So, what is the problem with a blackboard? Be precise. Well, a blackboard has so much room on it I can go back some steps, even to the start of a long derivation, without flipping through multiple pages on my beamer. I think it must be very confusing for student having all the information available on the same blackboard. I can just point at the blackboard and say: "You see why we did that back there? Although it seemed a bit strange there, now it has helped us big time to get the result!". This way of using the blackboard might be so clear for students they even may start to understand what you are trying to teach them.
If any piece of code is complex enough to require a comment, make it its own function and comment the function.
That is just hiding your complexety. A massive tree of functions called each one time is as complex as all the code sequencally in one function. Plowing through the massive tree of functions will cost you more time as reading sequentially through your code whit comments at the places you would have created a function.
Software patents that were reviewed by qualified examiners and only granted if they were truly novel and non-obvious would promote science and the useful arts. I think far fewer people would have trouble with the concept if that were the reality -- in that case the intended bargain (the patent makes public the details of an idea that nobody else would have thought of on their own) would apply.
Isn't all software written by the open source community proof of the obviousness of that particular software?
Why does this need a sunshield at all? The article says that the telescope should be parked in the 2nd Lagrangian point L2, which is 1.5 Gm from the Earth and should be permanently shaded from sunlight. Isn't the whole point of sending something to L2 that it is not exposed to the sun? Also, how is the energy supply supposed to work? Anyone out there who can shed some light on these questions?
L2 = 1.5e9 m Sun - L2 = 151e9 m
r_Earth = 6.4e6 m
Maximum size sun for complete shading by earth: r_max = 6.4e6 * 151e9 / 1.5e9 = 644e6 m
r_Sun = 700e6 m
No full shade at L2.
Even more important. The telescope won't be at L2 exactly but use an elliptic orbit around L2 with a major axis of 1.5e9 m and a minor axis of 374e6 m. So earth will not be in front of the sun all the time. http://www.jwst.nasa.gov/orbit.html
Nyh
Re:What are the gotchas with these captchas
on
HTML Encoded Captchas
·
· Score: 2, Insightful
Or just users who have the sitteings for Firefox on 'Alway use my colors' because they don't like the angry fruit salads of most sites.
> Any loon who tries to tell a bunch of kids that (a) Noah's ark was real and (b) There were dinosaurs on it should have their license to teach revoked.
Doh.. use some common sense. Of course the dinosaurs didn't get on the ark: That's how they becamse extinct!;) According to the bible they were on the ark. Noah was told by god to get 2 of ever species on the ark. So if there were dinosaurs at the time of the ark they must have been on the ark otherwise... the bible is not telling the truth! The story missing from the bible is: "After the left the ark T-Rex got very hungry and ate all the other dinosaurs and Mammoths then starved to death.";-)
Note also how he mentions that "very nearly all of the world's 160,000+ glaciers... have never been visited by humankind or measured in detail."....so how does he know they are growing?
He doesn't, and I don't think he said that they were (although there may have been an implication). However, since there is little or no data to show that they're growing, you seem to be taking that to be evidence that they are shrinking, which is just as bad.
In the PDF that comes with the article he says the glaciers are growing including the references. From the PDF:
The snows of Kilimanjaro have been receding. So have the glaciers in Glacier National Park, Washington State, and many other (though not all) mountain glaciers in temperate or equatorial latitudes. However, very nearly all of the world's 160,000+ glaciers (this surprisingly large figure is from the UN's 2001 report) have never been visited by humankind or measured in detail. They are on the high, central plateaux Antarctica and Greenland. The great majority are not melting. They are growing. Climate models did not at first predict the cooling of the Antarctic ice mass, nor the accumulation of additional mass by precipitation, which always falls as snow on the high Antarctic plateau. It is now thought that the annual disappearance of the stratospheric ozone layer over the Antarctic, within the ambit of the circumpolar circulation, may have been responsible for this local cooling. The heavy additional precipitation over Iceland and Greenland which has substantially increased the world's ice mass over the past 30 years is now thought to have arisen from the additional moisture in the atmosphere consequent upon warmer global temperatures. There has been local warming in the Antarctic Peninsula, which accounts for a small fraction of the Antarctic land area, but much of the interior has cooled. Though ice-shelves at the continental periphery have retreated, sea ice has increased (Thompson et al., 2002; Liu et al., 2004), and the trend is increasing (Vyas et al., 2003). The Antarctic sea-ice season is three weeks longer today than in 1979. Between 1986 and 2000 the valleys of the central Antarctic cooled at a rate of 0.7C per decade, with serious ecosystem damage from cold (Doran et al., 2004). Less ice has melted in the current interglacial period (the Holocene) than during the previous interglacial (Anderson et al., 1999). Sidelooking radar interferometry shows that the ice mass in the West Antarctic is growing at a rate estimated at 26.8 gigatons per year, reversing a melting trend that has persisted for 6,000 years (Joughin et al., 2002). There is also evidence for greater ice mass in the East Antarctic (Davis et al., 2005).
