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The banner of that webpage already shows the helicopter flying.

This CGI is confusing. When it comes to Mars rovers, I never know which images are real or fake. They could at least have a mark in the corner to indicate CGI.

They're all CGI.
That's certainly true when we're talking about images of solitary rovers. Now that they've sent multiple robots to the same location, it's at least possible they could get real pictures of them.
I always wondered how those Mars rover selfies manage to not show the arm holding the camera.
Probably the images have some artifacts near the point where the arm is attached to the body.
Wide angle "lens" (done in software). The cheap security cameras I use at home do it by default. Not as obviously distorted as a real fisheye lens, but still effective.
They can take photos that look as if they were taking by a separate camera but they just move the arm at which the camera is attached around. The arm will be at different positions in different images and they then stitch the photos together excluding the image parts with the arm.

Edit: I found an animation for you that actually shows the process! It's on NASA JPL's Instagram account, though: https://www.instagram.com/p/6k4pUMFbys/

But how could it show the rover in its entirety, including the arm itself?
45 Fahrenheit = 7.2 Celsius

-130 Fahrenheit = -90 Celsius

Why is NASA using those antiquated imperial units in the first place? I thought they'd want to be a force for progress?
It's embarrassing that they don't provide a metric conversion, and also omit the ° sign.

(PS America uses "US customary" or "English" units. Imperial units means the ones after standardization across the British Empire in 1824, which by then did not include the USA.)

It's embarrassing that they aren't pushing to switch the US to the metric system.
I believe it's been tried before, and failed.
The US did switch to the metric system over 45 years ago[1]. Many of us just prefer the customary units for many everyday uses for various reasons. For example, I find degrees Fahrenheit a more sensible choice for representing outdoor temperatures since the degree increments are slightly smaller and the typical outdoor temperature nearly always falls in the positive range. For Celsius, the triple point of water zero is a great reference for lab work, it doesn’t have any particular relevance to deciding what to wear.

A base 12 distance unit also has some pleasant properties.

[1] https://en.m.wikipedia.org/wiki/Metric_Conversion_Act

> Celsius, the triple point of water zero is a great reference for lab work, it doesn’t have any particular relevance to deciding what to wear.

Uh let me do some primary school math for you:

>30 Degrees Celsius: hot/summer weather. 20 Degrees Celsius: warm spring, t-shirt weather. 10 Degrees Celsius: light jacket. 0 Degrees Celsius: literally freezing. Winter clothing. -15 Degrees Celsius: requires heavy & layered clothing to avoid hypothermia and/or frostbite. -30 Degrees Celsius: arctic gear.

Look, the turning point between light clothing and winter clothing is literally built into the system: 0 degrees is the triple point of water as you said so yourself. There are many arguments why the US hasn't seen a wide-scale adoption of metric temperature, but I'd posit that "objective ease of use" isn't it. You lot are just used to a legacy system with all it's warts and it's more convenient to go with the joneses than try to force change. I think trying to advance arguments how it's more convenient is a fools errand because it's literally just force of habit.

I can promise you that the various feet, inches, fluid ounces and other shenanigans are mind-bogglingly confusing for anyone who is used to metric. Doubly so given the very annoying ratios that emerge with square/cubic/volume units.

During Canada's transition to metric in the 1970's a lady called into the local radio station's call in program. She issued a challenge to anyone who supported the English system to call with the answer to this question:

What is 5/8ths of 2 ounces, 4 drams and 5 grains? :-)

She was an immigrant from Czechia and had to learn the British Apothecary system when she arrived in the 1950s. To her credit she had mastered it but it was lunacy.

1 1/4ths ounce, 2 1/2 drams and 3 1/8th grains is what I came up with off the top of my head. Is some additional normalization expected? US customary isn’t as complex in practical use we just use fractions of our units.

Of course there are fun questions like “which ounce?” Not knowing that I don’t think I can do better.

At minimum, 1¼ oz was probably expected to be expressed as 1 oz 2 dr, and so on for the others.

But I understood "2 ounces, 4 drams and 5 grains" to be a single measurement.

