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via hardware verification with ACL2.

I hope this helps the LHC Experiment so it doesn't cause
a black hole to destroy THE UNIVERSE.

Yours In Physics,
Kilgore Trout

I thought Limbo was just the pleasant part of Hell where the City of Virtuous Pagans is?

What are the other new features of GRACE2 over GRACE?

The "drag-free" concept that GOCE is using has been popular at the GRACE Science Team Meetings. This would allow GRACE's altitude to be lowered from its current ~500km (starting) altitude to something more like 200km. Lowering the altitude increases the spatial resolution because from very far away the Earth's gravity field looks exactly like a point mass's. The closer to the surface the satellite gets, the more of the extra features are revealed.

A laser ranging system is also being considered, but we're having a great deal of trouble getting our noise floor (due to mis-modeled forces on the satellite and errors in modeling known sources of gravity fluctuations such as tides and atmospheric circulation) low enough so that we're actually limited by the reduced accuracy of the microwave system. Until then, it's hard to argue for a more expensive system that doesn't seem necessary.

I've seen interesting proposals for a more complicated orbit geometry. David Wiese proposed a "cartwheel" orbit where 2,3 or 4 GRACE satellites would revolve around each other as they orbit the planet. Sometimes the satellites would be at the same altitude, at other times they'd be right on top of each other. The laser ranging systems would be continually synced, so measurements of gravity variations could be made along radial directions instead of along the theta (or phi, depending on which spherical coordinate system you prefer) direction. These added degrees of freedom could help eliminate a strange, unexplained error source that we whimsically call "longitudinal striping" (Sean Swenson developed a smoothing algorithm that reduces it, but we still don't really know why it happens).

Aside from that, we're just trying to make sure that there IS a GRACE 2. Many of our long term measurements are limited by the short (~6 year) timespan of the data. GRACE is slowly falling out of the sky (I think it's projected to burn up in 2012 or so) and it's dangerously low on propellant. We need another mission like GRACE to extend the time series, and it's best to launch the second mission before the first one fails to cross-validate the time series from both satellite systems.

What are the other new features of GRACE2 over GRACE?

The "drag-free" concept that GOCE is using has been popular at the GRACE Science Team Meetings. This would allow GRACE's altitude to be lowered from its current ~500km (starting) altitude to something more like 200km. Lowering the altitude increases the spatial resolution because from very far away the Earth's gravity field looks exactly like a point mass's. The closer to the surface the satellite gets, the more of the extra features are revealed.

A laser ranging system is also being considered, but we're having a great deal of trouble getting our noise floor (due to mis-modeled forces on the satellite and errors in modeling known sources of gravity fluctuations such as tides and atmospheric circulation) low enough so that we're actually limited by the reduced accuracy of the microwave system. Until then, it's hard to argue for a more expensive system that doesn't seem necessary.

I've seen interesting proposals for a more complicated orbit geometry. David Wiese proposed a "cartwheel" orbit where 2,3 or 4 GRACE satellites would revolve around each other as they orbit the planet. Sometimes the satellites would be at the same altitude, at other times they'd be right on top of each other. The laser ranging systems would be continually synced, so measurements of gravity variations could be made along radial directions instead of along the theta (or phi, depending on which spherical coordinate system you prefer) direction. These added degrees of freedom could help eliminate a strange, unexplained error source that we whimsically call "longitudinal striping" (Sean Swenson developed a smoothing algorithm that reduces it, but we still don't really know why it happens).

Aside from that, we're just trying to make sure that there IS a GRACE 2. Many of our long term measurements are limited by the short (~6 year) timespan of the data. GRACE is slowly falling out of the sky (I think it's projected to burn up in 2012 or so) and it's dangerously low on propellant. We need another mission like GRACE to extend the time series, and it's best to launch the second mission before the first one fails to cross-validate the time series from both satellite systems.

http://www.utexas.edu/news/2009/02/16/spring_2009_enrollment/

Liberals are succeeding at disenfranchising whitey and guaranteeing equal outcomes for everyone instead of equal opportunities! Yay!!!

Because you can't compile a mathematical definition.