I don't know why this keeps being quoted. Try this instead: 'The idea of a global or hemispheric "Medieval Warm Period" that was warmer than today however, has turned out to be incorrect.' http://www.ncdc.noaa.gov/paleo/globalwarming/medie val.html
And this is exactly the data the article tries to prove wrong. From TFA: The first mistake made by Mann et al. and copied by the UN in 2001 lay in the choice of proxy data. The UN's 1996 report had recommended against reliance upon bristlecone pines as proxies for reconstructing temperature, because 20th-century carbon-dioxide fertilization accelerated annual growth and caused a false appearance of exceptional recent warming. Notwithstanding the warning against reliance upon bristlecones in UN 1996, Mann et al. had relied chiefly upon a series of bristlecone-pine datasets for their reconstruction of mediaeval temperatures. Worse, their statistical model had given the bristlecone-pine datasets 390 times more prominence than the other datasets they had used:
To debunk this you will have to debunk his arguments on why the data by Mann is wrong. Not by simply quoting the disputed data and simply saying it is right.
The EU competition commissioner, Neelie Smit-Kroes, will not give in under pressure. She was responsible for bringing down the Dutch coalition government Lubbers II. She had proposed to abolish tax dedution for over 10 km daily commuting. Het own party couldn't agree. She held her ground resulting in the end of the coalition.
I think Microsoft knows by know she will not give in so they are trying other ways to get it's own way. She will be fair. She will make Microsoft to do what she told them to do. And it is clear Microsoft doesn't like that at all.
Somehow the keybord design makes me think back to the good old ZX Spectrum. With nice things like CAPS-schift, Symbol-Shift, small SPACE-key and lots of symbols on every key.
Well, first there's the issue about what children will do when it is pushed on them compared to going out and exploring it. How many kids do you think started smoking because they were offered a cig from a buddy, and how many decided to just start on their own?
So true. Most teenagers will start exploring sexuality with their buddies. There will always be more advanced buddies among them pushing them to do things they are not ready for yet. Just as we tell them smoking is very unhealthy, childeren should be informed about sex by that time so they know what the other is asking for and, hopefully, they will be strong enough to say no! when they won't.
Secondly, "Barely legal sluts in wild gangbang" isn't exactly education about sex and consequences. No and childern won't be interested in stuff like that. But they want to know thing like 'how to kiss', 'is my penis too small?', 'can I get pregnant by...?'. All 'forbidden' words will be available on the good educating sites. So the educating sites will be blocked for sure.
The "Barely legal sluts in wild gangbang" is not targetted at children, they do not own credit cards. They won't turn into bad children when they accidentally see it. The normal healthy reaction will be 'yuk! '. My question still is: Why should children be protected from sexual explicit materials?
More interesting is the article fails completely in explaining why children should be protected from sexual explicit materials. If they are not interested they will just skip it as some rubbish. I have never seen any research proving children are harmed in any way when they are accidentally exposed to sexual explicit materials. However, children will be harmed if they won't be educated about sex and it's sexual consequences.
"Yes, this man is Copernicus's Great-great-great-....-great-grandson. We can see they both have green eyes. This woman is his great-great-...-great-granddaughter, twice removed. We can see by this DNA that they're both left handed. So, of course, these must be is bones!"
