by Kim Krisberg

When it comes to nonviolent drug offenses, systems that favor treatment over incarceration not only produce better health outcomes, they save money, too. It's yet another example of how investing in public health and prevention yields valuable returns on investment.

In a new study published in the June issue of the _American Journal of Public Health _(AJPH), researchers found that California's Substance Abuse and Crime Prevention Act, which diverts nonviolent drug offenders from the correctional system and into treatment, saved a little more than $2,300 per offender over a 30-month post-conviction period. In fact, researchers estimated more than $97 million in savings for the 42,000 offenders affected during the first year of the law's implementation. And even though the law resulted in spending more on treatment, health care services and community service supervision, bypassing incarceration still yielded overall savings, said study co-author M. Douglas Anglin, founding director of the UCLA Drug Abuse Research Center and associate director of the university's Integrated Substance Abuse Programs.

"In the long run, we're still saving money because we're not paying to incarcerate people," Anglin told me.

According to a 2009 report from California's Legislative Analyst's Office, incarcerating a single offender costs California approximately $49,000 per year.

California's Substance Abuse and Crime Prevention Act was enacted in 2000 as a result of a voter-approved initiative known as Proposition 36. The system change means nonviolent drug offenders who meet the law's criteria can be sentenced to probation with substance use disorder treatment instead of imprisonment or probation without treatment. The law gives offenders up to three chances to re-enter treatment without incarceration regardless of initial violations. Study authors Anglin, Bohdan Nosyk, Adi Jaffe, Darren Urada and Elizabeth Evans wrote that the law became a "statewide policy that changed the course of criminal justice processing" for all the individuals and sectors involved.

"The law represented a sea change," Evan told me. "It represented taking a real public health approach to substance abuse offenders in the state."

The AJPH study noted that in 2002, national estimates put the societal cost of substance abuse disorders at $180.9 billion, with the largest and fastest-growing contributors being criminal justice activities. In terms of public investments in substance use disorder activities, federal decision-makers in 2011 budgeted $7.6 billion for domestic law enforcement, but only $1.7 billion for prevention programs and $3.9 billion for treatment services. S__tudy authors wrote:

Public policies regarding criminal justice interventions with drug-using offenders have largely been driven by the acknowledged association between drug use and crime. The research literature has consistently reported that (substance use disorders) intensify rates of criminal activity, especially among dependent individuals. The importance of treating offenders with a (substance use disorder) is further illustrated by the fact that both severity of drug use and recidivism rates decline during and after treatment. Consequently, a reduction or cessation of drug use has been targeted as a direct method of reducing drug-related crime and enforcement and as an indirect method of reducing other adverse social consequences associated with drug use.

To examine the impact of California's treatment diversion law, the researchers compared two different groups: one that met the law's eligibility criteria in the years before the law was enacted (this was the control group) and another made up of eligible offenders convicted within the first year of the law's implementation. The study found that treatment participation was "substantially" greater among the post-implementation group than among the control group. Researchers also found greater incremental costs savings among black and Hispanic offenders due to related disparities in conviction and incarceration rates. The study concluded that diversion from incarceration to treatment should result in long-term savings.

Evans, a project director at UCLA Integrated Substance Abuse Programs, noted that the strength of California's diversion program really stemmed from its collaborative nature and having leadership from both the criminal justice and treatment communities working together.

"It was a big step toward acknowledging substance abuse as a health issue," she said.

The study's findings also suggest that "policy concerns regarding the welfare and rehabilitation of drug users should be seen as aligned with rather than running counter to the notion of fiscal responsibility and public safety concerns," the authors wrote. The fiscal findings are especially important considering California's current budget shortfalls, Anglin said. He noted that in 2009 state lawmakers eliminated funding for the law, kicking the financial burden down to the county level.

"These findings can help policymakers when they're trying to decide if a program like this is worth our taxpayer dollars," Evans said.

To access the full study, click here.

_Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for more than a decade.___

_Over the next 10 years, what research done on bodies within our Solar System (measurements and theory) will be most important for informing our search for life beyond the Earth?_

This is the current topic posed as the Single Question on the Future of Astrobiology at the ongoing NASA Astrobiology Institute Roadmap online exercise.

If you want to opine, The Forum is Open

The threshold of 400 carbon dioxide molecules per million molecules of Earth's atmosphere is an arbitrary but still significant milestone, reflecting a near 50% increase in the concentration of the greenhouse gas since humanity first started burning fossil fuels for industry. Sure, the Earth has experienced hotter chemistry before, but Peter Gleick says it all the in the title of his post: _The Last Time Atmospheric CO2 was at 400 parts per million Humans Didn’t Exist_. The Arctic was also free of ice, and CO₂ levels were changing 1000 times slower than they are today. Not that we can't survive and even thrive in the midst of an economy that daily poisons and deadens the Earth, but it will be a much uglier place we have paid for.

Recent reconfiguration of federal funding for STEM education has resulted in important programs at the NIH losing their funding. Below is information on Health and Biomedical Science Education Programs Aimed at Grades K–12 at the National Institutes of Health (NIH).

_________________________________

In the proposed FY 2014 budget, President Obama has set a policy that all STEM education funding be consolidated into three institutions, the NSF for graduate and undergraduate training, the Dept. of Education for K-12 STEM and the Smithsonian for informal education. Justification for this policy was improved efficiency and reduction of duplication of efforts, despite the government’s Committee on STEM Education (CoSTEM) Dec. 2011 report, Federal science, technology, engineering, and mathematics (stem) education portfolio, conclusion that “examination of the inventory data indicates very little overlap and no duplication among Federal STEM education investments.”

This policy is problematic because it dictates that NIH cease all STEM education programs, which includes the Science Educator Partnership Awards (SEPA) that fund BrainU (that is a specific program that is losing its funding). NASA and NOAA have also been prevented from continuing their STEM education efforts. These agencies have already begun policy implementation as Executive branch employees execute presidential policy. All NIH health education programs will disappear officially Oct. 1, 2013 unless we mobilize Congressional action to reinstate funding for SEPA. A full description of this problem can be found at http://nwabr.wordpress.com/2013/05/01/nih-science-education-programs-at-risk/.

This is problematic because a sub-mission of the NIH is to disseminate health information. This policy decision means that NIH will lose the ability to share health science educational materials for K-12 audiences. For scientists like myself who translate health information knowledge directly to teachers and indirectly to their students, this is a major setback. This policy sends the message that my colleagues and I are not supposed to be communicating with you as teachers.

Here’s what you need to do to raise your voice in support of SEPA

Contact your US Congressional Representatives and Senators. Below is a draft letter being circulated to all SEPA programs and participants, but you may find this letter a good template for making a more generalized show of support even if you are not a SEPA person. It only takes a few minutes to personalize this letter (1- 2 sentences is enough) and paste it into the contact your congress websites (see below). This is especially important for those of you in the south Metro and near SE MN who live in Minnesota’s 2nd District – U.S. Congressman John Kline’s district – as he is chairman of the House Education and Workforce Committee.

Our “ask” in these letters is that the funding for NIH health science K-12 education programs (SEPA) be reinstated.

We view neuroscience as part of health education since our message has been – and continues to be – that teaching learners about how their brains change through learning will improve their prospects and motivation to learn in all formal education settings AND in life as they move forward.

Please go to the websites for your congressional representatives and upload this letter with your personal touches to this campaign to save the NIH Science Education Partnership Award (SEPA) program from which BrainU is funded.

___________________ MORE INFORMATION:

Health and biomedical sciences for grades K-12 are critical components of STEM education that help to ensure the nation’s capability to prevent disease and improve health. The proposed 2014 STEM education consolidation plan, however, eliminates K-12 health and biomedical science education from its traditional place in the portfolio of the National Institutes of Health (NIH), and, by default, from the national STEM education agenda. No other federal agency supports programs comparable to those that would be lost.

