (human waste & pharmaceuticals) giving 99.99% pure water and 99.99% pure phosphorus (+ some CO2) in the output stream. This alone is very important. There is a huge clean water shortage coming in the near future and many places are struggling to remove the massive amount of pharmaceuticals from water now (giving rise to fish born with both sexual organs, for instance).
However, the really exciting thing is they are also powering 500,000 homes with 100% clean energy as well! All these compounds in supercritical water break their chemical bonds (which holds large potential energy). This nets a sizable exothermic reaction (meaning heat is released) in the form of super heated steam, which then functions as power plants normally do. Nuclear and coal plants generate steam to turn turbines which generates electric power.
Very exciting stuff!
I recently saw a program that detailed a water treatment plant in Cork, Ireland (run by a company called Supercritical fluids which you may look up) that was using this amazing property of water to treat sludge water and generate energy.
Bear with me here. Essentially with sufficient pressures (about 30,000 PSI) and high enough temperatures (about 700 F) water enters a 4th state beyond gas/liquid/solid. That state, of course, is called supercritical. What it does is break down all organic compounds (human waste & pharmaceuticals) giving 99.99% pure water and 99.99% pure phosphorus (+ some CO2) in the output stream. This alone is very important. There is a huge clean water shortage coming in the near future and many places are struggling to remove the massive amount of pharmaceuticals from water now (giving rise to fish born with both sexual organs, for instance).
However, the really exciting thing is they are also powering 500,000 homes with 100% clean energy as well! All these compounds in supercritical water break their chemical bonds (which holds large potential energy). This nets a sizable exothermic reaction (meaning heat is released) in the form of super heated steam, which then functions as power plants normally do. Nuclear and coal plants generate steam to turn turbines which generates electric power.
Very exciting stuff!
Tuesday, March 15, 2011
first entry!
I've seen a lot of documentaries and youtube videos lately about economic collapse in the world. Normally, it would be easy to brush off most of these as conspiracy theorist type propaganda. However, a lot of them seem to based not really on speculation, but fact. There are generally 3 main postulates on why collapse is coming:
1) peak oil - when the maximum amount of oil that can be produced is being produced. this is happening now. Not much more oil can be produced per day than is being produced now. As demand rises in other developing countries and the supply stays constant, the price goes up, clearly.
2) rising debt levels - every country in the world is now wracked in debt, and this can only go up. There is no possible way to pay back the money, because it doesn't exist. Essentially, a government gets a 1000$ loan from its "Federal Reserve" or central bank. The central bank then wants the money back + 0.005% interest, or whatever it may be. But that central bank also prints the money. Thus, they print the 1000$ but the 0.0005% does not exist. Simple concept.
3) water shortages - many areas of the world are short on clean water already, and that is set to increase. A good example is a massive underground water supply in the mid-west of the US. Nothing is replenishing the water supply, but it is being used. It will be sort of a problem when that runs out!
I've argued with a friend of mine about the resource based economy proposed in the movie Zeitgeist: Moving Forward (good watch, by the way). He considers himself a pure capitalist (where you let the banks fail that fail instead of bailing them out). He certainly does not agree with me about what should happen after collapse, but he does agree that there will be one. He also recognizes the threat of peak oil and water shortages. You know it's scary when two people on opposite ends of the spectrum agree on the conclusion.
Good movies to watch (by all means be as skeptical as you want!)
1) prophets of doom
2) zeitgeist: moving forward
3) collapse
I'm interested in peoples comments even if they comment 5 months from now
1) peak oil - when the maximum amount of oil that can be produced is being produced. this is happening now. Not much more oil can be produced per day than is being produced now. As demand rises in other developing countries and the supply stays constant, the price goes up, clearly.
2) rising debt levels - every country in the world is now wracked in debt, and this can only go up. There is no possible way to pay back the money, because it doesn't exist. Essentially, a government gets a 1000$ loan from its "Federal Reserve" or central bank. The central bank then wants the money back + 0.005% interest, or whatever it may be. But that central bank also prints the money. Thus, they print the 1000$ but the 0.0005% does not exist. Simple concept.
3) water shortages - many areas of the world are short on clean water already, and that is set to increase. A good example is a massive underground water supply in the mid-west of the US. Nothing is replenishing the water supply, but it is being used. It will be sort of a problem when that runs out!
I've argued with a friend of mine about the resource based economy proposed in the movie Zeitgeist: Moving Forward (good watch, by the way). He considers himself a pure capitalist (where you let the banks fail that fail instead of bailing them out). He certainly does not agree with me about what should happen after collapse, but he does agree that there will be one. He also recognizes the threat of peak oil and water shortages. You know it's scary when two people on opposite ends of the spectrum agree on the conclusion.
Good movies to watch (by all means be as skeptical as you want!)
1) prophets of doom
2) zeitgeist: moving forward
3) collapse
I'm interested in peoples comments even if they comment 5 months from now
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