This will be very hard. Being a priest, Copernicus didn't have any childern of his own.
Dude, you at least need 11.2km/s to get away from the earth.
Yes, and then you arrive at infinity with speed 0. The 11.2 km/s is the escape velocity from earth. This means: if you start from earth with a velocity of 11.2 km/s (and ignore things like air friction) you will escape earths gravity field and arrive at infinity with speed 0 without using any energy for propulsion.
In the Netherlands most banks have implemented a system like this: 1 go to the banks website 2 enter you account number 3 bank sends you a multi digit (typical 6 to 8 digits) code 4 enable you magic code box with your bank card and a pin number 5 enter the multi digit code from the bank in the magic box 6 send multi digit (6 to 8 digits) response from magic box to bank 7 if all is OK you can go to your account information
At the moment you are authorising payments the banks sends you again a code and you will have to supply the response from your magic box to the bank.
This system is immune for fishing attacks. Every time you log in to your bank account the banks sends you a new multi digit code.
The system is not immune for man in the middle attacks but for large payments my banks asks for an extra authorisation code.
To make the man in the middle attacks realy hard the bank should send the code generated by the magic box if you enter the total amount of money transfered plus the sum of the last (three) digits of the bank accounts the money is transfered to so you can check whether the data you send to the bank has been tampered with before you authorise the transfer. But I am afraid that is too complicated for most users.
I am fairly happy with the system. It is not perfect but it is way better as systems with a list predetermined TAN codes as passwords which are very sensitive to phising attacks.
This technology would render gas stations obsolete. Why would you need to drive to such a station in order to drop a small pellet into your pellet tank? It's completely unnecessary! You could easily buy a bag of these pellets from your local hardware or grocery store, and refill your vehicle in the comfort of your own garage!
Usually I need to refil my vehicle while I am on may way to some destination. I don't use my car to drive to the local hardware store so I can buy pellets to put into my car in the garage.
I would find it really cumbersome to leave the highway, find a grocery or hardware store, park, get my bag of pellets, wait some time in the que at the checkout, put the pellets in my car and drive back to the highway, just to fill up my car with some fuel.
...like "do not think that you, freshly-graduated students, are better than everyone else. It takes more than a degree to really stand out."
Sounds like good advice to me!
I sometimes get the feeling universities are learning factories. In a lot of my classes creativity and curiosity were not appreciated by the lecturers. Even on practicals the mood was 'just do your exercises and don't bother me with strange and weird solutions'.
The reverse is also true. I have teached simulation and moddeling classes to 2nd year students. Most students are only interested in getting their points: Giving a fast student an interesting assignment their first question is: 'Does this count for my grade?', default answer: 'Now it does!'.
If you were lucky there would be one student in a group who would come up with his own proposal of a system to analyse and model as their final assignment.
Steve Jobs is saying curiosity and creativity are very important if you want to make a difference. The sad (or is it good?) thing is most students do not want to make a difference. They just want a good job at a solid firm and a good salary. Taking risks should be avoided in their view.
At atmospheric level, air is: ~73% nitrogen, ~23% oxygen, ~2% carbon dioxide, ~2% other, if I recall correctly, and I don't think that the solubility constants are signifigantly different in salt water to throw off those percentages that much.
You don't recall correctly. The solubility constants of the most important gasses at 20C and p=p0 are: O2: 1.38 E-3 mol/L N2: 0.688E-3 mol/L CO2: 38.8 E-3 mol/L Note all constants are highly dependent of water temperature.
I'm guessing that the Mythbusters team did something incorrectly regarding the focusing of their mirrors. And your link says they used a circular configuration which is only good in limited cases since the light is focused in a line (which isn't really focus) rather than a point. This was parabolic setup which is why he was able to melt plastic and set a rose on fire.
The Mythbusters did all right. Their circular configuration was as circular as the mirror configuration of the Solar Death Ray. All mirrors are in concentric circles from the middle. The The National Solar Thermal Test Facility in the US has a lineair configuration of mirrors.