An apothecary dram (ʒ) is 60 grains, and an apothecary ounce (℥) is 480 grains, so we have 1205 grains. ⅝ of that is 753⅛ gr, which is 1 ℥ 4 ʒ 33⅛ gr.

I think these measurements would have been in common use by pharmacists ... although [1] says they're still in use some times in the USA, or have only recently fallen out of use.

It's also interesting to see the mixtures of units in common use there. The UK has Imperial units for several daily things (body height and weight, road distance and speed) yet the medical profession actively avoids use of the system -- equipment is only metric. This is to avoid any errors made during conversion, and ensure day-to-day familiarity with the units.

[1] https://nursekey.com/u-s-customary-units-and-the-apothecary-...

But I understood "2 ounces, 4 drams and 5 grains" to be a single measurement.

Correct. Three columns required, similar to the old British money system of Pounds, Shillings and Pence.

I think you’ve missed the point of the post you’re responding to, and even remade it... the imperial system is exactly legacy, and its idiosyncrasies aren’t warts per se—for someone who’s able to use it (ie not an outsider looking in without familiarity//triggered to the point of “primary school” incivility), it has some convenient properties, and we’re quite pleased to keep using it day-to-day, thanks.

(Sidebar: the turning point between very warm and hot is literally built into the system at 100F. If you think 30C is hot, you’ve clearly not spent much time here in the summer... and it doesn’t feel really cold until you’re down around 0F anyway.)

> various feet, inches, fluid ounces and other shenanigans are mind-bogglingly confusing for anyone who is used to metric

This isn’t relevant—no one is asking you lot to change from metric, and it isn’t confusing to our lot. We manage quite easily not to get our minds getting boggled... we’re even able to switch between multiple units, no problem, it’s not as confusing or challenging as you make it sound.

Apologies I was perhaps too much tongue in cheek, there was no offence meant.

On the other hand, you too are arguing against points I haven't made. I'm not saying the imperial system is bad on it's own. I have no opinion on this. Anyone who is used to it will find it intuitive. However, saying that it's somehow objectively more geared for humans is also incorrect, because as I wrote it is exactly as convenient to use for people used to metric as metric is for people used to imperial.

> the turning point between very warm and hot is literally built into the system at 100F. If you think 30C is hot, you’ve clearly not spent much time here in the summer... and it doesn’t feel really cold until you’re down around 0F anyway

Again, this is subjective. 30C is hot for many people in the Nordics, and business as usual for someone in the tropics. The same will apply whether we use the imperial system or not. But I personally have no intuition how 0F or 100F feels like. It's all subjective (how it feels like).

I was merely arguing that trying to lean on subjective/intuitive feel for the units to make a general case of them being useful for daily life is still just subjective. Imperial is intuitive for people who are used to it and highly unintuitive for anyone who isn't. Conversely, metric is intuitive for people who are used to it - even for daily life and imperial is not.

:) and my apologies, too—I didn't mean to be too snarky and irascible.

maybe we can agree that both Celsius and Fahrenheit are subjectively easier to relate to everyday life than Kelvin...

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I'm always confused when people say Fahrenheit is great because it's "more granular" and makes it easier to decide what to wear. Do other people use clothing this differently from me? How many increments worth of clothing variation do you have in your wardrobe?

Based on all conversations I've had so far, it seems Americans just think their intuition being tied to Fahrenheit (because that's what they're familiar with) make Fahrenheit intrinsically more intuitive.

I live in the North West of Germany, so based on the local climate this is how temperature works for me:

180°C/200°C (365°F/392°F): oven temperature; this is a good default for most frozen goods, e.g. store bought frozen pizza

Roughly 100°C (212°F): boiling water; this is what comes out of your kettle

Roughly 60°C (140°F): hot water; anything above this will probably scald you

Above 30°C (86°F): warm summer; without wind chill it's probably going to be humid so loose-fitting clothing is a must

Around 25°C (77°F): warm bordering on hot; above this temperature it's probably going to be annoying indoors without ventilation or AC, a few degrees more and I'll find it hard to focus while working