More than 65 NIH-funded, K-12 health and biomedical science education projects currently operate in 40 states. These include “in-person” programs for more than 82,500 K-12 students and 5,750 K-12 teachers each year, and online programs that reach more than 20 million K-12 students and educators annually. NIH-funded exhibitions at some of the nation’s largest museums and science centers reach millions more students, teachers and families. With emphasis on engaging underserved populations, K-12 educational initiatives supported by NIH create thoroughly evaluated, science-rich interactive exhibits, curriculum materials, teacher professional development programs, student and teacher research experiences, and out-of-school learning opportunities.

Ongoing NIH-funded K-12 educational programs benefit the nation in the following ways.

* Improve preparation for, and access to careers in medicine, healthcare, biotechnology and biomedical research, with a focus on students from under-represented groups. * Address health disparities by increasing access to college and health professions careers for under-served students, who are more likely than their peers to practice in medically underserved areas. * Build public understanding and support of biomedical research and clinical trials through educational programs that emphasize the relationship between NIH discoveries and their translation into positive health outcomes * Encourage and facilitate involvement of biomedical research scientists in K-12 STEM education, and engage the resources of colleges, universities, medical schools and science museums in supporting K-12 STEM education. * Promote health literacy and better decision-making to address preventable health problems among America’s youth, reduce the burdens of chronic illnesses and infectious diseases, and enable consumers to make sense of genetic and other newly available health information. * Increase students’ interest in STEM topics through personally relevant examples from health and biomedicine that are aligned with recommendations of the Next Generation Science Standards. For more than two decades, NIH has invested in the development of human capital and a unique infrastructure that is meeting our nation’s K-12 health and biomedical science education needs. These investments have produced significant, demonstrable outcomes that would not have been possible otherwise. Current K-12 programs sponsored by NIH, including the Office of Science Education, employ rigorous, results-oriented and cost-effective approaches to tackle major national issues, as listed below.

Jobs: Healthcare and biomedical science are crucial elements of the economy. The US Department of Commerce estimates that healthcare accounts for $1.75 trillion in revenues and employs more than 14 million people (nine percent of the US workforce).

Provider Shortages: The nation faces an acute shortage of healthcare workers in all areas, and the problem is expected to grow. The American Association of Medical Colleges projects that there will be a shortage of more than 90,000 physicians—including 45,000 primary care physicians—by the end of the decade. About 55 million people already lack access to a physician.

Wellness and Disease Prevention: According to the Milken Institute, more than half of all Americans suffer from one or more chronic diseases, many of which are preventable. Healthcare spending is projected to reach almost 20% of the US gross domestic product by 2021. Racial and ethnic minorities suffer disproportionately from diseases such as cancer, diabetes and HIV/AIDS, but participate less frequently in programs that could help to reduce disparities.

Without K-12 health and biomedical science education initiatives, our nation will be unable to solve many of its most pressing workforce, economic and healthcare problems.

___________________________ Draft Letter

May 22, 2013

The Honorable

Dear :

I write to express my deep concern that the President’s proposed “consolidation” of Science, Technology, Engineering and Mathematics (STEM) education programs will eliminate the health-centered, precollege (K-12) education programs of the National Institutes of Health (NIH). For more than two decades, these programs have been the primary method by which NIH translates its basic and clinical discoveries to millions of children, families and teachers in the US.

As your constituent, I urge you to consider the implications of this change and to support retention of funding for K-12 health-related education within NIH, enabling the Institutes to continue this broad, critically important pathway to health literacy and jobs.

The programs slated for elimination have been a tremendous resource for K-12 students and teachers, especially those in minority and disadvantaged schools, for whom biomedical educational resources are very limited. Equally important, they are unique among all federal programs in enhancing health literacy and are crucial to NIH’s mission of promoting the health of our nation’s citizens. “In-person” programs engage more than 82,500 K-12 students and 5,750 K-12 teachers each year and online programs reach more than 20 million annually. Exhibitions at some of the nation’s largest museums and science centers reach millions more children, teachers and families

None of the agencies delegated to assume responsibility for STEM programs – National Science Foundation, Smithsonian Institution, and Department of Education – have a health education priority. The proposed action will result in the loss of critical, high-impact health-focused programs. Consolidation will greatly reduce the number of students entering health and biomedical research careers, threatening our nation’s overall health and health literacy.