What matters is whether the mirrors are focused correctly and they were (IMHO). They used a Fresnel setup for their mirrors so al mirrors are in the same plane under different angles. The big difference is the focal length of the mirror array.
For small values there is not much difference in the curve defined by y=0.5x*x (parabola) and y=1-sqrt(1-x*x) (circle). For x smaller as 0.2 the error is less as 1%. That is, for a mirror 2 m diameter and a height difference between rim and centre of 20 cm difference in height would be 2 mm. So don't worry about the difference a parabolic and a convex mirror.
Since we didn't actually see where this star was coming from, the star could have been holding still for a long time while the galaxy far,far away came stampeding past like the wildebeast stampede in Lion King. To us stuck here on earth it would look exactly the same either way. So its not so much tht the star is being ejected, but that it survived the stampede.
Nice theory but incorrect. If you read TFA: "Less than 80 million years were needed for the star to reach its current location, which is consistent with its estimated age.".
If it only was sitting in space waiting for the galaxy to stampede by its age would be much, much higher.
I read somewhere that you only need about 50 digits of pi to describe a circle the size of the observable universe to within the diameter of a proton, let alone a chocolate donut.
Well, let us see: radius universe: about 15e9 lightyears radius proton: 1.2e-15 m
circle with the size of the universe divided by diameter proton: 2*pi*15e9*365*24*3600*300000000/(2*1.2e-1 5)=3.7e41. So 42 digits of pi will do.
We don't need an age verification. We need a nerd verification.
Like: some basic math: solve x'=ax+b some basic physics: a container is filled with an ideal gas. The pressure in the container is exp(pi)E5 Pa, temperature is 54 degrees Fahrenheit. Calculate the pressure in bar when the temperature is changed to 54 degrees Celcius some basic programming: What will be the output of this program: #include <stdio.h> int main(void) {
int i=0;
while(i<10);
{
printf("%i ",i);
}
return 0; }
I think we can come up with some other examples.
Nyh
Note: yes I know the C program has a little problem.
Slashdot Mirror
Nyh
If any piece of code is complex enough to require a comment, make it its own function and comment the function.
That is just hiding your complexety. A massive tree of functions called each one time is as complex as all the code sequencally in one function. Plowing through the massive tree of functions will cost you more time as reading sequentially through your code whit comments at the places you would have created a function.
Nyh
Software patents that were reviewed by qualified examiners and only granted if they were truly novel and non-obvious would promote science and the useful arts. I think far fewer people would have trouble with the concept if that were the reality -- in that case the intended bargain (the patent makes public the details of an idea that nobody else would have thought of on their own) would apply.
Isn't all software written by the open source community proof of the obviousness of that particular software?
Nyh
Why does this need a sunshield at all? The article says that the telescope should be parked in the 2nd Lagrangian point L2, which is 1.5 Gm from the Earth and should be permanently shaded from sunlight. Isn't the whole point of sending something to L2 that it is not exposed to the sun? Also, how is the energy supply supposed to work? Anyone out there who can shed some light on these questions?
L2 = 1.5e9 m
Sun - L2 = 151e9 m
r_Earth = 6.4e6 m
Maximum size sun for complete shading by earth:
r_max = 6.4e6 * 151e9 / 1.5e9 = 644e6 m
r_Sun = 700e6 m
No full shade at L2.
Even more important. The telescope won't be at L2 exactly but use an elliptic orbit around L2 with a major axis of 1.5e9 m and a minor axis of 374e6 m. So earth will not be in front of the sun all the time. http://www.jwst.nasa.gov/orbit.html
Nyh
Or just users who have the sitteings for Firefox on 'Alway use my colors' because they don't like the angry fruit salads of most sites.
Nyh
> Any loon who tries to tell a bunch of kids that (a) Noah's ark was real and (b) There were dinosaurs on it should have their license to teach revoked.
;) ;-)
Doh.. use some common sense. Of course the dinosaurs didn't get on the ark: That's how they becamse extinct!
According to the bible they were on the ark. Noah was told by god to get 2 of ever species on the ark. So if there were dinosaurs at the time of the ark they must have been on the ark otherwise... the bible is not telling the truth! The story missing from the bible is: "After the left the ark T-Rex got very hungry and ate all the other dinosaurs and Mammoths then starved to death."
