Mothra Invades the Science Cabaret

By Larry Klaes

The Monday after the Thanksgiving holiday in the States is always gloomy as people readjust to work after the long weekend. So let’s do something light-hearted for today with a look at what evolution can produce in the hands of Japanese film directors. Larry Klaes considers Mothra, a tale of a small creature grown large, and the demands its unexpected size would make if such things existed in the real world. Larry has been to a ‘science cabaret’ inspired by the Café Scientifique movement, which brings science to the public in informal settings. What better format to convert cinematic fantasy into science? We need to get interstellar ideas into such venues.

When looking for lessons in science, one might be forgiven for not considering the Japanese monster films of the latter half of the Twentieth Century as a prime source for such material. Yet a lesson in science is exactly what was extracted from one particular member of that genre, courtesy of entomologist (a.k.a. bug specialist) and juggler Dr. Paul S. Robbins of Cornell University’s New York State Agricultural Experimental Station in Geneva. Robbins discussed the “Moth vs. Myth: The Science Behind the B-Movie Monster Mothra” at Ithaca’s Science Cabaret.

Warming up his audience with a series of slides of various insects in all their colorful glory accompanied by techno music, Robbins began his talk with a personally edited version of the 1961 film Mothra.

Mothra poster

The plot involves a gigantic moth named Mothra that invades Japan in search of twin singing fairies that had been kidnapped by some explorers who had visited their native land, a place called Infant Island. The kidnappers hoped to make themselves rich by showcasing these unusual little creatures to the public. What they hadn’t planned on was the wrath of Mothra.

The film displayed Mothra in all its stages of development, from its start in a giant egg to its becoming a giant swimming larva (caterpillar), with its mature winged form eventually emerging from a giant cocoon wrapped around Tokyo Tower. The adult Mothra wreaked havoc with numerous model vehicles and buildings by flapping its giant wings, until the protagonists of the film finally figured out a way to return the fairies to the monster moth and stop its attacks.

Putting aside for a moment whether a member of the insect order Lepidoptera being the size of a large aircraft could ever exist in reality, let alone swim in the Pacific Ocean and attack major cities in search of some tiny singing fairies, Robbins then gave a brief lesson in insect anatomy.

Among the features common to most insects are a hard, waxy exoskeleton for the structural integrity of their bodies, rather than an internal skeleton made of bone. Another common element is the lack of lungs for taking oxygen into their bodies and removing carbon dioxide. Instead, insects use a collection of tubes called tracheae to diffuse these gasses directly to and from their tissues.

The method of insect respiration having been established, Robbins questioned whether a moth as big as Mothra would be able to breathe. The much longer than usual distances the essential gasses would have to travel around the monster moth’s body “means a slower delivery, but the larger tracheal diameters could also speed up the process.”

Mothra in larval form

Robbins also speculated on whether such a huge moth could actually fly in the air, emphasizing the point that “size really does matter” in this situation. Driving home the concept of “surface area to volume ratio” to the crowd, the Cornell entomologist – with the help of some juggled ping pong, tennis, and bowling balls, among other items – demonstrated that the volume of an object increases far faster than its surface area.

Image: As startled helicopter crews look on, Mothra in its larval form destroys Tokyo Tower in the 1961 film.

What this means for the monster moth of Infant Island is that “a scaled up version of your average porch light moth would be unable to manage the challenges Mothra faced,” concluded Robbins. “Mothra would never be able to get off the ground, due to the limited surface area of its wings.” Mothra would also be unable to swim in its giant caterpillar stage as it did during the film.

As for the tales told by Mothra, while the reality of the main character in the film is iffy at best, Robbins suggests that when viewing this and most other such fictional entertainment, one should always “enjoy the story… but think about the science,” even if it is a giant moth that swims, flies, and attacks models of major cities.

Science Cabarets are inspired by the Café Scientifique movement, which started in Europe in the late 1990s and has spread rapidly. Cafés Scientifiques promote public engagement with science by eschewing a lecture format in favor of informal talks on topics of broad interest, which are used as a jumping-off point for group discussion.

Planetary Systems in Miniature

‘Planemos’ are planetary mass objects not much larger or heavier than Jupiter. The emerging technical term for them is ‘isolated planetary mass objects’ (IPMO), although the nomenclature is still evolving. Back in 2006, Ray Jayawardhana (University of Toronto) challenged the American Astronomical Society’s Calgary meeting to consider how our definition of ‘planet’ is blurred by planemos that act much like little solar systems. Consider Jupiter itself, a small system doubtless born with its own disk of dust and gas that produced the raw materials for its larger moons.