If you've read the works of E.W. Dijkstra (start with Cruelty), you'd understand that a programming language isn't much more than a formal system for expressing mathematical definitions. Perhaps Haskell or another purely functional language might fit your intuitive understanding of a "mathematical definition" better than a procedural language like C, C++, P*, or Java.

This has, of course, been muddied by the extremely popular usage of "I have limited bandwidth. I only get 20GB of download a month."

My university IT department uses "bandwidth" in this way. This is at The University of Texas, which has prestigious computer science and computer engineering faculties, I believe.

The IT department on campus puts caps on bandwidth usage, and if you go over each week, you have to more "bandwidth."

http://resnet.utexas.edu/support/more-bandwidth.html

If you have reached your bandwidth limit, you may purchase additional bandwidth in 1-gigabyte (GB) increments from the Public Network Store in TX Shop (up to three GB per week). Purchased bandwidth will first be used to make up the amount by which you exceed your allocation, and the remainder is available for you to use on the 1st-class service bracket until your reset day, when your account is reset to your full bandwidth allocation.

There, the residential network seems to be conflating the throughput and dictionary usages of the word.

...every economist that I've read says that ironically, that massive layoffs are the beginning of the end of an economic downturn, and that it appears as though things will be back into shape around the end of 2009 or the beginning of 2010, and none of their arguments are contingent upon a stimulus package. In fact, none mention it.

I don't know where you're getting your news, but most economists I've been reading (Krugman, Reich, Roubini, Galbraith, Taleb, etc.) say we're at the beginning, not the end, of a massive downturn. That the stimulus is not only necessary but nowhere near big enough to fill the demand gap created by this crisis. We need about 2 trillion in direct, massive government spending. We're getting only 800 billion (so far), of which a huge proportion is political garbage like tax cuts which are not very effective, AMT stuff which will not create jobs, etc.

Note that these are the same economists who long warned this crisis was coming. We ignore them at our peril.

"Now, therefore, I, Gerald R. Ford, President of the United States, pursuant to the pardon power conferred upon me by Article II, Section 2, of the Constitution, have granted and by these presents do grant a full, free, and absolute pardon unto Richard Nixon for all offenses against the United States which he, Richard Nixon, has committed or may have committed or taken part in during the period from July (January) 20, 1969 through August 9, 1974."
http://www.ford.utexas.edu/library/speeches/740060.htm

According to the DOJ http://www.usdoj.gov/pardon/pardon_instructions.htm, "a presidential pardon ... is granted in recognition of the applicant's acceptance of responsibility for the crime".

President Gerald Ford granted "a full, free, and absolute pardon unto Richard Nixon for all offenses against the United States." (http://www.ford.utexas.edu/library/speeches/740060.htm) which means that Nixon had to accept responsibility for his crime(s).

Impeachment proceedings (i.e. prosection) were started but various deal-making (including resigning the Presidency) delayed completion long enough for him to get pardoned for his crimes before any impeachment or prosection could complete.

When the criminal pleads out before the jury hands down a conviction it does not make the criminal not-guilty.

The DOJ's instructions for receiving a pardon may not be part of "a basic understanding", but its not very polite to insult someone when accusing them of a lapse you're busy committing yourself.

Prove that the simplest explanation is the truth? No. Prove that it's the most likely? Absolutely. Check out William H. Jefferys and James O. Berger, Sharpening Ockham's Razor On a Bayesian Strop, 1991 for a quick introduction.

The most sensible hypothesis is the simplest (if you want a mathematically precise version of that statement see, for example, http://quasar.as.utexas.edu/papers/ockham.pdf). I have not heard that any god is a simpler, more likely configuration of atoms (or whatever gods are made of) than nature. Nor have I heard that the Greek philosophers were the last word on biology or physics.

But that's not really relevant here. What's relevant is the difference between (1) admitting that you don't know something and don't yet have the technology that will permit the necessary experiments and (2) bullshitting a "logical requirement" and inferring something based on wishful thinking.

Well, why don't we look at the article and read some of these papers published on the vanity press?