NIH precollege programs enable biomedical researchers, health professionals and educators at universities, colleges, science museums and other organizations to connect with teachers, children and their families across the country. This outreach provides our communities with invaluable learning opportunities related to research, health, and wellness. Biomedical and health sciences are important areas of workforce development for the US economy in the 21st Century. Research demonstrates that NIH K-12 education programs are key to attracting students to these fields, thereby driving a robust biomedical economy and enhancing national health and wellness.

As a participant in the NIH SEPA BrainU program at the University of Minnesota, . Understanding how brains learn and process information is critical health information that learners will use throughout their lives. This message is one from the 80+ programs that will be abruptly ended by the consolidation policy that does not distinguish health literacy from general STEM education.

These essential programs must be retained so that the NIH can meet its unique mission of fostering our nation’s leadership in biomedical discovery and improving the health of its citizens. If this consolidation occurs, these effective programs and expertise will be lost.

Please feel free to contact me about this issue. I would be glad to provide additional insights into how this program has impacted my classroom so we may work together to save these important NIH programs.

Sincerely,

your name

I've never been able to figure it out. Antivaccine zealots seem to have an intense love of Nazi analogies and comparing those supporting science-based medicine to Nazis. While from a strictly nasty point of view, I can sort of understand the utility of such analogies to demonize one's opponents. After all, to political extremists of nearly all stripes (excluding actual real neo-Nazis, of course) Adolf Hitler is the gift that keeps on giving. Antiwar activists liked to try to tar George W. Bush with the Hitler appellation, and, now that Barack Obama is in power, right wing Tea Party types have an even greater tendency to try to paint (or to slime) Obama with the very same brush. So, from that perspective, I get it. Hitler and the Nazis are an excellent all-purpose tool to demonize your opponents. Just compare them to Hitler! It's easy! It's also incredibly stupid in most cases. If you don't believe me, just check out the last couple of times that I've seen antivaccinationists comparing their opponents to the Nazis or likening vaccine programs to the Holocaust.

Yes, those two examples were really dumb, but I think I just found something even dumber. It's an article by Hilary Butler. (You remember Hilary Butler, don't you? She has a proclivity for vile analogies.) This time around, Ms. Butler pulls out all the stops, asking Are non vaccinators the "new Jews"? Before we get to the "substance" of her article (such as it is), I'll take ignorant historical analogies for $1,000, Alex:

Most adults tread very lightly when criticising the medical profession, particularly when willing parents put their children forward to be used as instruments of the next emotional blackmail campaign. What these same adults don't realise, is that once the clampers are screwed down, and their right to also say "no" has gone, then they too will be lined up, and jabbed without being able to say "no" for themselves either.

And when a person is too scared to say "no", to anything, then choice, … and informed consent has disappeared. And if people stand around and do nothing about it, then they will join Germany in the Hall of Historical Shame. For that reason, this letter has been sent to Fairfax Media.

Ms. Butler, of course, is just warming up. What's gotten her Hitler thing on are two articles published by the Sydney Morning Herald. The interesting thing about the articles (to me, at least) is that one of the two (an editorial entitled Immunisation levels a cause for concern - and timely debate) is actually more deferential to the "freedom" of parents not to vaccinate than much of what I can imagine being published in the U.S. In Australia, it informs us, unvaccinated children are not banned from schools except during outbreaks of vaccine-preventable diseases, which means that, unlike the US, there appears to be no school vaccine mandate. What got Ms. Butler all worked up is the effort on the part of the NSW Labor opposition to introduce a bill to "allow childcare centres and kindergartens the option of banning unvaccinated children." In the U.S., such a bill would be completely uncontroversial. In fact, nearly all U.S. states not only allow daycare centers to ban unvaccinated children but many require it. For instance, the state of Michigan requires the following vaccines: DTaP, hepatitis B, Hib, MMR, PCV, and varicella. It does, however, allow philosophical and religious exemptions. So the hilarious thing is that NSW appears to be proposing to do something that is very reasonable and very defensible. It's only a change from what is done now, which appears to be less restrictive than my country.

