Wednesday, March 12, 2008

Carancas: Per usual, was highly unusual

Every time we turn a corner in exploring the known Universe, we encounter phenomena that raise more questions than are answered. Often we are satisfied with the good answers, but whole schools of thought appear when the vines of hypothesis are cleared away.

It’s cliché, but that’s why they call them clichés. More often than not, they’re true.

And again this week we are reporting the results of studies from League City, Texas and the Lunar and Planetary Science Conference which are leaving specialists in their fields feeling like they’ve tried to sip from a fire hose, or, if you prefer, an effect once cliché in Washington, and a phenomena that may still be true; MEGO, an appropriately NASA-sounding abbreviation to indicate a topic’s “Glaze Factor."

My Eyes Glaze Over. So it was when the Martian Chronicle sounded a Heads Up to we Selenologists out here by wandering from breakout sessions on Sol IV, stumbling out of lectures from sheer overload and into sessions on NASA’s proposed Internationally-shared platforms and communications nodes when Moon Traffic Control really becomes a problem, NASA believes, in only a bit more than a decade.

We often forget the surface of Earth’s Moon is roughly the size of the land area of Africa. If the legend is correct that the only two registered automobiles in Kansas in 1902 actually collided at a rutted four-way intersection, then the odds will start getting tight, and sooner than most of those paying for this show can yet imagine. NASA is right to plan to avoid the expected.

But what of the unexpected?

Certainly we have a pretty good bead on the speeds of cometary debris and other regular hazards, including those that are man made, while traveling in Earth Orbit, Trans Lunar Space and possibly in Lunar Orbit. If Vanguard can survive in orbit for fifty years, then it follows that the incidence of truly anomalous fragments of matter are quite rare. Thanks to legendary Fred Whipple, we can even build robust shielding with gapped double hulls, for most scenarios.

But… and there is a but in every crowd, the surface of our Moon testifies of bombardments Grand, old and new, from every direction, and possibly with periodicity. And the existence of the Moon itself testifies of bombardment. We should take a hint, and remember that while the known Universe is headache-producing in imagined size, the Solar System, the Inner Solar System and the Earth Moon System in particular, is getting smaller all the time.

And our understanding even of our relationships with one another is still rather primitive by the standards of our ideals, let alone the challenges of survival on the Moon.

And what of Carancas? Inquiring minds want to know, and what we’re learned is whatever created the buzzworthy hole hewn out in Peru last September wasn’t your average meteoroid.

I’ll hand over, with Hat Tip to MIT’s essential Ksjtracker, for background, and with only these snippets as a teaser:

last September’s news flurry of a perplexing, some say steaming, hole in the ground - rapidly filled by ground water - in the Peruvian country side. Some locals claimed the fumes made them ill. Last we heard, it was a meteor strike, but a puzzler. That still looks to be the case, a Brown U. professor told the Lunar and Planetary Society meeting in Texas yesterday.”

The news, in brief, is that the Carancas Fireball was not merely a bolide from above. It must, it says here, have hit the ground at around 15,000 miles per hour to have made such a deep hole, thrown debris hundreds of yards, and, it turns out, left telltale microscopic shock damage in mineral grains. (Imagine hitting the ground so hard that the sand doesn’t just scatter, it breaks). And bam, there go standard explanations of what is supposed to happen to all smallish stony meteoroids when they hit the atmosphere - which is to break apart, slow down, and perhaps detonate Tunguska-style as they dump kinetic energy abruptly into the air. One then gets a debris field of meteorites, not one big plunk. (Iron meteors, in contrast to stony ones such as this was, do often stay intact.)

The prof thinks, somehow, this one may have morphed inside its fireball into a streamlined shape and punched through the air in one piece…”

Reuters Maggie Fox reports - as the release has it - that the terminal velocity was more than 40 times what experts would have expected. The professor explains to her the pieces should have just hit, “plop” - nothing like what actually happened ; National Geographic News Richard Lovett writes it “punched holes in long-held theories” and has the prof. describing it as like a needle that pierced the atmosphere ; Tech Herald Rich Bowden (pretty small outlet but good hed: How a misbehaving meteorite changed the rules ) "

Grist for the Mill: Brown University Press Release