Backing up such thinking was the brown dwarf 2M1207, known to have a planetary companion eight times the mass of Jupiter and now shown to be surrounded by a disk of its own. Thus it comes as no surprise that Jayawardhana, following up this work with Alexander Scholz (University of St Andrews), has been using the Spitzer Space Telescope to study eighteen planemos in a star cluster in Orion. At three million years old, young stars tend to be surrounded by gas and dust that glows in the infrared, a marker of the raw materials for planetary formation. About one-third of the planemos under study show similar disks.

So ‘planetary’ systems may form even in the presence of a planemo instead of a central star. What’s left hanging is the question of where the planemos come from in the first place. They’re smaller than brown dwarfs (with masses close to or below the deuterium-burning limit) and may well be planets expelled from young planetary systems. Or perhaps, say the scientists, they’re stellar embryos ejected from mini-clusters or multiple star systems. Whatever the case, the ? Orionis cluster offers the largest population of these objects yet identified.

From the paper (internal references deleted for brevity):

“…our results fit into previous claims for a T Taurilike phase in the planetary mass regime… Disk fractions and thus lifetimes are similar for objects spanning more [than] two orders of magnitude in mass…possibly indicating that stars, brown dwarfs, and IPMOs share a common origin. Star formation theory thus has to account for a number of objects with masses below the Deuterium burning limit.”

Interesting work, because in recent years the study of brown dwarfs has shown that they have what Jayawardhana and Scholz call ‘circum-sub-stellar disks’ with life times between five and ten million years, which makes them not dissimilar to other kinds of stars. We’re deep into what’s known as the initial mass function (IMF), which describes the distribution of stellar masses in a formation event in a specified volume of space. Just how that IMF is extended to encompass findings like these, moving down into the realm of the giant planets, will help us to probe its apparent universality in relation to star formation theory.

Thus the similarities between objects of vastly different sizes has to be factored into our thinking about how stars form. Again we note, in the presence of those gas and dust disks, the apparently ubiquitous phenomenon of planetary formation. Are we really looking at a universe that seems to seed almost every kind of star and even giant planets with companions? The paper, to be published in The Astrophysical Journal Letters, is “Dusty disks at the bottom of the IMF,” available online.

Is Luna a Celestial Rarity?

Having just written about dust formation around HD 23514, a Sun-like star in the Pleiades, I was drawn to this quote by Nadya Gorlova (University of Florida, Gainesville), whose recent work suggests that if moons like our own were common, we’d be seeing more dust than we do around other stars. “When a moon forms from a violent collision, dust should be blasted everywhere,” says Gorlova. “If there were lots of moons forming, we would have seen dust around lots of stars — but we didn’t.” By contrast, the UCLA study on the Pleiades sees major collisions as common in young solar systems, though to be sure it didn’t focus its conclusions on the 30 million year age range, as the Florida study did.

Gorlova’s team used data from the Spitzer Space Telescope and operated under current assumptions about lunar formation, in which an impactor the size of Mars is thought to have struck the Earth, creating a vast debris field that fell into Earth orbit and eventually became the Moon. The theory sets Earth’s Moon apart from the rest of the Solar System, where planetary satellites seem to have formed at the same time as their planet or else were captured by that planet’s gravity. If our Moon is anomalous, then how often will we find exoplanets orbited by similar moons?

Earth and Moon

The study looked at four hundred stars in the range of 30 million years old, which is the age our Sun is thought to have been when the Moon formed. The result seems stark: Only one of the four hundred shows the kind of dust cloud that flags such a collision. From this, the team calculates a five to ten percent chance that a given solar system will create a moon like Earth’s, and that’s a high estimate. “We don’t know that the collision we witnessed around the one star is definitely going to produce a moon, so moon-forming events could be much less frequent than our calculation suggests,” says co-author George Rieke of the University of Arizona, Tucson.

Image: Our Earth-moon system, photographed here by NASA’s Galileo spacecraft in 1992, might be somewhat uncommon in the universe. New evidence from NASA’s Spitzer Space Telescope suggests that moons that formed like ours — out of colossal collisions between rocky bodies — might arise in, at most, 5 to 10 percent of planetary systems. Credit: NASA/JPL-Caltech.

HD 23514, the star examined by Benjamin Zuckerman’s team at UCLA, is about 100 million years old and compared to most stars of its age, virtually choked by dust. But the UCLA work on this star (and earlier on the Sun-like BD+20 307) suggested that younger stars — in the 10 million year range or younger — are hotbeds of collisional activity of the sort that forms planets and, one would assume, breaks them apart to form moons. Perhaps our Moon is simply a late arrival, with other moons like it more likely to form earlier in the history of a given star’s development.