Of course, what Ms. Butler objects to is that the articles are sympathetic to minimizing argues that the measure doesn't go far enough because it only provides the option of banning unvaccinated children, pointing out, again quite sensibly, that because daycare centers depend on fees there is a financial incentive not to refuse non-vaccinating parents. To Ms. Butler, this is the equivalent of…well, I'll let her tell you. I'll start with her attack on the second article (Vaccine fears could lead to 'epidemic') because it's the one that brings out the most hyperbole-filled analogies and provokes Ms. Butler to let her Hitler flag fly high:

Your second article is tantamount to fear mongering worthy of the Gestapo. If you had talked to the STATISTICIANS in Australia’s Ministry of Health, you would know that vaccination rates in Australia in 2010 which were published in March 2013, were the highest they have ever been at 92.3% though I find it highly ironic that while 99% of Australian children are on the national immunisation register, your experts are THREE YEARS BEHIND in the compilation and publication of their data, so I would challenge the figure of 92%. The real rate could well be 94 – 95%.

I do so love me some all caps. It's a sign of only the finest crankery. It's also a misunderstanding of what was actually said. The article actually does mention that immunization rates are 92%. That's irrelevant to the point of the article, which is that, while overall vaccination rates are high, there are areas with very low uptake. For instance, it's pointed out that some areas of New South Wales have "lower vaccination rates that Rwanda." The point, of course, is that such pockets of low vaccine uptake are ripe for outbreaks because herd immunity is degraded. but, hey, what's a little fact or two between antivaccine cranks, particularly when they can really get the Hitler juices flowing:

There is a cynical hypocrisy surrounding the medical professions' silence regarding your published inaccuracies on the Australian vaccination rates. Perhaps you need to consider that, like the Germans before the second world war, Fairfax media COULD BE being used by the medical profession, to mindlessly yell "Heil Hitler" - as in the media campaign orchestrated by Dr Michael Wooldridge in 1997.

The first article, as I pointed out, was actually highly deferential in tone to parental rights but ultimately concluded that the proposal to allow childcare centers and kindergartens to ban unvaccinated children didn't go far enough. In fact, Ms. Butler goes beyond just attacking the Herald, generalizing government statements supporting measures to increase vaccine uptake and expressing alarm at low vaccine uptake and likening them to…well, I have to let Ms. Butler tell it again. I just can't capture the combination of spittle-flecked ranting and _argumentum ad Nazium_ with a description:

Are you innocently painting non-vaccinating parents the "new Jews" as a result of the medical profession's complicit silence?

And:

Will the next edict from the medical profession be that you publish a demand, whereby parents must sew a yellow star onto unvaccinated children, as well? You remember where the yellow star led, don't you? Isn't it interesting that the current mob attack on the unvaccinated is very like the sentiment which lead to the anti-Jew pogroms? It's ironic that "history" runs the risk of repeating itself….

Yes, in Ms. Butler's fevered imagination, the Australian health authorities are Nazis who just can't wait to force unvaccinated children to wear the yellow star that Hitler forced Jews to wear. Of course, Ms. Butler knows as well as the editors to whom she writes and anyone who reads her letter know what ultimately happened to the Jews in Hitler's Germany. The yellow star was a step along the way from marginalization to separation from society to elimination in the Holocaust. It was a direct step on the road to the death camps and gas chambers. Does Ms. Butler really think that the Australian government is planning on sending unvaccinated children to the gas chambers and then to the ovens, the way that Hitler sent the Jews to death camps? Probably not. Playing the Hitler card is just a suitably shocking tactic to use to demonize the government health authorities who want to increase vaccination rates in areas where they are low.