Nyh
In the PDF that comes with the article he says the glaciers are growing including the references. From the PDF:
The snows of Kilimanjaro have been receding. So have the glaciers in Glacier National Park,
Washington State, and many other (though not all) mountain glaciers in temperate or equatorial
latitudes. However, very nearly all of the world's 160,000+ glaciers (this surprisingly large figure is
from the UN's 2001 report) have never been visited by humankind or measured in detail. They are on
the high, central plateaux Antarctica and Greenland. The great majority are not melting. They are
growing.
Climate models did not at first predict the cooling of the Antarctic ice mass, nor the accumulation of
additional mass by precipitation, which always falls as snow on the high Antarctic plateau. It is now
thought that the annual disappearance of the stratospheric ozone layer over the Antarctic, within the
ambit of the circumpolar circulation, may have been responsible for this local cooling.
The heavy additional precipitation over Iceland and Greenland which has substantially increased the
world's ice mass over the past 30 years is now thought to have arisen from the additional moisture in
the atmosphere consequent upon warmer global temperatures.
There has been local warming in the Antarctic Peninsula, which accounts for a small fraction of the
Antarctic land area, but much of the interior has cooled. Though ice-shelves at the continental
periphery have retreated, sea ice has increased (Thompson et al., 2002; Liu et al., 2004), and the trend
is increasing (Vyas et al., 2003). The Antarctic sea-ice season is three weeks longer today than in 1979.
Between 1986 and 2000 the valleys of the central Antarctic cooled at a rate of 0.7C per decade, with
serious ecosystem damage from cold (Doran et al., 2004). Less ice has melted in the current
interglacial period (the Holocene) than during the previous interglacial (Anderson et al., 1999). Sidelooking
radar interferometry shows that the ice mass in the West Antarctic is growing at a rate
estimated at 26.8 gigatons per year, reversing a melting trend that has persisted for 6,000 years
(Joughin et al., 2002). There is also evidence for greater ice mass in the East Antarctic (Davis et al.,
2005).
Nyh
I don't know why this keeps being quoted. Try this instead: 'The idea of a global or hemispheric "Medieval Warm Period" that was warmer than today however, has turned out to be incorrect.' http://www.ncdc.noaa.gov/paleo/globalwarming/medie val.html
And this is exactly the data the article tries to prove wrong. From TFA:
The first mistake made by Mann et al. and copied by the UN in 2001 lay in the choice of proxy data.
The UN's 1996 report had recommended against reliance upon bristlecone pines as proxies for
reconstructing temperature, because 20th-century carbon-dioxide fertilization accelerated annual growth
and caused a false appearance of exceptional recent warming. Notwithstanding the warning against
reliance upon bristlecones in UN 1996, Mann et al. had relied chiefly upon a series of bristlecone-pine
datasets for their reconstruction of mediaeval temperatures. Worse, their statistical model had given the
bristlecone-pine datasets 390 times more prominence than the other datasets they had used:
To debunk this you will have to debunk his arguments on why the data by Mann is wrong. Not by simply quoting the disputed data and simply saying it is right.
Nyh
Well, if I read the application correctly it can do some of the functionality found in: http://www.euroglot.nl/en/index.html:
Euroglot gives the user: all conjugations and declensions
Conjugations and declensions: * EuroglotOnline also recognizes declined words!
Hmmm, it seems Euroglot has been violating this patent application at least since 1999.
Nyh
The EU competition commissioner, Neelie Smit-Kroes, will not give in under pressure. She was responsible for bringing down the Dutch coalition government Lubbers II. She had proposed to abolish tax dedution for over 10 km daily commuting. Het own party couldn't agree. She held her ground resulting in the end of the coalition.
I think Microsoft knows by know she will not give in so they are trying other ways to get it's own way. She will be fair. She will make Microsoft to do what she told them to do. And it is clear Microsoft doesn't like that at all.
Nyh
The ZX81 didn't have that many shift possibilities as the ZX Spectrum. It was also far less colourfull.