It may be a rather well known fact, at least for all round educated mathematicians, that there are 17 and only 17 distinct types of wallpaper patterns in terms of their symmetry groups. Many of these patterns were known and used by the Arabs in Spain to decorate their palaces, for example the world famous Alhambra in Spain [9,10]. Less well known however is the fact that there are 5 Dirichlet domains corresponding to these 17 groups and that there are exactly 17 two and three Stein spaces with a total sum of dimensions found by the Author to be exactly equal to [14]:

5 0 +1 =(5 )(137 )+1 =685 +1 =686

Okay... The people in TFA have a lot more, but basically these papers appear to be gibberish. I hasten to mention that in spite of the odd name, there are 17 wallpaper groups, but the fact is that he comes up with all these occurances of numbers like 686 and appears to be claiming there's some kind of meaning behind it without specifying what, exactly, he's claiming.

It might help if everyone asked their school library to stop subscribing to this "journal" and perhaps review other journals by this same publisher to see if they are worth keeping. At a time when worthwhile journals are being cut, it's a shame that schools are still paying for this one.

Where's the article?

Second link in the summary:

http://golem.ph.utexas.edu/category/2008/11/the_case_of_m_s_el_naschie.html

Right here!

He cared deeply about the human dilemma and the rape of Earth.

He advocates killing 90% of the worlds population with the ebola virus. http://www.sas.org/tcs/weeklyIssues_2006/2006-04-07/feature1p/index.html

IIRC, it was more "considers it inevitable" rather than "advocates".

Right here!

He cared deeply about the human dilemma and the rape of Earth.

He advocates killing 90% of the worlds population with the ebola virus.
http://www.sas.org/tcs/weeklyIssues_2006/2006-04-07/feature1p/index.html

Heh sounds like someone else got a good read out of Dijkstra's essay as well.

Nice analogy for pointing out that one shouldnt be making analogies between material engineering and computing!

Peer-review isn't always what it's cracked up to be. Read about the Bogdanov controversy that erupted in my uni some years back that exposes some serious flaws in the peer-review process.

http://en.wikipedia.org/wiki/Bogdanov_Affair

Or read about the ongoing El Naschie affair:

http://golem.ph.utexas.edu/category/2008/11/the_case_of_m_s_el_naschie.html

This link is from 2001
http://www.utexas.edu/news/2001/05/17/nr_comet/
I just finished biochemistry and I am confused by the carbon-2 reference myself. I assume they are not talking about c 12 or C 13 isotopes, but I cannot tell what they are talking about, even after two articles with the same naming convention. Yes I agree 6 Protons and 6 Neutrons that weigh 2 AMUs would definitely be of alien origin. I assume they are saying it is a two carbon chain or three carbon chain. 1 2 3 4 Methyl Ethyl Propyl Butyl.

Notice that is about software, and starting at zero is considered optimal .

Edsger Dijkstra, the greatest computer scientist to never own a computer

Dijkstra did own a computer. He bought a Macintosh:

"Even after he succumbed to his UT colleagues' encouragement and acquired a Macintosh computer, he used it only for e-mail and for browsing the World Wide Web".

Source: U. Texas CS Department (In Memoriam): http://www.cs.utexas.edu/users/EWD/MemRes(USLtr).pdf

Edsger Dijkstra, the greatest computer scientist to never own a computer

I submit for consideration Alan Turing who may have designed the ACE and worked on the earliest computer (The Manchester Mark I) although never really owned it or any other computer. I think a lot of people identify him as not only a hero of World War II but also the father of all computers.

No. I have never seen Iridium flares. The only satellites I have seen are constantly moving dots of light with non-varying brightness. They look exactly like a star moving in a straight line at around the speed you would imagine an airplane to move at high altitude a great distance away. Here is a random link showing 75 different satellites that happened to be observed over a nine-day period.

Here is a video of a great Iridium flare, and here is a video of a not-quite-so-great Iridium flare.

HOL is said to be usable, but doesn't have the same opportunities for name abuse, though 2001 fans could come up with a whole bunch of new ideas. Isabelle, however, would provide such opportunities, if you were to combine it with the package that started this thread. ACL2 is the least abusable name of all, so is quite useless.

Perhaps I'm a bit of a purist, but if ECC Ram is actually self-correcting, I would worry about how/why it got corrupted in the first place. I find it much cheaper and easier to buy good quality non-ECC Ram instead.