If we're going to play the Nazi card, though, it's highly tempting of me to do so with the "autism biomed" movement. After all, what were the Nazis known for besides the Holocaust? Horrific unethical human experimentation (including with children), for one thing. Who in the autism biomed movement is known for unethical human experimentation with children? Why Mark and David Geier, two former "icons" of the autism biomed movement who've fallen on tough times. They first came to my attention several years ago for their rather "original" idea that chemical castration with Lupron would be a good treatment for autism, to help chelation therapy work better. They're also known for running unethical clinical trials approved and overseen by an IRB stacked with their cronies. Indeed, the entire autism biomed movement is little more than unethical experimentation on children using quackery.

See how easy it is to play the Hitler card? I can do it too if I want to. Of course, I only did it this time to make a point, not because I really believe it (unlike, apparently Ms. Butler). I'm also in a benevolent mood because I'm vary happy to have learned that Mark Geier has lost his medical license in the last state in which he had one, Hawaii. That's right. He's now lost his medical license in all 12 states in which he had a license. Not that that has stopped the quackfest known as Autism One from featuring Mark and David Geier as speakers this Saturday, with a talk that looks like a barely warmed over rehash of their same ol' same ol'. I wonder if they'll mention Dr. Geier's most recent loss of medical license. Now he and Andy Wakefield have something to talk about. In fact, Mark Geier has gone Andy Wakefield 11 better in that he's had 12 medical licenses stripped away, and Wakefield's only been struck off once.

In the end, it never ceases to amaze me how little self-awareness antivaccine cranks like Ms. Butler are. It's easy to shout "Nazi!" at your enemies. It's hard, apparently, to see that it's pure nonsens to do so. Still, Ms. Butler has a lot in common with our homegrown antivaccinationists. She'd be right at home at Autism One.

Number theory is chock-full of easily stated problems that are very difficult to solve. One such is the twin primes conjecture, which asserts simply that there are infinitely many twin primes. I'll assume you know what a prime number is. Twin primes are primes that differ by exactly two, such as 3 and 5, 5 and 7, 11 and 13, 17 and 19, or 101 and 103.

Of course, everyone knows there are infinitely many primes. If you have not seen it before, here's one easy way to prove that fact. We assume for a contradiction that there are only finitely many primes, let's say _k_ of them. Then we can make a list: of all the primes. But now we can define a number _N_ by multiplying all of these numbers together and adding one. That is, we have: But we know that _N_ must be divisible by some prime number, since every number has at least one prime factor. (Of course, the number _N_ might itself be prime, but that's OK, since every number is a factor of itself.)

We now ask, what prime number divides _N_? It cannot be any of the primes on our list, since _N_ leaves a remainder of 1 when divided by any of those primes. The only possible conclusion is that there must be a prime number that is not on the list. This contradicts our assumption that our list was complete. It follows that no finite list can possibly contain all the primes, and therefore there are infinitely many prime numbers.

There is also a clever trick for showing that there are arbitrarily long sequences of non-prime numbers. Recall that if _n_ is a positive integer, then by _n!_, read "_n_ factorial", we mean the product of all the integers from 1 to _n_. For example, we have Notice that 6! is a multiple of the numbers 2, 3, 4, 5 and 6. I can use this fact to produce a sequence of five consecutive non-prime numbers, namely 722, 723, 724, 725 and 726. 722 is a multiple of 2, 723 is a multiple of 3, 724 is a multiple of 4, 725 is a multiple of 5 and 726 is a multiple of 6. Do you see the point? If you want _n_ consecutive non-prime numbers, just consider the sequence: The first number is divisible by 2, the next is divisible by 3, the next is divisible by 4, and so on until the last number, which is a multiple of _n+1_. Clever!

So, there are infinitely prime numbers, but also arbitrarily long gaps between primes. There is also the prime number theorem, which tells us that for very large values of _x_, the number of primes smaller than _x_ is closely approximated by (A more precise statement of the theorem can be found here.)

