Light at the End of the Solstice: Sunrise, Sunset, and Celestial Mechanics

Most people are familiar with the idea that the length of the day varies with the seasons. Especially for those in the more northern latitudes, it’s an obvious feature of the winter that the sun rises later and sets earlier than in the summer. Throughout history and across northern cultures, the winter solstice is celebrated to herald the imminent return of light; after the shortest day, things can only get brighter!

One would expect that following the winter solstice — the shortest day — the sun will start both rising earlier and setting later in the day in order to make it longer. That is, we’d expect the sun to be highest at noon and have sunrise and sunset start moving away symmetrically on either side as the days get longer. What surprises many, and left me at a partial loss to explain when asked about it, is the fact that this is not so. In fact, the sun continues to rise later in the morning for days following the winter solstice — and begins setting later days before it! The reason is truly celestial.

Continue reading

Acropolis Now: The Rolling

As I detailed last month, my former residence, presciently nicknamed Acropolis, has been lifted into the air by hydraulic jacks and left to rest on wooden towers known as ‘cribs’. This was done for a reason: the house needed to be moved eight or nine feet toward the street in order to make room for townhomes in what was the house’s backyard. Heady stuff, I know.

Lifting the house up on stilts was impressive enough, but I couldn’t quite imagine how they were then going to move it thereafter. On the Tuesday before last, I found out.

Continue reading

Acropolis Now: The Raising

I was until recently among a crazy troupe of rag-tag whippersnappers who shared a dream: to live affordably on Capitol Hill in a free-love commune, throwing wild parties yet responsibly engaging with our community and the environment. We named our hilltop palace Acropolis, but our Gods did not demand sacrifice. We were starry-eyed lute-toting moon sailors with a heading fixed on paradise.

That utopian fantasy was not realized for at least twice as many reasons as you can imagine, and one of them is this: our landlords bought the house in order to literally lift and move it west about three meters in order to build a condominium in the backyard. Only in the GREATEST COUNTRY ON EARTH, right? We all cleared out as agreed when it came time to do this move, and I was lucky enough to witness and document the first phase of it yesterday: the Raising.

Continue reading

Book Review: “The God Delusion” by Richard Dawkins

The God Delusion is a fairly recent nonfiction work by the prolific evolutionary biologist and militant atheist Richard Dawkins. Published in 2006, 30 years after he rose to prominence with the work for which he is best known and which I highly recommend, The Selfish Gene, there is only a little biology to be found on the pages of the The God Delusion. Drawing from well-documented anecdotal evidence and swelling with reason rigorously applied, the book is an orderly and unapologetic assault on belief in God, organized Abrahamic religion, and a culture that sheepishly looks the other way when confronted with either.

A common criticism of Dawkins is that he’s just so nasty when he dissects religiosity; why, ask the faint of conviction, can’t he just leave well enough alone, or at least be respectful when he can’t? Having read several of his books, I can safely declare that Dawkins is actually eminently reasonable. He is deferential to individuals he respects, admits when he’s at risk of speculating more than analyzing, and draws distinction between harmless naivete and menacing intent. He successfully identifies real harms derived from faith-based world views and religious institutions and makes a case for his politely and eloquently expressed incredulity and outrage at them. A careful reading of the The God Delusion should convince the thoughtful believer, explicitly his target audience, not only of atheism but of his brand of powerful evangelistic atheism. Rather than respecting faith, we should all become foot soldiers in the war to eradicate it.

Continue reading

happy pi day!

Today is March 14th, which is often written in the west as 3/14. Looking at it this way, the date bears a striking resemblance to a common approximation for pi, the mathematical constant which expresses the ratio of any Euclidean circle’s circumference to its diameter. For this reason, today is celebrated by math enthusiasts the world over as Pi Day, a day on which the wonders of pi (and usually also pie) can be shared by one and all. There is even a website dedicated to pi day (and of course associated merchandising: check out this awesome clock). On the occasion of this delightful holiday, I would like to remind the reader about several interesting things about pi.

Continue reading

contraception, gay marriage, and global warming

In absolute defiance of common sense, the contraception “debate” that I was hesitant to write about — twice — seems to continue, at least by proxy. On leap day, Rush Limbaugh weighed in on that woman who was denied to speak at the House panel ostensibly about birth control. As is usual, Rush Limbaugh had nothing valuable to add to the discussion, but his particular word choice led to controversy and an incredible flight of advertisers from his so-called Excellence In Broadcasting network. His joke of an apology was summarily dismissed and Jon Stewart brilliantly ridiculed the whole mess. It’s so bad that now other right-wing talk radio stars are being targeted for sponsorship withholding.

