Ice Found On Mercury

[Broomstick]

I found this interesting:

On closest planet to the sun, NASA finds lots of ice
By Kenneth Chang
New York Times
Posted: 11/29/2012 12:01:00 AM CST
Updated: 11/29/2012 09:35:17 PM CST

Mercury is as cold as ice.

Indeed, Mercury, the closest planet to the sun, possesses a lot of ice -- 100 billion to 1 trillion tons -- scientists working with NASA's Messenger spacecraft reported Thursday, Nov. 29.

Sean Solomon, the principal investigator for Messenger, said there was enough ice there to encase Washington, D.C., in a frozen block 2 1/2 miles deep.

That is a counterintuitive discovery for a place that also ranks among the hottest in the solar system. At noon at the equator on Mercury, the temperature can hit 800 degrees Fahrenheit.

But near Mercury's poles, deep within craters where the sun never shines, temperatures dip to as cold as 370 degrees below zero.

"In these planetary bodies, there are hidden places, as it were, that can have interesting things going on," said David Lawrence, a senior scientist at the Johns Hopkins University Applied Physics Laboratory working on the Messenger mission.

The findings appear in a set of three papers published Thursday on the website of the journal Science. The ice could be an intriguing science target for a future robotic lander or even a resource for astronauts in the far future.

Planetary scientists had strong hints of the ice a couple of decades ago when telescopes bounced radio waves off Mercury and the reflections were surprisingly bright. But some researchers suggested the craters could be lined with silicate compounds or sulfur, which might also be highly reflective.

The Messenger
spacecraft, which swung into orbit around Mercury in March 2011 and has completed its primary mission, took a closer look by counting particles known as neutrons that are flying off the planet. High-energy cosmic rays break apart atoms, and the debris includes neutrons.

But when a speeding neutron hits a hydrogen atom, which is almost the same weight, it comes to almost a complete stop, just like in billiards when the cue ball transfers its momentum to another ball. Water molecules contain two hydrogen atoms, and thus when Messenger passed over ice-rich areas, the number of neutrons dropped.

The same technique was used to detect frozen water below the surface on Mars and within similar craters on the moon.

The neutron number would not have dropped if the bright surfaces were made of sulfur or silicates.

"Water ice is the only candidate we've got that fits all those observations," said Solomon, who is also director of Columbia's Lamont-Doherty Earth Observatory.

The ice is almost pure water, which indicates that it arrived within the past few tens of millions of years, possibly from a comet that smacked into Mercury. Solomon said several young craters on the surface of Mercury could be candidates for such an impact.

Not all of the icy regions were bright. In slightly warmer regions, where temperatures exceed minus 280, the ice was covered by a dark layer about half a foot thick. The scientists believe in these places the water ice vaporized, leaving behind other materials that had been trapped, including carbon-based molecules known as organics.

That could be similar to how water and the building blocks of life reached Earth billions of years ago.

The water could also be an intriguing resource for people. Between the scorched equator and the frozen poles, temperatures on Mercury can be temperate, especially a few feet below the surface, where the soil insulates against the temperature swings between day and night -- an ideal location to build a colony.

"People joke about it, but it's not so crazy, really," said David Paige, a professor of geology at UCLA who calculated the crater temperatures.

[Irbis]

But near Mercury's poles, deep within craters where the sun never shines, temperatures dip to as cold as 370 degrees below zero.

In slightly warmer regions, where temperatures exceed minus 280, the ice was covered by a dark layer about half a foot thick.

What.

And people are surprised when Martian probes crash due to stubborn usage of archaic measuring system...

[Sea Skimmer]

What do you mean what? Minus 280 degrees is warmer then minus 370 degrees, no matter what units you use.

[DireApostasy]

What do you mean what? Minus 280 degrees is warmer then minus 370 degrees, no matter what units you use.