ECC isn't just really meant to counter hardware memory errors. It's also meant to prevent single bit flip error events.

Cosmic rays and background radiation can cause single bit flip events. With increasing data densities, the likelyhood of a high-energy particle colliding with a memory cell increases. The other with increasing data densities is: the higher the density, the smaller the cell, and therefore the amount of energy required to flip a bit from 0 to 1 is reduced.

It's a similar problem to the RAID5 array issue (posted recently here on Slashdot), where the data densities are so high that you may enccounter a disk read error before your entire array rebuilds. Higher data densities are making once unheard-of errors possible.

And sometimes, you will immediately see the effects of a bit flip. Other times, the bit flip may remain undiagnosed for years, which can be more annoying (you may not have a backup from that long ago).

So, it's no surprise that ECC is becomming more popular, especially for workstations. As for myself, my current desktop doesn't have ECC, but I'm seriously considering the extra cost of ECC in my next computer.

Like many others here, it was logic that led me to CS. My degree is in philosophy, but my career is in software development. So maybe I'm a bit biased.

I can't really point to applications in the last 2.5 years, but I think you're overstating the case. I'm quite familiar with work done by people here (Nick Asher, mentioned on that page, was chair of UT's philosophy dept. for some time). Paul and Patricia Churchland have done a great deal to bring the philosophy of mind in line with contemporary scientific thought - which includes CS. Neural networks are now regularly discussed in undergraduate philosophy courses. In no other liberal arts major will you find students so familiar with the work of Kripke, Goedel, Turing, or Frege. Hell, I know CS majors who can't go toe-to-toe with a good philosophy major when it comes to theory.

And when you ask us to set aside "logic, predicate calculus and the philosophy of mathematics," you're asking us to ignore the foundation of the philosophy of language, a field of study that's enormously popular today and overlaps into linguistics, semantic modeling, etc.

That's not to mention whole subfields of metaphysics, such as ontology.

I'm not saying there's some "killer app" for philosophy here. But the fields are more closely bound than you make them seem.

A gent from Kenya that was all smiles and friendly as can be never had a problem. He always dressed nice and carried him self well. He always wondered what the African-American's were talking about.

Your examples don't prove your point, and they make you look a little clueless here.

If somebody dresses "nice", then that pretty much by definition means he dresses better than average. And what did he get for that? Not having a problem. Which is what the average white person gets without any dressing up at all.

Similarly, that white hoodlums getting treated like hoodlums doesn't prove that black people don't, on average, get treated a little worse than white people.

I'm not saying there is a giant difference in most places; these days you have to go to the ass end of nowhere to actually get dragged behind a truck. All I'm saying is that there is still a difference, and that difference affects people.

It's a truism that people notice problems easily, but rarely appreciate what they have. So that white males don't notice white male privilege is unsurprising. I'm sure I never would have noticed it except for a variety of experiences that made it painfully obvious to me.

The problem is not just with the return vehicle it is medical dealing with bone loss and radiation.
A simple to and from trip will take at best 2 to 2 1/2 years. Not include much time on the planet.
Based on studies from past studies for long term stays in space, primarily from the Soviet Union, and guesses it is thought that people would loose around 50% of the bone density, in certain bones, in 2 years, which would probably result in a high probability of serious health problems once they hit the earth gravity well. The bones could just collapse under standard weight and it would take years for them to be in a condition to walk under their own strength. For comparison osteoporosis is defined as a 25% bone loss and has a 175% increased chance of a bone fracture and a 325% increase for a hip fracture.

Don't be insulting. Isaac Asimov would never besmirch his name by writing for a lascivious, nudity-ridden rag like Playboy. The very idea is beyond contempt.

Asimov wrote The Union Club Mystery stories for Gallery.

Ahem.

(And yes, I'm aware that Asimov did, indeed, write for Playboy - and fittingly, darned near every other publication on the planet. Words to Asimov were like water to Niagara Falls.)

If you're worried about tuition costs, go to a (highly-ranked) state school rather than a private institution.

Of course a computer is going to be good at computing. That doesn't mean it's thinking.