Roughly 20°C (68°F): "room temperature"; legs and hands may get cold after sitting for prolonged times but otherwise it's warm enough to wear a t-shirt outdoors but too cold for shorts

Around 15°C (59°F): a bit chilly; may feel warmer in spring but below this temperature it's probably getting a bit too cold for t-shirts

Below 10°C (50°F): cold; you should wear a jacket and with a bit of wind it can get uncomfortable

Around 0°C (30°F): freezing point; risk of black ice and there might be snow, so you'll need proper footwear

Below -10°C (14°F): very cold; you probably want to invest in proper winter clothing because those jeans might get a bit chilly

Below -20°C (-4°F): extremely cold; it doesn't get this cold normally so you're probably not equipped to handle this, time to bring out that winter gear you bought for your last skiing vacation

Note that this is aligned with the metric scale because that's what I've grown up with and hence what I've tied my intuitions to. If you looked at the Fahrenheit temperatures in isolation they would seem completely arbitrary so it's not surprising the inverse is true (e.g. 80°F is 26.7°C -- and this also settles the "more increments" argument as Celsius temperatures are usually given with a decimal and rounded in casual conversation).

> Note that this is aligned with the metric scale because that's what I've grown up with and hence what I've tied my intuitions to.

That's a bit unfair. You're coming from Celsius. If someone we're coming from Farenheit, they could round your scale to the nearest tens then complain how Celsius's fractions are so arbitrary for these cutoffs. (Not including your boiling water references since this is about weather.)

That's precisely the point I'm making. I'm presenting the "intuitive" Celsius scale in response to the claim that Fahrenheit is intuitive because my point is that we have the intuition regardless of the exact system of measurement that surrounds us and just tie it to values that feel right and then say the fact these feelings align with those values are evidence that the system is intuitive when there's nothing in those values itself making them more or less intuitive.

E.g. to be pedantic, room temperature is usually given as 19°C (66.2°F) and many prefer 21°C (69.8°F) or even 22°C (71.6°F) and I could have also stated my cut-off for unpleasant warmth as around 27°C (80.6°F). Your intuitive scale likely doesn't perfectly line up with either of the two systems but you project it onto whichever you are used to.

I’ll add to this that Fahrenheit is human-centric by design. Granted he didn’t get it quite right, but 100 degrees F was meant to be average human body temperature.

I’m personally comfortable with both. I prefer customary in the USA and metric in Europe. This is no more uncomfortable for me than speaking English in the USA and one of the other languages I know when in Europe. This might be because I’m native bilingual. I think and dream in both languages.

Edit: Interestingly Americans are quite willing to use metric on a syncretic basis in a way somewhat analogous to how polytheistic religions incorporate foreign beliefs. For example Americans are quite comfortable with the liter as a beverage volume. And certain American subcultures actually use the gram as a subunit of the ounce for small masses.

Sorry, it wasn't clear that you were arguing that they were equally intuitive. It seemed to me you were arguing Celsius is more so.
These scales are both arbitrary. Celsius is super useful if you are concerned with phase transitions of water in the presence of a gas at 101,325 Pa of pressure - it's hard to do much better, really. But what if we wanted to design a scale for measuring the typical range of air temperatures experienced outside in the temperate climates on Earth? You said you are from northwest Germany, which is a fairly temperate climate - to pick an arbitrary city there, the record low in Bremen is -23.6 C and the record high is 37.6 C. So perhaps for our hypothetical scale for Bremen (let's label its units B) a good range would be to set 0 B to -23.6 C and 100 B to 37.6 C to capture this range. In this scale 0 C would end up being 38.6 B and 100 C would end up being 202 B... values that are curiously close to an existing temperature scale.

The B scale would be useful for talking about the outdoor air temperature in Bremen. Would the B temperature scale be useful for talking about atmospheric temperature on Mars? Not any more or less so than C... there's no real inherit advantage to either. The choice you make would likely be based on what your primary audience is more familiar with. If you wanted to force your readers to read a unit that would somehow promote scientific literacy you'd probably go with the Kelvin scale since 0 K is not arbitrary (although the unit magnitude still is).