Nyh
Somehow the keybord design makes me think back to the good old ZX Spectrum. With nice things like CAPS-schift, Symbol-Shift, small SPACE-key and lots of symbols on every key.
Nyh
Well, first there's the issue about what children will do when it is pushed on them compared to going out and exploring it. How many kids do you think started smoking because they were offered a cig from a buddy, and how many decided to just start on their own?
...?'. All 'forbidden' words will be available on the good educating sites. So the educating sites will be blocked for sure.
So true. Most teenagers will start exploring sexuality with their buddies. There will always be more advanced buddies among them pushing them to do things they are not ready for yet. Just as we tell them smoking is very unhealthy, childeren should be informed about sex by that time so they know what the other is asking for and, hopefully, they will be strong enough to say no! when they won't.
Secondly, "Barely legal sluts in wild gangbang" isn't exactly education about sex and consequences.
No and childern won't be interested in stuff like that. But they want to know thing like 'how to kiss', 'is my penis too small?', 'can I get pregnant by
The "Barely legal sluts in wild gangbang" is not targetted at children, they do not own credit cards. They won't turn into bad children when they accidentally see it. The normal healthy reaction will be 'yuk! '. My question still is: Why should children be protected from sexual explicit materials?
Nyh
More interesting is the article fails completely in explaining why children should be protected from sexual explicit materials. If they are not interested they will just skip it as some rubbish. I have never seen any research proving children are harmed in any way when they are accidentally exposed to sexual explicit materials. However, children will be harmed if they won't be educated about sex and it's sexual consequences.
Nyh
"Yes, this man is Copernicus's Great-great-great-....-great-grandson. We can see they both have green eyes. This woman is his great-great-...-great-granddaughter, twice removed. We can see by this DNA that they're both left handed. So, of course, these must be is bones!"
This will be very hard. Being a priest, Copernicus didn't have any childern of his own.
Nyh
Dude, you at least need 11.2km/s to get away from the earth.
Yes, and then you arrive at infinity with speed 0. The 11.2 km/s is the escape velocity from earth. This means: if you start from earth with a velocity of 11.2 km/s (and ignore things like air friction) you will escape earths gravity field and arrive at infinity with speed 0 without using any energy for propulsion.
Nyh
In the Netherlands most banks have implemented a system like this:
1 go to the banks website
2 enter you account number
3 bank sends you a multi digit (typical 6 to 8 digits) code
4 enable you magic code box with your bank card and a pin number
5 enter the multi digit code from the bank in the magic box
6 send multi digit (6 to 8 digits) response from magic box to bank
7 if all is OK you can go to your account information
At the moment you are authorising payments the banks sends you again a code and you will have to supply the response from your magic box to the bank.
This system is immune for fishing attacks. Every time you log in to your bank account the banks sends you a new multi digit code.
The system is not immune for man in the middle attacks but for large payments my banks asks for an extra authorisation code.
To make the man in the middle attacks realy hard the bank should send the code generated by the magic box if you enter the total amount of money transfered plus the sum of the last (three) digits of the bank accounts the money is transfered to so you can check whether the data you send to the bank has been tampered with before you authorise the transfer. But I am afraid that is too complicated for most users.
I am fairly happy with the system. It is not perfect but it is way better as systems with a list predetermined TAN codes as passwords which are very sensitive to phising attacks.
Nyh
This technology would render gas stations obsolete. Why would you need to drive to such a station in order to drop a small pellet into your pellet tank? It's completely unnecessary! You could easily buy a bag of these pellets from your local hardware or grocery store, and refill your vehicle in the comfort of your own garage!
Usually I need to refil my vehicle while I am on may way to some destination. I don't use my car to drive to the local hardware store so I can buy pellets to put into my car in the garage.
I would find it really cumbersome to leave the highway, find a grocery or hardware store, park, get my bag of pellets, wait some time in the que at the checkout, put the pellets in my car and drive back to the highway, just to fill up my car with some fuel.