Edsger Dijkstra said it quite well:

The question of whether Machines Can Think ... is about as relevant as the question of whether Submarines Can Swim

not scientifically groundless.
While more studies need to be done, there ahve been results indicating that games do help the elderly.

http://www.mwsearch.com/Games4elderly.html

http://www.thestar.com/News/article/163960

http://eric.ed.gov/ERICWebPortal/custom/portlets/recordDetails/detailmini.jsp?_nfpb=true&_&ERICExtSearch_SearchValue_0=EJ506062&ERICExtSearch_SearchType_0=no&accno=EJ506062

http://www.nur.utexas.edu/fachome/gmcdougall/Documents/DallasMorningNews.htm

http://www.ncbi.nlm.nih.gov/pubmed/18275322?ordinalpos=30&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

As always /. brings us old news: The n-category cafe carried a lively discussion of this business back in December. The response from the small sampling of mathematicians represented there was highly skeptical at best. Now who knows whether or not this program will be good for DARPA in the long run. However, there should be no doubt in anybody's mind that the proposer of these problems is no David Hilbert...

I write massively parallel scientific code that runs on these supercomputers for a living... and this is what I've been preaching all along.

The thing about RoadRunner and others (such as Red Storm at Sandia) is that they are special pieces of hardware that run highly specialized operating systems. I can say from experience that these are an _enormous_ pain in the ass to code for... and reaching anything near the theoretical computing limit on these machines with real world engineering applications is essentially impossible... not too mention all of the extra time it costs you in just getting your application to compile on the machine and debug it...

My "day-to-day" supercomputer is a 2048 processor machine made up of generic Intel cores all running a slightly modified version of Suse Linux. This is a great machine for development _and_ for execution. My users have no trouble using my software and the machine... because it's just Linux.

When looking at a supercomputer I always think in terms of utility... not in terms of Flops. It's for this reason that I think the guys down at the Texas Advanced Computing Center got it right when they built Ranger ( http://www.tacc.utexas.edu/resources/hpcsystems/#constellation ). It's about a half a petaflop... but guess what? It runs Linux! And is actually made up of a bunch of Opteron cores... the machine itself is also a huge, awesome looking beast (I've been inside it... the 2 huge Infiniband switches are really something to see). I haven't used it myself (yet), but I have friends working at TACC and everyone really likes the machine a lot. It definitely strikes that chord between ultra-powerful and ultra-useful.

Friedmud

Not quite open source, but publicly available for several years:

Tex's French Grammar

I'm confused- I thought mirror arrays were far superior at least in part because they don't have sagging problems and can correct on the fly for atmospheric disturbances by actuating the segments of the mirror. It certainly is a hell of a lot cheaper; U Texas did it for one third the cost of this thing, and theirs is almost a meter larger in "effective" diameter.

In fact, there are 7 or 8 telescopes larger than this, and eleven if you widen it to "larger or equal to".

Obviously, they wouldn't have done something like this if it was inferior, unless this was just for PR/bragging rights. So, why? Is the image quality inferior?

I'm not sure why your comment is a reply to mine, since it doesn't respond to any of the points I made. But what the heck, may as well.

... it seems the point of the article is that to get this fancy fontness (great, even more "sizzle" on the Web) you're presently going to have to get down with some MSFT DRM.

Well, no. That wasn't the point of the article at all. Actually, there were so many links in the submitted summary that I'm not actually sure which one was supposed to BE "the article". But the issue runs something like this:

In the '90s Microsoft added downloadable font support to Internet Explorer. Nobody really used it, because it had crappy DRM, it was hard to use, it only worked in IE, and the fonts generally were rendered badly.

Fast forward ten years.

Last March when Safari 3.1 came out, it had support for proper non-DRMed font files. It supports plain old TrueType fonts, and also OpenType fonts (.ttf and .otf, respectively). If you happen to be using Safari, you can look at a demo. In general this made people happy (though not everyone, even among the people who don't live in mortal fear of anything more outre than Verdana).

Hakon Wium Lie, the CTO for Opera, has been agitating for this kind of support for years, and promptly announced that Opera will be supporting that in the near future. There's a link for that in the article above. Shortly Firefox got on board as well -- support for downloadable fonts is scheduled to be released in Firefox 3.1.

