You only have to look at the balanced chemical equation to see (which I got wrong, also not a chemist, and you're right about the bicarbonate being soluble!)

CaCO3 + H2O + CO2 = Ca(HCO3)2

This will certainly reduce the acidity of the water, increasing the pH, because carbon dioxide is being removed from the water and is in equilibrium with the carbonic acid ions.

CO2 + H2O = HCO3- + H+

There is a reason, however, that I know just from a thought experiment that this cannot be a positive feedback loop. If it were a positive feed back loop and calcium carbonate reacted with carbon dioxide in the water to increase the acidity of the water, then I could take some limestone, throw it into some water, and over time the limestone would totally dissolve and leave me with a cup of very strong acid. In other words, if this were the case, calcium carbonate in normal water would be unstable. You only have to look at some old quarries to see that this is not the case!

Whoops. That was supposed to be:

Calcium Carbonate + Carbon Dioxide < - > Calcium Bicarbonate

HTML!

It's actually not a positive feedback loop.

Calcium Carbonate + Carbon Dioxide Calcium Bicarbonate

So, calcium carbonate does *not* react with carbon dioxide to produce calcium bicarbonate and another carbon dioxide. That would violate conservation of mass. The reaction between calcium carbonate and carbon dioxide produces calcium bicarbonate which should precipitate out and increase the pH of the water to more neutral levels!

So I wondered just how much methane 2 mg/m^2/day is, and here's the breakdown:

2 mg/m^2/day times the area of the Arctic ocean (13,986,000 km^2) is 27,972,000 kg/day, or about 10.2 Tg/year.

10.2 Tg/year can be compared on this chart to other sources. This is not an insignificant amount, but is an order of magnitude less than just the contribution from farm animals.

I'm not a climate scientist, and can't say what this may or may not mean for AGW, but it puts the size of the emission into perspective.

Yes, you are technically correct, but that's not how anybody actually does the calculation. The "correct" way to model the sun would in fact be to do some ray tracing from every point on the sun--but that's ridiculous. Nobody is going to notice the 9mm on the edge of the shadow to appreciate your calculation in the first place, and even if they did the same effect could be achieved more efficiently by just softening the edges a bit using some graphics algorithm.

Similarly, it's just ridiculously expensive to treat the sun as a point at a huge distance, subtract the vector from the vector to a point on your model, then project along that vector onto whatever lies behind the model. It's slow and inefficient.

Instead, we just choose a vector for the incident sunlight and do a projection along that vector onto what lies behind the object. This is fast and efficient and how computer graphics are actually done in order to make your game run at reasonable FPS!

So, in an Optics class, both myself and my professor would both be wrong and you would be right. In a computer graphics class, the sun is most definitely a plane light source.

I wish I could say that I didn't still bite my tongue. I was at the ACM World Finals and have worked at several start-ups where code or an architecture was handed to me. In the past, when I've voiced concerns about serious flaws (such as: "I don't know what this totally undocumented and comment-free module for a critical medical device is supposed to do, but it's never done what you think it does since the first line is a type mismatch") to supervisors, I've been literally screamed at.

I thought that was over when I finished my PhD: that an advanced degree meant that my concerns would be taken seriously. Last week I asked for a task that it was thought could not be completed by a deadline because I felt that it would make the company look bad if it wasn't. I went and talked to several experienced engineers and came up with an elegant solution, and when I showed it to my supervisor he went flying off the handle because "I made a major change to the architecture without consulting him." In fact, what I'd done was changed a binary large object that was being passed around between some functions into a first-class object in the language for improved compatibility. I even showed him a demo where a malicious BLOB allows an attacker to compromise the system with four lines of code. He was certain that such an attack would never be implemented.

The project was completed on schedule, but unsurprisingly to any experienced software engineer exhibits random behavior when the binary large object is passed between machines in the cloud and would be very easy to exploit should anyone ever discover what's happening.

I can only conclude that everything is the same everywhere, no matter what. I'm actually going to a conference next weekend where I hope to make some connections that lead to me being the one in charge, but will certainly never bother to question anyone's authority here again.

Not quite the same, but I've seen college exams where the professor had it wrong, marked me wrong, and would not fix the mistake.

One professor (computer graphics exam) thought the Sun behaved like a point light source on Earth. It does not, it behaves like a plane light source because it is much larger than the Earth and the light arriving from the sun is for all computer graphics purposes arriving with the same vector direction. He would have none of it.

The other was on a quantum information exam, with a question about quantum encryption. Essentially a probability question involving a classical channel and a quantum channel. If he had been correct, then you would have been able to transmit information faster than the speed of light using quantum entanglement. You cannot, and instead you require the extra piece of information from the classical channel.

I've even had college profs knock me down a letter grade out of spite. This happened to me in two CS courses, one where I finished all of his weekly projects on the first day and aced his exams by reverse-engineering the code instead of memorizing what he wanted us to do. In the other, the prof was teaching an object-oriented programming class and couldn't figure out object polymorphism, so I offered to teach it for him because he said he was just going to skip that part of the course. I did a great job, but he didn't like being made to look like the amateur he was.