Irbis appears to be referring to how those temperature measurements are in Farenheit, since unless I'm misremembering, absolute zero is -273 degrees C. He's also probably referring to that Mars Rover that ploughed into the planet at high speed because one part of the team was using kilometres, and the other team miles, so it ended up going waaaaaaay too fast when it should've been slowing for landing.

[Irbis]

What do you mean what? Minus 280 degrees is warmer then minus 370 degrees, no matter what units you use.

Enlighten me how exactly they didn't get Nobel prize for crushing half of laws/principles of physics as both quoted temperatures violate every single one relating to energy, entropy, thermodynamics, and half a dozen other fields. Well, unless they were not using one of two temperature measurement systems that are exclusively used in astronomy.

And I was referring to the most expensive canonball in history when another attempt to use units based on body parts and decrees of dead English king for astronomic measurements ended with epic fail.

[xthetenth]

And we're absolutely certain the NYT didn't convert the temperatures for its readership which is uncomfortable with scientific temperature membership?

[The Duchess of Zeon]

Yeah, I am strongly in favour of the NYT author being "convert xx celsius to xx fahrenheit" in google while writing the article.

[Sea Skimmer]

Of course they are using Fahrenheit, because they say Fahrenheit one sentence earlier. This is just about Irbis being retarded as ever. I was just giving him a chance to maybe act less stupid then normal, instead he seems to be ranting about how he doesn't know the New York Times is not an astronomy publication, or intended for anything but a general American audience. The best part being his complaint that only two units are allowed... which is already enough to cause the exact same problem Lockheed had anyway.

[Imperial528]

And I was referring to the most expensive canonball in history when another attempt to use units based on body parts and decrees of dead English king for astronomic measurements ended with epic fail.

Imperial units are fine for engineering purposes, so long as you remember to convert if a design or program originally in Imperial is then ported to a project using another system. The problem with the Mars Climate Orbiter was that one of the ground control computers had software that output the data in the wrong units. They could've used gcs instead of Imperial in the program and the result would have been little different. (Though in that case you would probably have the spacecraft shoot right past Mars instead of disintegrating in the atmosphere, as the dyne is smaller than the newton)

[PeZook]

Funnily enough, Apollo used all Imperial units and went just fine.

[Irbis]

Imperial units are fine for engineering purposes, so long as you remember to convert if a design or program originally in Imperial is then ported to a project using another system.

The first and foremost problem with Imperial units is that they add extra layer of opacity and opportunity for many more bugs when merely attempting to convert from one Imperial unit to another, never mind Imperial to metric, instead of not converting at all but merely formatting output as is the case with metric system. This alone disqualifies IU in any mission critical application, if only due to KISS principle, especially in modern flight software.

And yes, Apollo worked because everything was done by hand then and onboard electronics were about as complicated as pocket calculator - you could have checked everything, even if using IU meant a lot of pointlessly wasted manhours that could have been spent better.

Of course they are using Fahrenheit, because they say Fahrenheit one sentence earlier. This is just about Irbis being retarded as ever. I was just giving him a chance to maybe act less stupid then normal, instead he seems to be ranting about how he doesn't know the New York Times is not an astronomy publication, or intended for anything but a general American audience. The best part being his complaint that only two units are allowed... which is already enough to cause the exact same problem Lockheed had anyway.

You know who is retarded? It's someone defending something equally idiotic as measuring the cost of USS Nimitz in McDonalds doughnuts, as this would be unit 'intended for general American audience'. Especially if doughnut unit was used in newspaper intended for military officers.

Ok, I'll give you benefit of doubt and will assume you're as dumb as stereotypical American, then, as rest of the world has no problems reading temperature in Kelvins, despite our press being also intended for general public and us not using Kelvin scale. At worst, you will see quick explanation what the unit is or conversion in parenthesis. Though, people who read scientific articles usually do show interest in science in the first place, enough to know what the only standard scientific units are, and don't need even that dumbing down most of the time. If only because they paid attention in elementary school...