After years of waiting, it looks as though web designers are finally, FINALLY going to have the ability to use any font they want, not just the nine fonts from Microsoft's "Web Core Fonts" project. Not everyone thinks that's a good idea, particularly those who tremble at the thought of such power being put in the hands of crappy web designers. And I'll happily admit that there are lots of crappy web designers. But downloadable fonts appear to be on the verge of becoming a reality even so.

The DRM angle comes in because Microsoft has begun trying to get their crappy DRMed format adopted as a W3C standard. Part of their argument is that font foundries won't accept a non-DRM solution, and so Microsoft's solution needs to be the standard everyone uses. Of course that's thoroughly undercut by the fact that Microsoft themselves allow font linking in Silverlight, without DRM, though they do restrict it to same-domain linking.

It's the same old song Microsoft has been singing for years -- Embrace, Extend, Extinguish.

Actually, they probably won't get to the "Extinguish" part with this particular gambit. It's more likely that they'll fail to get EOT standardized, but refuse to support non-DRMed TTF/OTF files, so that it will be harder to use downloadable fonts in a cross-browser way. That is, the designer will have to generate a new font file in EOT format, and then re-generate the same EOT font file for every different domain it's needed on, and finally added a separate IE-only style sheet.

Most sites with modern CSS-based designs already have IE-only style sheets using conditional comments, so adding one more chunk of code there isn't a large resource drain if you're not using multiple domains. But it would be much nicer if they would just support non-DRMed font files that would work wherever. Fat chance of that, though.

You don't need to be a print designer to want more fonts. The list of "safe" fonts that can be expected to work reliably in most web browsers includes:

Arial
Arial Black
Comic Sans MS
Courier New
Georgia
Impact
Times New Roman
Trebuchet MS
Verdana

That's it. NINE fonts for BILLIONS of web sites.

I'm not a print designer. But I make lots of web pages, and damn it, nine fonts is not enough. Typography is the single most powerful and versatile design tool in existence. You can use it to convey emotion, to highlight important bits of a page, to subtly improve reading comprehensibility, and on and on.

Not to mention the specialty uses. Have you ever tried to transliterate Egyptian hieroglyphs on the web? I have, and I had to go the sIFR route to represent characters which are just not available, such as the character shaped like a 3 representing a palatal A sound.

And then there's stuff like medieval transcriptions. How can I post a good transcription of a Middle English romance without the characters thorn, eth, yogh, and wynn? Some of those are available in standard fonts, especially thorn and eth, but yogh and wynn are a lot harder to come by. You can get them using Junicode, but only if your visitor happens to have that particular font installed, which 99.99999% of people do not. sIFR isn't really a solution in that case, because you only need four damn characters, repeated at intervals throughout a fairly lengthy text.

But hey, 640K should be enough for anyone!

Why not go to the extreme of magnification by gravitational lensing: use the Sun as a lens. Perhaps that degree of magnification would let one measure the atmospheric spectra of exoplanets directly.

Edsger W. Dijkstra nailed it long ago with his assertion that a line of code is a liability, not an asset. (paraphrased from the original essay)

Gates has also been quoted as saying, "There's only really one metric to me for future software development, which is - do you write less code to get the same thing done?"

This is probably the only thing Gates and I will ever agree upon.

I recommend SafeBoot. It is extensively deployed on all laptops in my client's company and it works great.

Frequency (higher = more dangerous), wattage and distance are the generally accepted determining factors for safety.

The signal strength declines on a logarithmic basis as distance from the source increases, so having the transmitter right against your skull ensures a good soaking in near ~800mhz RF but it's unlikely to do anything to the guy sitting next to you in the bus.

Many people work around higher frequency or higher powered RF without problems, I myself operate a ham radio station and keep things well within safety limits the majority of the time, but I would never expose myself to UHF frequencies even at 1/4 watt at such a close range.

Calculate it yourself, 800mhz 0.25 watts:
http://n5xu.ece.utexas.edu/rfsafety/

Evidently by FCC standards there could be a problem.