Sounds like you're from a warm climate. Unfortunately, comfort level is dependent on local temperatures. Canadians who vacation in Florida love the winters, and traipse about in shorts and sandals while the locals are bundled up in toques and sweaters.

86F/30C is nearly miserable

32F/0C is shorts weather if you'll be moving around at all

And I live in balmy Vancouver. But to be fair, our 30 is never dry, and some locals bundle up when it's 15.

> 86F/30C is nearly miserable

> 32F/0C is shorts weather if you'll be moving around at all

That really depends on the wind, humidity and the amount of sunlight. I don't live that far north or south, but I certainly wouldn't consider freezing shorts weather or 30 °C/86 °F miserably hot.

Pleasant 32C Autumn morning.

Shorts and T-Shirt is every-day-of-the-year uniform.

Cairns, Tropical Queensland, Australia.

Mind you, in mid-winter it sometimes gets down to a chilly 12C over-night. (Well, maybe for a few days a year.)

Yeah, that's why I specified my location and climate. Except for things like the boiling and freezing point most of these are highly subjective. My point is that what specific temperatures we align them with is not only subjective but also somewhat arbitrary depending on whichever scale we're used to.

If I lived in a region that uses Fahrenheit, I'd probably have picked values that are nice round numbers in Fahrenheit instead of Celsius.

> Many of us just prefer the customary units for many everyday uses for various reasons.

The switch wasn't effective because there wasn't a concerted effort to to make people switch by the government. They could have easily made it such that weather reports use Celsius in addition to Fahrenheit, speedometers in cars display speed in kilometers per hour by default, etc.

Right now, we have a mix because certain products started using metric on their own (e.g., soft drinks with their 2 liter bottles, car manufacturers using liters to measure engine displacement instead of cubic inches, etc.).

For a variety of reasons, I prefer Fahrenheit over Celsius for everyday temperatures.

But, genuine question, what could possibly be the advantage to using a base 12 unit for measuring distance?

Taking a third or sixth without a repeating decimal. I believe the ancient Mayans used base 60 for similar reasons.

Edit: I misremembered. It was the Babylonians that used base 60.

In what contexts is taking 1/3 or 1/6 a common pattern?
Behind the scenes, they're very likely using metric. For press releases and such, however, it's worth remembering that the primary audience is the American public, and said public - for better or worse - uses those antiquated units.
In addition, when other partners / contractors have failed to use metric when expected, it has caused some grave mission failures!

> The spacecraft encountered Mars on a trajectory that brought it too close to the planet, and it was either destroyed in the atmosphere or escaped the planet's vicinity and entered an orbit around the sun.[2] An investigation attributed the failure to a measurement mismatch between two software systems: metric units by NASA and non-metric ("English") units by spacecraft builder Lockheed Martin.

https://en.wikipedia.org/wiki/Mars_Climate_Orbiter#Cause_of_...

>Behind the scenes, they're very likely using metric.

This isn't true at all, lol. Aerospace in the US has used 'english' measurement from the start. My take on the matter is that all units are arbitrarily defined and flip flopping the units that we already use is a silly idea of progress.

Someone has to flip flop when nations come together to build stuff.
While on the temperature side, I would agree with you (though ideally you would want something that starts at 0 like Kelvin), this is different on the distance and weigh side.

The strength of the metric system is not on the particular dimension of their definition, but lies in the use of a decimal system. That is what makes it superior to the old imperial system and why the scientific community in the US uses it. Using a single base system for all your numbers, and the same base system as the one used in your numbering systems is the only way you can do complex computations without resorting to many magic numbers.

They’re also a government agency under political influences like any other and at the end of the day someone had to make the call on how to communicate with the “plebs”. So Fahrenheit it is.
In the United States we are capable of understanding more than one system of measurement and using the appropriate one for the current situation.
Are you really? I hear people ask for C to F conversion as much as the other way around.
Not to mention the multiple outright disasters that happened exactly because they don't have a good handle on using the appropriate units...
Yes, it’s not hard...I use the reversed digits method:

82F ≈ 28C

61F ≈ 16C

40F ≈ 04C

11F ≈ -11C

First time I hear about it, noticed the accuracy drops off significantly if the last number is >1?

