Because it's been obsolete for half a century. The insistence of the US on using archaic systems of measurement, despite the substantial extra difficulty of calculation and attendant errors resulting in the occasional loss of space probes and the like, is a source of continuous amusement and frustration for the rest of the world.
Great, another metric-supremacist jumping up out of nowhere to bash non-metric units.
Listen, the metric system had some great ideas - using only one metric for all spatial divisions is one - but you got ahead of yourself, got half-assed, and have this insane obsession with a useless scaling factor (10).
The meter isn't bad; it's basically a yard. But then you went crazy and tried to related all of your measurements to the Earth, which is just this unnecessary obsession that has no actual intrinsic value. Why is it important that a unit volume of water have a unit mass of weight? Why is it important that there be an even 100 degrees between the freezing and boiling points of water? It's not! You could have chosen any arbitrary weight and temperature baselines and it would have been basically the same.
And then you did a shit job of it! The density of water is 0.997 g/ml! Measuring the Earth to determine the meter was silly all along, and you ended up redefining the triple point of water to 0.01 degree Celsius because it was too hard to fix the discrepancy by then! You started off with these supposedly noble goals, and then got half-assed because it was too hard to correct your earlier mistakes. Sound familiar?
Meanwhile, you've abandoned the archaic units of measure's reliance on powers of two to fetishise powers of ten! (On a computer programming forum, how can you defend this?) Common units are littered in powers of two because factors of two and four make for really convenient subdivisions. Four cups in a quart, four quarts in a gallon, those are very useful subdivisions. Eight furlongs in a mile, sixteen ounces in a pound. Binary divisions produce very useful natural units at human scales. Decimal divisions let an idiot multiply one number by a very large powers of ten easily. Which do you think is really more important?
Strange to find that even in a enlightened place like HN, there abound much support for continued usage of archaic imperial units.
As I see it, since the vast majority of the world is using metric/SI units it behooves the US to change sooner or later.
I think tech/silicon valley should be using their influence with Washington to lobby for these changes. We should be asking each of the presidential candidates in elections what is their stand on this. IIRC, Bernie Sanders had promised that he would take US to metric system if elected.
Meters vs feet is an obvious choice but Fahrenheit actually makes a lot of sense for day to day use. 0-100 (0 being the coldest most people regularly experience, 100 the hottest) maps well to human senses while Celsius has half the precision and the same range is an unintuitive -17 to 37. Celsius is obviously far superior for thermodynamics calculations but not many of us do that regularly.
I'm not saying we shouldn't have switched over decades ago, but I think it's good to understand the context of such decisions.
For starters, if you arbitrarily round Fahreinheit numbers up or down (which you did to get that 0-100 range), you need to do the same with Celsius. So it'd be -20-40, which is a lot less un-intuitive.
But also, that this range is what "most people regularly experience" is also rather arbitrary. I have regularly experienced winters below -20 C, for example, but I've only seen +40 C once. The truth is, most people will experience a range of temperatures that's not going to be nice and round numbers in either scale, so why fixate on it?
I should add the caveat *in the United States. It would obviously be a pretty dumb comparison for Singapore or Reykjavík. I'd also add that the 10s in Fahrenheit also make nice comfort delimiters. 20 is frigid, 30 is ~freezing, 40 is cold, 50 is cool, 60 is warm, 70 is room temp, 80 is hot, 90 is excessively hot, 100 is oppressive. Again, obviously you can do the same thing with the 5s in Celsius but it does work nicely for the average person.
I'm not really saying this is better than Celsius, just that it's understandable why it's not changing as quickly as some would like. I will say that the industries that have specific reason switched fairly quickly. For instance, aviation uses feet, inHg, statute+nautical miles but does temperature in Celsius because pilots overwhelmingly care about whether it's above or below freezing outside.
I think it is now a question of whether the US should follow what the rest of the world follows or not. In the interest of avoiding miscommunication it better for US to change.
As a counterpoint, one of my favorite things about US (and, really, Anglo) culture is that we're totally okay with things not being neat and tidy. Just take a look at English. It's a beautiful mess of a language.
Sorry, it's not obsolete in the U.S., it's used every day by hundreds of millions of people. How is Fahrenheit more difficult to calculate with than Celsius, and what does it have to do with space probes?
>Note to downvoters: This is an objective answer to an objective question. It is not an opinion on the US's use of imperial units.
It's an answer to a question that no one asked. The question was:
>How is Fahrenheit more difficult to calculate with than Celsius, and what does it have to do with space probes?
From the link you provided:
>Specifically, software that calculated the total impulse produced by thruster firings produced results in pound-force seconds. The trajectory calculation software then used these results – expected to be in newton seconds – to update the predicted position of the spacecraft.
It has nothing to do with Farenheit or Celsius. The error was with the representation of force, not temperature.
Indeed it has nothing to do with temperature scales, which is why I made sure to quote the original sentence from kragen which was also not specifically about temperature scales but general "archaic systems of measurement".
It has absolutely nothing to do with everyday temperature scales, none of which have any of the advantages that metric units for distance/mass/etc. have. You might as well be deriding the US for using a different shoe size scale than Europe.
I can't speak for all of US but at least in Midwest, in the circles I grew up it has always been an attitude or US vs the rest. Mention the metric system to a construction worker and he'll tell you to get the hell lost. US culture values individual accomplishments and self-direction so there tends to manifest an us vs them mentality. Having a unique measurement system helps support that mentality so I really don't see any change coming any time soon in regards to switching to the metric system.
It isn't any slower than using celsius, especially with modern calculators and computers. Nobody cares about saving 3 seconds out of an hour of hand calculated mathematics when nobody does those kinds of calculations by hand anymore.
And the same space probe loss could have happened just the same with pure SI units, the problem was somebody didn't put a unit label and somebody else didn't get clarification and made an assumption. If someone used decimeters without labeling and someone else read it as centimeters, you still failed.