Dump Faux News. Change the networks' news divisions back to what they were - investigative agencies with journalists (fancy word for a person who went to college and learned how to research and write about the news - few exist in captivity and fewer still are seen on TV) placed in "bureaus" around the globe.

Avoid "imbedding" journalists (actually, no Journalist would put up with being "imbedded" - but six-figure salary Reporters are not so concerned with facts - just their pay) and while we are at it - dump 100% of the commentary - left, right and center. That's what EDITORIAL PAGES are for.

Anybody who wants to know what one type of Journalism looked like - the First Person Interview - need only check out this University of Texas archive from the late 1950's: http://www.hrc.utexas.edu/collections/film/holdings/wallace/

I had several comp sci professors with excellent handwriting. It's no coincidence they were trained by Dijkstra though.

Dear Moraelin,

If you want to do science, you have to use numbers properly.

You can put some numbers into the Stefan-Boltzmann law (this guy does the same thing), and if the Sun's radiation was all that was keeping the Earth warm, the average temperature would be 278 degrees Kelvin, or 5 degrees Celsius. In fact, the average temperature of Earth is closer to 15 degrees Celsius.

Why the discrepancy? The atmosphere traps heat, allowing the sun's visible light to penetrate to the ground, but preventing much of the infrared light form escaping. This is referred to as the "greenhouse effect". This is roughly why almost all scientists agree that changes to the atmosphere (such as volcanic eruptions or human emissions of carbon dioxide and methane) can change the Earth's temperature.

Could the Sun be getting brighter, thus explaining global warming? Interestingly, in 28 years of monitoring from space-based observatories, the solar irradiance has only varied in amplitude by about 0.2% (that's 0.002). That represents changes in the brightness of the Sun caused by the 11 year solar cycle. There is no evidence that the solar irradiance has increased (e.g., Frohlich & Lean 2004, Astronomy & Astrophysics Review, 12, 273; sorry I can't easily find something freely available outside of a university library). By your estimate, we require about a 1.2% increase in the Sun's intensity to account for global warming. There is no evidence the Sun could be the main cause of global warming.

Incidentally, Jupiter is not getting warmer. A large storm is redistributing heat in the atmosphere, which is very different (I'd say the science media interpreted that one wrong). The Mars data is controversial, because it covers a short time span, and was measured with two different instruments. The measurements on Earth are more reliable.

Please spend some quiet time in the Chapel of Science, considering these facts.

--Endstar

If you want to do science, you have to use numbers properly.

I've put some numbers into the Stefan-Boltzmann law (see also http://farside.ph.utexas.edu/teaching/sm1/lectures/node85.html), and if the Sun's radiation was all that was keeping the Earth warm, the average temperature would be 278 degrees Kelvin, or 5 degrees Celsius. In fact, the average temperature of Earth is closer to 15 degrees Celsius (see "terrestrial atmosphere" on http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html).

Why the discrepancy? The atmosphere traps heat, allowing the Sun's visible light to penetrate to the ground, but preventing much of the infrared light form escaping. This is referred to as the "greenhouse effect". This is roughly why almost all scientists agree that changes to the atmosphere (such as volcanic eruptions or human emissions of carbon dioxide and methane) can change the Earth's temperature.

Could the Sun be getting brighter, thus explaining global warming? Interestingly, in 28 years of monitoring from space-based observatories, the solar irradiance has only varied in amplitude by ~0.2% (thats 0.002; http://data.giss.nasa.gov/gistemp/2007/). The only long-term trends in the brightness of the Sun are those of the 11 year solar cycle. By your estimate, we require a ~1.2% increase in the Sun's intensity to account for global warming. There is no evidence the Sun has brightened that much, even if we try to apply recent measurements to data taken over the last few centuries (e.g., Frohlich & Lean 2004, Astronomy & Astrophysics Review, 12, 273; sorry I can't easily find something freely available outside of a university library).

You don't have to trust me --- you can examine all this yourself.

--Endstar

That's bullshit because using your screwy logic, the Speaker of the House would have to have the same qualifications.

http://www.lwvnj.org/guide/pres.shtml

http://www.lbjlib.utexas.edu/Johnson/lbjforkids/usgov.shtm

Dont suppose anybody could recomend a good sweedish -> english translator, for the few that are in sweedish?