And gee, Kelvin and Celsius can be easily differentiated in a glance while testing up to extreme temperatures exceeding boiling point of iron, especially if you have any idea what the temperature is supposed to represent. Convincing your superior there is a problem with wrong scale being displayed would be trivial if we assume this replaced the problem NASA had then. Not only this, you don't even need to convert them, all you need is formatting display by adding 273.15 degrees when you need to see data in °C. I'll chalk your inability to see this or differentiate these to stereotypical American intelligence level, too

[Sea Skimmer]

I love how your response is 'but we can see the difference easily' after you just complained about confusion over a physically impossible temperature. Your idiocy is staggering

[Simon_Jester]

Imperial units are fine for engineering purposes, so long as you remember to convert if a design or program originally in Imperial is then ported to a project using another system.

The first and foremost problem with Imperial units is that they add extra layer of opacity and opportunity for many more bugs when merely attempting to convert from one Imperial unit to another, never mind Imperial to metric, instead of not converting at all but merely formatting output as is the case with metric system. This alone disqualifies IU in any mission critical application, if only due to KISS principle, especially in modern flight software.

Silly Irbis, don't you know that anyone too stupid to divide by 12 or add 273 has no right to an opinion?

More seriously... Why is the computer more effective when converting meters to centimeters than feet to inches? Computers use binary, not decimal; multiplying by twelve is not harder than multiplying by 100.

And yes, Apollo worked because everything was done by hand then and onboard electronics were about as complicated as pocket calculator - you could have checked everything, even if using IU meant a lot of pointlessly wasted manhours that could have been spent better.

Exactly how many man-hours were wasted in this way.

[xthetenth]

And yes, Apollo worked because everything was done by hand then and onboard electronics were about as complicated as pocket calculator - you could have checked everything, even if using IU meant a lot of pointlessly wasted manhours that could have been spent better.

Exactly how many man-hours were wasted in this way.

More importantly how many hours were used in this way that wouldn't have been used in testing the same exact code?

[Imperial528]

Imperial units are fine for engineering purposes, so long as you remember to convert if a design or program originally in Imperial is then ported to a project using another system.

The first and foremost problem with Imperial units is that they add extra layer of opacity and opportunity for many more bugs when merely attempting to convert from one Imperial unit to another, never mind Imperial to metric, instead of not converting at all but merely formatting output as is the case with metric system. This alone disqualifies IU in any mission critical application, if only due to KISS principle, especially in modern flight software.

As someone who uses both unit systems, I will tell you right away that I actually prefer Imperial to metric for design work. This is for two reasons, the first being that I still can't visualize a meter properly when working in a virtual space, the second is that (and this may scar you for life) I actually like the different conversions. When working in pure metric I often find myself swimming in zeroes (more than once literally when I have dropped papers with calculations on them), and when I get to complex calculations it can confuse me to no end. I also like that the foot can be evenly divided by 2, 3, 4, 5, 6, and 8 without a repeating decimal rearing its ugly head. Unlike metric, being base ten, which will encounter repeating decimals on 3 and 6 as well as 7 and 9. And I also like fractions, difficult as they can be.

Your later argument about keeping it simple works for having a consistent unit system throughout the project, as in, using only one system of units. But a computer can make the conversions between Imperial units just as easily, and by hand they aren't that hard either, even for normal people. Hell, I know people who can't understand metric prefixes because scientific notation is beyond their grasp, but they can pretty easily remember that there are 5280 feet in a mile and 12 inches in a foot.

[Napoleon the Clown]

The average American can't readily convert Imperial to metric because the average American didn't get a meaningful amount of time spent on metric, not because they "didn't pay attention." I know how to convert most measurements off-hand but I don't readily picture what 20 C feels like whereas 48 F tells me "it's a little chilly." Americans basically all grew up using SI, not metric. Expecting a product intended for American audiences, especially when the audience is composed almost entirely of laypersons, to use a format few will understand is about the same as trying to have someone who is ESL read deeply philosophical work in English and not their native tongue. It takes more effort to do it.