None of this really tells us much about twin primes, alas. But we do now know that there is some finite number with the property that there are infinitely many pairs of primes by differ by no more than that number:

On April 17, a paper arrived in the inbox of _Annals of Mathematics_, one of the discipline's preeminent journals. Written by a mathematician virtually unknown to the experts in his field -- a 50-something lecturer at the University of New Hampshire named Yitang Zhang -- the paper claimed to have taken a huge step forward in understanding one of mathematics' oldest problems, the twin primes conjecture.

Editors of prominent mathematics journals are used to fielding grandiose claims from obscure authors, but this paper was different. Written with crystalline clarity and a total command of the topic’s current state of the art, it was evidently a serious piece of work, and the Annals editors decided to put it on the fast track.

Just three weeks later -- a blink of an eye compared to the usual pace of mathematics journals -- Zhang received the referee report on his paper.

"The main results are of the first rank," one of the referees wrote. The author had proved "a landmark theorem in the distribution of prime numbers."

What is that finite number? According to the conjecture, that number should be two. Here's what Zhang achieved:

His paper shows that there is some number N smaller than 70 million such that there are infinitely many pairs of primes that differ by N. No matter how far you go into the deserts of the truly gargantuan prime numbers -- no matter how sparse the primes become -- you will keep finding prime pairs that differ by less than 70 million.

70 million might seem pretty far from 2. What you have to remember, though, is that the difference between 2 and 70 million pales in comparison to the difference between 70 million and infinity. So Zhang's theorem is definitely a big deal!

Molluscs have amazing super-powers.

But you know what? So do humans. We air-breathing terrestrial bipeds are able to enter strange alien worlds and return with a digital record of the events that even the lubbers among us can appreciate.

“Because dark energy makes up about 70 percent of the content of the universe, it dominates over the matter content. That means dark energy will govern expansion and, ultimately, determine the fate of the universe.” -_Eric Linder_

It's been a while since we've spoken about dark energy, and we were just talking about Einstein's greatest blunder, so let's just dive right in.

This is our observable Universe, as unveiled by the Hubble Space Telescope. With hundreds of billions of galaxies stretched out some 41 billion light years in all directions, finding out about what our Universe was like in the distant past, the recent past, and what it's like today is limited only by our willingness to look. In particular, there are three great sets of observations that tell us ever so much about the Universe on the largest scales.

1.) THE WAY GALAXIES CLUSTER TOGETHER ON THE LARGEST SCALES. By looking at huge, tremendous surveys of galaxies, we can see how the visible matter in the Universe has clustered, clumped, and grouped together, as well as where it _hasn't_, and has left us great cosmic voids. By putting various ingredients into a model Universe governed by General Relativity, we can also simulate how structure should form in our Universe. Where the simulations and the observations match up, that tells us what's in our Universe.

2.) THE TEMPERATURE FLUCTUATIONS IN THE COSMIC MICROWAVE BACKGROUND. By looking at the temperature fluctuations -- the hot-and-cold spots -- in the CMB, we can know what the Universe looked like in terms of overdensities, underdensities, and how they're clustered with respect to one another all the way back at a time when the Universe was just some 380,000 years old! Because the light has had to travel for nearly the entire 13.8 billion years that the Universe has been around (it's been traveling for 99.997% of the Universe's history), we can find out information about what the Universe was like back then, but _also_ how it's expanded since then. This pattern of fluctuations also tells us what the various combinations of ingredients are in our Universe.

3.) DIRECT OBSERVATIONS OF WELL-UNDERSTOOD OBJECTS AT VARIOUS DISTANCES/REDSHIFTS IN THE UNIVERSE. Everything from variable stars to properties of galaxies to distant supernovae help us get a handle on this, the cosmic distance ladder. This tells us how the Universe has been expanding since as far back as we can measure until the present day.

When these three data sets are combined -- and we can combine others, too, but these three are the _best_ data sets we have -- they tell us that there's matter in the Universe, about 31-32% of the Universe is matter (most of which is dark matter), and that there's another type of energy, DARK ENERGY, that makes up the rest.