But while Rush’s particular comments appear to be a lightning rod for focused criticism, the spirit of his remarks forms the cornerstone of conservative opposition to publicly underwritten or otherwise widely accessible birth control. It cannot be that the right protests government spending per se, since it tends as a rule to support robust defense spending, foreign intervention, big oil subsides along with increased and oversight-free drilling, expensive tax cuts for the wealthy, and so on. The BBC has a lovely summary of the major arguments against contraception:

  • Contraception is inherently wrong because it is unnatural, anti-life, and separates sex from reproduction.
  • Contraception leads to negative consequences since it prevents potentially useful individuals from being born, can be used for social engineering or eugenics, and carries health risks.
  • Contraception promotes “immoral behaviour” by encouraging marriage-free sex primarily for pleasure.

Let’s consider these points in turn.

Continue reading

Iran and nuclear physics

Shit’s heating up with Iran. There’s an intended pun here, since the news of the day is the IAEA (the ‘nuclear watchdog’ arm of the UN) claims it can confirm that Iran is enriching uranium at up to 20% at a heavily guarded underground bunker. According to the IAEA’s own report from last November (pdf here), this was all according to plan and was reported to the IAEA in June of 2011. So the fuss appears to be that it is actually happening, and predictably the fuss is a loud one from typical hypocritical whiners like the US about how “this means Iran’s building a bomb which will destabilize the region and oh mercy won’t somebody think of the children.”

(To make my point, it’s time for an aside for those unfamiliar or curious, as I was, about uranium enrichment and its role in making deadly weapons. If you are already an expert on these subjects, then please skip to the close parenthesis.

Recall from high school chemistry that all matter is composed of atoms, each of which in turn contains a nucleus at its center made up of electrically neutral neutrons and positively charged protons. These nuclei are stable against the incredibly repulsive force of those protons through a medium called the strong nuclear force [clever!], but for very heavy nuclei — those containing lots of protons and neutrons — the strong nuclear force could be subverted by the weak nuclear force [yay!] if only there were a little energy to get those protons ‘over the hump’ as it were. This would cause the nucleus to split into two [sometimes three] pieces, thereby releasing all that energy the strong force was keeping pent up, in a process called fission.

The famous Manhattan Project was commissioned during the second world war in order to kill unsuspecting Japanese civilians by finding a way to unleash this explosive force on command. The idea was to get a lot of these heavy nuclei together and hit them with something. More precisely, certain nuclei are unstable enough that if you hit them with a neutron, they will split apart into two smaller nuclei, some extra free neutrons, and a fair amount of energy. Those neutrons hit other unstable nuclei, and before you know it, you have an explosive chain reaction.

It turns out a good choice for the heavy nuclei are a particular isotope of uranium, U-235. You hit one with a neutron, it becomes U-236 just long enough to break apart in a shower of smaller nuclei, neutrons, heat, and light. The problem is that the vast majority of uranium on earth is a much less radioactive (and hence less unstable) isotope, U-238. Wikipedia says U-238 is about 140 times more abundant, and that’s saying something since there isn’t much of that lying around either. While radioactive, you just can’t get the chain reaction with this heavier stuff. To make matters worse, it’s pretty much all mixed together: there aren’t chunks of pure U-235 conveniently scattered about the New Mexico desert. So what did those clever Manhattan Project scientists do? Basically, they devised elaborate techniques to ‘enrich’ the uranium, or in other words to toss the U-238 and keep the U-235.)

But now let’s consider the hype. The same wiki article linked above and quoted below indicates that commercial nuclear reactors often use uranium enriched to between 3 and 5% U-235, while noting that ‘research reactors’ — so called for their use in producing radioisotopes for medical research and treatment, among other things — can use enrichments as high as 19.75%. Indeed, the 20% number bandied about so hysterically is a threshold between Low Enriched Uranium (LEU) and High Enriched Uranium (HEU). Apparently a ‘crude weapon’ could be fashioned with the best LEU, but ‘usually’ weapons-grade uranium is 85% HEU or better; Little Boy of Hiroshima fame was 80%, and that bomb was crude compared to today’s standards. The nuclear cores of atomic submarines usually contain ‘at least 50%.’ Perhaps most tellingly, modern US nuclear weapons are comprised of two stages: the first is a different nuclear fuel, Plutonium-239, to create an initial nuclear explosion, which then sets off a chain reaction in a 40-80% HEU  core. Even with bottomless pockets funding a half century of research and development to create a two-staged nuclear explosive, we still need to enrich that stuff so that the concentration of U-235 is at least 50 times higher than in nature. The best Iran is talking about now is only half that concentration.

Could Iran use this uranium they are enriching to create a nuclear bomb? Probably, but only a very crude one. But could uranium enriched to that purity also have legitimate non-WMD purposes, like what Iran has been saying all along? I believe so, based on a cursory investigation into the nature and uses of enrichment. And all this is a totally separate question to whether Iran would dare use a nuclear bomb even if they could make one. There is a lot more to say about the present situation with Iran, and I plan to say at least some of it soon, but the fuss about enrichment activities is clearly less about safety or stability and more about regional control and possibly even warmongering jingoism. Look out below?