Now, if the scientists themselves were to publish the paper using SI you could complain about SI being used here. But I'm pretty sure the conversion was done for the benefit of the audience, much like is done when a country runs a story about how many (currency here)s were spent by the country that uses a different currency. Sure, people could just go look up exchange rates, allowing a US news agency to say that such and such storm caused 500 million pounds of damage. But most people won't, they'll look for a story that uses currency the reader understands.

To get upset that the article uses Imperial and not metric is... silly.

[PeZook]

And yes, Apollo worked because everything was done by hand then and onboard electronics were about as complicated as pocket calculator - you could have checked everything, even if using IU meant a lot of pointlessly wasted manhours that could have been spent better.

Representing the AGC as a calculator really gets on my nerves: it had as much PROCESSING POWER as a modern calculator, and obviously required only 1960s technology to make, but when you considered the complexity and difficulty of the project, its design and production process, it was nothing like making a pocket calculator. At all.

More importantly how many hours were used in this way that wouldn't have been used in testing the same exact code?

Modern flight software is going to have way more man hours dedicated to debugging anyways, because it uses ten or twenty times the amount of code that the AGC did, while the production process itself is outright trivial by comparison. The AGC had to have its innards physically rewired every if you decided to change the programming of the finished article. The man-hours wasted on implementing unit conversion would be utterly dwarfed by the act of reprogramming the computer

And as Simon pointed out, for a computer, multiplying by 12 is no harder than multiplying by 100. You can just as easily say that metric units introduce the possibility for order of magnitude errors if someone fucks up the code, and thus should not be used...

[xthetenth]

Irbis: fun idea. Degrees Kelvin are a more scientifically useful measurement of temperature than Celsius. Next time someone asks you the temperature in your lovely scientific wonderland, give it to them in Kelvin. Tell me whether they look confused.

Modern flight software is going to have way more man hours dedicated to debugging anyways, because it uses ten or twenty times the amount of code that the AGC did, while the production process itself is outright trivial by comparison. The AGC had to have its innards physically rewired every if you decided to change the programming of the finished article. The man-hours wasted on implementing unit conversion would be utterly dwarfed by the act of reprogramming the computer

What I was getting at (that this reinforces) is that this is going to get pored over with a fine-toothed comb because this is something that cannot go wrong. Every line of code is going to get inspected anyway, so checking the units is a relatively small addition to the overall test.

[amigocabal]

The average American can't readily convert Imperial to metric because the average American didn't get a meaningful amount of time spent on metric, not because they "didn't pay attention." I know how to convert most measurements off-hand but I don't readily picture what 20 C feels like whereas 48 F tells me "it's a little chilly." Americans basically all grew up using SI, not metric. Expecting a product intended for American audiences, especially when the audience is composed almost entirely of laypersons, to use a format few will understand is about the same as trying to have someone who is ESL read deeply philosophical work in English and not their native tongue. It takes more effort to do it.

Now, if the scientists themselves were to publish the paper using SI you could complain about SI being used here. But I'm pretty sure the conversion was done for the benefit of the audience, much like is done when a country runs a story about how many (currency here)s were spent by the country that uses a different currency. Sure, people could just go look up exchange rates, allowing a US news agency to say that such and such storm caused 500 million pounds of damage. But most people won't, they'll look for a story that uses currency the reader understands.

To get upset that the article uses Imperial and not metric is... silly.

Yeah.

The only reason we Americans even learn metric at all is because our major trading partners use metric, and as such, learning metric, as well as learning how to convert between metric and Imperial units, is useful.

I could, in theory, invent a new system of measurement (for example, basing the unit of length as a fraction of the height of the Statue of Liberty), but unless it gets wide spread use, nobody would bother learning how to use it. Measurements are one field where the bandwagon is not a fallacy.

This also explains why Celsius measurements are not used very often in America. A 3 meter pole loaded onto a ship in Yokohoma will still be three meters when it arrives in port in Seattle, so it is useful to know what a meter is, but its temperature will not remain constant. For us, Celsius has as much relevance as Rankine.