Nyh
This press release of the Danish Univeristy may shed some light on the material:d =%7BE6FF7D39-1EDD-41A4-BC9A-20455C2CF1A7%7D
http://www.dtu.dk/English/About_DTU/News.aspx?gui
Nyh
...like "do not think that you, freshly-graduated students, are better than everyone else. It takes more than a degree to really stand out."
Sounds like good advice to me!
I sometimes get the feeling universities are learning factories. In a lot of my classes creativity and curiosity were not appreciated by the lecturers. Even on practicals the mood was 'just do your exercises and don't bother me with strange and weird solutions'.
The reverse is also true. I have teached simulation and moddeling classes to 2nd year students. Most students are only interested in getting their points: Giving a fast student an interesting assignment their first question is: 'Does this count for my grade?', default answer: 'Now it does!'.
If you were lucky there would be one student in a group who would come up with his own proposal of a system to analyse and model as their final assignment.
Steve Jobs is saying curiosity and creativity are very important if you want to make a difference. The sad (or is it good?) thing is most students do not want to make a difference. They just want a good job at a solid firm and a good salary. Taking risks should be avoided in their view.
Nyh
At atmospheric level, air is: ~73% nitrogen, ~23% oxygen, ~2% carbon dioxide, ~2% other, if I recall correctly, and I don't think that the solubility constants are signifigantly different in salt water to throw off those percentages that much.
You don't recall correctly. The solubility constants of the most important gasses at 20C and p=p0 are:
O2: 1.38 E-3 mol/L
N2: 0.688E-3 mol/L
CO2: 38.8 E-3 mol/L
Note all constants are highly dependent of water temperature.
Nyh
I'm guessing that the Mythbusters team did something incorrectly regarding the focusing of their mirrors. And your link says they used a circular configuration which is only good in limited cases since the light is focused in a line (which isn't really focus) rather than a point. This was parabolic setup which is why he was able to melt plastic and set a rose on fire.
The Mythbusters did all right. Their circular configuration was as circular as the mirror configuration of the Solar Death Ray. All mirrors are in concentric circles from the middle. The The National Solar Thermal Test Facility in the US has a lineair configuration of mirrors.
What matters is whether the mirrors are focused correctly and they were (IMHO). They used a Fresnel setup for their mirrors so al mirrors are in the same plane under different angles. The big difference is the focal length of the mirror array.
For small values there is not much difference in the curve defined by y=0.5x*x (parabola) and y=1-sqrt(1-x*x) (circle). For x smaller as 0.2 the error is less as 1%. That is, for a mirror 2 m diameter and a height difference between rim and centre of 20 cm difference in height would be 2 mm. So don't worry about the difference a parabolic and a convex mirror.
Nyh
Since we didn't actually see where this star was coming from, the star could have been holding still for a long time while the galaxy far,far away came stampeding past like the wildebeast stampede in Lion King. To us stuck here on earth it would look exactly the same either way. So its not so much tht the star is being ejected, but that it survived the stampede.
Nice theory but incorrect. If you read TFA: "Less than 80 million years were needed for the star to reach its current location, which is consistent with its estimated age.".
If it only was sitting in space waiting for the galaxy to stampede by its age would be much, much higher.
Nyh
I read somewhere that you only need about 50 digits of pi to describe a circle the size of the observable universe to within the diameter of a proton, let alone a chocolate donut.
1 5)=3.7e41 .
Well, let us see:
radius universe: about 15e9 lightyears
radius proton: 1.2e-15 m
circle with the size of the universe divided by diameter proton:
2*pi*15e9*365*24*3600*300000000/(2*1.2e-
So 42 digits of pi will do.
42? Where did I see this number before?
Nyh
We don't need an age verification. We need a nerd verification.
Like:
some basic math: solve x'=ax+b
some basic physics: a container is filled with an ideal gas. The pressure in the container is exp(pi)E5 Pa, temperature is 54 degrees Fahrenheit. Calculate the pressure in bar when the temperature is changed to 54 degrees Celcius
some basic programming:
What will be the output of this program:
#include <stdio.h>
int main(void)
{
int i=0;
while(i<10);
{
printf("%i ",i);
}
return 0;
}
I think we can come up with some other examples.
Nyh
Note: yes I know the C program has a little problem.