The grades don't bother me so much as the majority of a class walking out and having a misconception about the world around them or missing out on one of the most critical components of a subject. People pay good money for education and will go out and do important things that are relevant to anyone with what they learn, and that is absolutely important to me. That said, I learned long ago that most adults are actually just children that were given a measure of authority. While I can definitely sympathize with your situation, the approach I take now is never to touch anyone else's claim to authority.

Well, then I have just the thing to keep the ants away from my next picnic. Behold, the golden orb weaver picnic blanket!

http://www.wired.com/wiredscience/2009/09/spider-silk/

I can see how in some cases the computer would do a better job than a professor. In particular, ones that could not care less about teaching. I'm in Physics, and in one grad course there was an essay on an exam that I got a zero on. When I looked at the solutions, it appeared that the essay on the key was actually my essay with a few slight modifications. Two sentences of the short paragraph were my words exactly. When I brought this to the professor (who was also my advisor), he (a) couldn't remember my name (b) wouldn't even look at the exam (c) wouldn't discuss the answer and deferred everything to his grader, who was another grad student. The grader had better things to do and just handed my exam back to me and said, "that's what you deserve." This same professor, it should be said, makes psychotic Wikipedia self-edits about how his work "reconciles quantum mechanics with the Christian faith", rarely talks to other groups about his research (once one of his students came to me to ask a question about a problem he'd been working on for months--within minutes I identified it as being identical to a well-known NP-hard problem), and frequently "dumps" RAs he doesn't like by simply ending all communication with them.

My point is, the professors and TAs that grade unfairly don't do so because they can't. They do because they don't care. When I graded essays, I had a list of things I wanted to see in a correct answer and how many points they were worth, and a list of things that I would always take off points for. Every essay had a column of numbers next to it and a copy of my rubric so that any student could see exactly what they got points for and what they may have been penalized for. Out of classes of over a hundred students, I rarely received any complaints except for students who were on the border of failing and were desperate for one or two points. While sometimes grading essays felt like a simple application of a regular expression, searching for the gems of knowledge, equally as important was the logic that led to that conclusion. Correct answers obtained through incorrect application of concepts weren't worth any points at all, and it would be difficult for a program to match that with any regular expression.

I guess experience with bad professors did teach me one thing--despite having no passion for teaching myself, I would always treat my students like people and do my best to ensure that they got the best education possible for their tuition.

Wow. That's a remarkably cynical way of looking at things. There are plenty of occasions involving beer and a backyard that people broadcast on their favorite social network without much thought. I'm not claiming to be extremely popular nor particularly important to more than a couple dozen people, but it doesn't mean I can't have fun dancing or watching a campy zombie movie or playing a game of football with people I've met a few times, and it's just those things that being disconnected from social networking makes you miss out on.

There was an article on Slashdot a while ago about just that. Namely, that people could handle a relatively small number of close friends, and that social networking makes it very easy to keep in touch with a much larger group of people. Nonetheless, it has no effect on the number of people you can actually be meaningfully close with. So, we're not missing out on any of that.

As someone who never had a MySpace or FaceBook account, I'll be the first to say that I should have.

Back in college when MySpace was huge, I was constantly pestered by friends for my "MySpace", so that they could friend me. My canned response was, "I don't use MySpace, but if you want to find me you can just type my name into Google and my professional website is the first result." Well, guess who didn't get invited to the cool parties because the invite went out over MySpace? It still happens today with friends who use Facebook to send out invitations. You can tell people to use your e-mail, text you, or call you, but it's just not something that people think to do anymore. Facebook has become the preferred means of communication. I've even had a relationship fail out of the gate because the girl preferred Facebook flirting and I refused to indulge her. Just last week I got a call on my office phone from some friends from long ago who'd been looking for me. Since I wasn't on Facebook, it literally didn't occur to them that they could try entering my name in Google and find my contact information at the first result. Instead, by some circuitous route they managed to find a phone number I didn't even know--my office phone--since I just use my cell phone!

So, here's the moral of the story. To the masses, Facebook is the new phone book, post office and phone. If your address and number is unlisted, you may as well be living in a shack in the vast wilderness, because unless they're exceptionally close to you then your friends aren't going to find you, aren't going to contact you, and might even find it easier not to be your friend at all.

Somehow, I still decline to use Facebook. I'd rather go through my list of contacts on a rotating basis and send them a text to let them know that I still care. It is kind of funny to meet friends of my girlfriend and have them say, "Oh, you're that guy that's not on Facebook!"

So, maybe not being on Facebook makes me more memorable after all.

What would the impact have been on Earth if this had been pointing directly towards us? Would it have been on the scale of the Carrington event?

How many times have you been in this situation: many of your co-workers and friends have gone to see a movie and everyone seems to be chattering about it. You find yourself left out of lunch discussion or not getting jokes because your missed it. The problem is, the movie just doesn't sound interesting to you, or you don't have time, or you're waiting for the DVD release. Now replace "movie" with "video game" or "book" or maybe even "technical paper outside your area of expertise."

Spoilers in Wikipedia allow me to be "in" on every piece of pop culture that I don't particularly care about without commitment of time and money. If I decide I want to see the whole picture, I'll check it out. Usually, though, all you need to know are the bullet points!