So, you ask, just _what is_ dark energy, and how do we know?

In principle -- and by in principle, I mean in General Relativity -- matter, energy, topological defects, and pretty much anything else that you throw into your Universe is going to affect how your Universe expands because of two properties inherent to it: it's ENERGY DENSITY and its PRESSURE.

Because of the way the Universe is observed to expand, and because of the known way that matter (yes, even dark matter, according to General Relativity) behaves, we can infer something about the energy density _and_ pressure of dark energy. In particular, we know that dark energy's pressure is NEGATIVE, and that it's _quite_ negative.

In General Relativity, we can relate the pressure of any component of the Universe to its energy density by the simple equation:

_ρ _= w P / c²,

where _ρ_ is the energy density, P is the pressure, c is the speed of light, and w is JUST SOME NUMBER.

According to the best data we have right now, W is equal to -1. Now, as time goes on, we hope to constrain it better; we can say it's probably about -1.00 ± 0.08 right now, which is pretty good.

Now, here's the thing: in THEORY, the pressure of different things in cosmology goes in increments of 1/3. For example:

* Radiation has w = +1/3, like photons and ultra-relativistic matter. * Matter, both normal and dark matter, has w = 0, or is virtually pressure-free. * Cosmic strings, or 1-dimensional topological defects, have w = -1/3. This is the border between what would cause a Universe to accelerate (more negative than this) or not. * Domain walls, or 2-dimensional topological defects, have w = -2/3. * A cosmological constant (or textures, a 3-d defect) has w = -1. Those are the easy possibilities.

But dark energy could _also_ be something weird. It could be a field, whose relationship between pressure and energy density changes over time. It could be coupled to something we don't understand. It could be really, really weird, and our measurements of w = -1, to the best we can see, could only be what the Universe is _so far_.

So we've attempted to look for a change in w over time. We've attempted to look for departures from w = -1. We've attempted to look at different models and their signatures.

Know what we've found?

The farther back into the past we look, the more and more consistent everything appears to be with the COSMOLOGICAL CONSTANT option.

The cosmological constant option has the theoretical bonus of being:

* easily explained, * inevitable (in that it must exist, even though its value could be 0), * and requires no new physics beyond the standard model/GR to explain. We're going to keep exploring different variants of dark energy, quintessence, scalar field-driven dark energy, etc., of course. But theoretically, there's no motivation unless we see _some_ sort of evidence that tells us that dark energy is something more (or other) than a simple cosmological constant. And trust me, WE'RE LOOKING.

This doesn't mean dark energy _is_ a cosmological constant, it just means that this is the best working hypothesis until evidence suggesting otherwise comes along, and such evidence does not exist today. That's the best we've got, so far.

The Boy Scouts have ended their ban on openly gay members. Gay scout leader still have to pretend they are not gay.

For months I subscribed to too many podcasts, and so wasn't listening to a lot of music. But lately I've made an effort to rectify that. Here's what I've been bopping to. * Apples In Stereo – _Travellers In Space And Time_ (2010). Lots of vocoder!

* David Bowie – _Pin Ups_ (1973). Glam covers of 60s British pop tunes. * Brimstone Solar Radiation Band – _Solstice_ (2005). Norway's finest psychedelia! * Jet – _Shaka Rock_ (2009). Stonesy, amazingly derivative and amazingly good. * Midlake – _Courage of Others_ (2010). Mournful, close two-part harmony, guitars, flute, always on the brink of over-earnestness. * Norm Sherman – _Esoteric Order of Sherman_ (2012). Masterfully genre-spanning geek comedy songs. * Sword – _Age of Winters_ (2006). Black Sabbath devotees lamenting the passing of the aurochs. * Tame Impala – _Lonerism_ (2012). Australian Lennon soundalike plays spaced-out pop under the direction of ex-Mercury-Rev producer. * Yes – _Fragile_ (1971). Exuberantly intricate prog rock. Now tell me about some more good albums!