51F ~ 15C

52F ~ 25C

59F ~ 95C?

Subtract 30, divide by 2 works well enough heh

Ha! 59F is a good one :D

Yeah, I should have clarified—this works for those specific combinations...it’s mostly a back of the envelope way to orient yourself in the other system.

>Subtract 30, divide by 2 works well enough heh

That's close enough for most purposes, but (F)5/9-32=(C) provides better precision.

> 82F ≈ 28C

81F ≈ 18C? 83F ≈ 38C?

It... Doesn't work?

The way I do it is count by nines from 32 to get to the temperature I want and then multiply by 5. For example, if I want to know what the corresponding temperature for 70 °F in Celsius, I would do the following:

  0 -> 32
  5 -> 41
  10 -> 50
  15 -> 59
  20 -> 68
So I know the temperature in Celsius is just above 20 °C (21 °C give or take).

To speed up the process, I can use other starting points I know like 10 °C for 50 °F, 35 °C for 95 °F, -15 °C for 5 °F and, of course, at -40, it doesn't matter ;)

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Thanks for this.

Why NASA doesn't give the conversions in parentheses is beyond me. Surely they know that people around the world use another system, and that even in the USA, many people consulting the website have an interest in science and therefore know about the SI system.

(Or am I wrong on the latter ... are degF, inches, pounds, etc used in science teaching in the USA?)

In early Science teaching in the USA, say K-8 Fahrenheit is probably the focus. Starting in High school its more of a mix of F/C/K, and once at the college / university level it'll be pretty much exclusively C/K for science.

For a general consumption science article targeting an American audience it makes sense that Fahrenheit is used, because American's are used to it and its convenient for human temperatures. (More precision per degree, 0-100 is a common temperature range, mostly human comfortable).

Of course clearly including Celcius alongside Fahrenheit would make a lot of sense, I agree its strange that both were not included.

> targeting an American audience

What led you to believe this was targeting an American audience? Do you think kids in other countries don’t know about space, or aren’t interested?

I mean, NASA is an American government agency paid for with American tax dollars...
FWIW, Celsius is just as convenient for human temperatures (whether we're talking about the temperature of the human body or temperatures that humans can experience). The difference in resolution (about 2x good for F) doesn't really matter. Trust me, we rarely use decimals with C, except for when we measure body temperature (which is in a few C/F range anyway). Other than that it's just remembering the important values (freezing and boiling point of water, normal body temp, and maybe a few others that you can associate with how much dress you'll need if you go outside).

It's all about what you're used to, really.

I've switched to Celcius as an American since weather is mostly conveyed to me through the phone now-a-days. I've been using it for 2 years now and I am pretty well calibrated to California temperatures: 14C or lower, wear a jacket, 15-25C slightly chilly to pleasant, 25-35C is warm and hot.

It indeed is just about getting used to it. Precision of Farenheit actually gets in the way, usually we don't really care if it is 41F or 42F. It's the same. Wear a jacket.

I still can't get used to cm for measurement of everyday objects. Inches are just so easy for me.

In terms of weight/volume, I use ml/liters for fluids and g/kg for weight everywhere I can.

The conversion between Fahrenheit and Celsius is easy. You just take the numbers 9, 5, and 32 and put them in different combinations until you get the right formula, knowing that 0 = 32 and 100 = 212, and maybe that 37 = 98.6.
In comparison, Russia's (and world's) coldest permanently inhabitated town Oymyakon has a record of -71 Celsius.

It's cold, but survivable.

But your peepee shrinks to planck length
NASA using degree Fahrenheit in this article... there is no hope.
It's essentially a press release written for popular consumption in America. If it was a scientific paper, ok sure use K, but that isn't what you're reading.

Using units unfamiliar to the taxpayers supporting the mission seems counterproductive.

In fact it's cold as hell.
That ain’t no place to raise your kids.
While I enjoyed the article, I was very pleasantly surprised by how rapidly the page loaded - without pop ups, ads or newsletter nagging.