In any case, the Florida study makes a strong case that by the time a star is 30 million years old, it’s likely to have finished the planet formation process, so collision-generated moons from that point on are less likely. It would be interesting to have these two teams in the same room for debate, something conference organizers should note for future reference. Meanwhile, the paper is Gorlova et al., “Debris Disks in NGC 2547,” The Astrophysical Journal 670 (November 20 2007), pp. 516-535 (abstract).

‘Doomsday Vault’ Prepares to Open

One of the things I like about Norway is that the government there requires at least one percent of public building budgets be devoted to artwork. Thus the plan for the Svalbard Global Seed Vault, which is designed as a hedge against planetary catastrophe. At the Spitsbergen site near the town of Longyearbyen, highly polished metal sheets installed on the roof and front of the entrance portal will create a sparkling sculpture visible for miles around, lit by the Sun or by fiber-optics during the long Arctic winters.

Town of Longyearbyen

I would imagine Norwegian artist Dyveke Sanne took the commission as quite a challenge. How do you capture the spirit of what is essentially a fail-safe backup of the world’s vital food crops? Assume for a moment that we do get a massive blow one day from an Earth-crossing asteroid and our survivors, provided there are some, will want to re-start agriculture with the basic crops — wheat, barley, peas, corn. And not just the basics, for it may be necessary to start over again in almost any part of the world.

Image: The town of Longyearbyen, near the site of the Svalbard Global Seed Vault. Credit: Heidi Eriksen, Ministry of Agriculture and Food.

The site on the Svalbard archipelago can hold up to 4.5 million seed samples, meaning almost every variety of food crops on the planet can find a home there. The trick is to keep the seeds safe for centuries, up to a thousand years. In mid-November, the site began the crucial cooling down phase preparatory to its official opening early next year, using a 30 kilowtt refrigeration system brought over from the mainland. Over the next two months, the temperature of the sandstone rock around the vault will drop from the current -5 degrees Celsius to -18 degrees.

Magnus Bredeli Tveiten works with Statsbygg, the Norwegian government’s Directorate of Public Construction. Having surveyed the project from top to bottom, the Seed Vault’s project manager is confident of the result. “We ran a lot of computer simulations to determine the optimum approach and believe we have found a very effective and especially energy efficient way to establish reliably cool conditions inside the vault,” says Tveiten. “We believe the design of the facility will ensure that the seeds will stay well-preserved even if such forces as global warming raise temperatures outside the facility.”

It’s a remote place, this doomsday vault, located at the end of a 120-meter tunnel blasted into a mountain on what is surely one of the least accessible populated places on the planet. Long-term cooling will be maintained by natural permafrost, snow and ice, supplemented by a 10 kilowatt refrigeration system once the target temperatures are reached. With Spitsbergen now into its three month night, cooling should proceed without difficulty. As to that artwork, consider it a monument to human foresight, a marker for a resource we may hope we’ll never have to use in the kind of emergency it seeks to ameliorate.

A long way from Svalbard to Centauri? Perhaps, but bear in mind that the first priority of a space-based infrastructure — the kind that will eventually produce the technologies that make at least robotic interstellar missions possible — is to protect the most precious asset we have, our own planet. While we wrangle over Arecibo funding and question whether we should spend the money to identify dangerous asteroids, the Svalbard project is a case of taking the long view in case we’re foolish enough to let our environment be destroyed.

Cosmic Ray Origins Quickly Back in Play

Interesting to see how quickly the story on high-energy galactic cosmic rays has shifted in the past week. Recent work at the Pierre Auger Observatory in Argentina pointed strongly to the centers of active galaxies, where supermassive black holes are found, as the likely source. These Active Galactic Nuclei (AGN) stood out in analysis of the 27 highest energy events recorded at the Auger site because known AGNs seemed to correlate (in terms of direction) with the incoming cosmic rays.

In any case, the idea that these tortured galactic centers could be the source made obvious and intuitive sense. But is the origin of these most powerful of cosmic rays — with energies up to 100 x 1018 electronvolts — now understood, or is it just a statistical correlation that won’t stand up to continued scrutiny? The University of Utah-based High Resolution Fly’s Eye (HiRes) collaboration has been trying to check the correlation based on events in northern hemisphere skies. And here’s the gist, as reported by Katherine Sanderson in an article on nature news:

[HiRes] has tried to check this conclusion against data from ultra-high-energy cosmic-ray events they detected in the northern sky. The researchers used the Auger team’s parameters for factors such as the maximum distance of the active galactic nuclei from Earth and the maximum angle the ray will be bent by interactions with magnetic fields, and looked to see whether the active galactic nuclei could also explain their events. Their results suggest that they don’t.

“They see correlations, we do not see correlations,” says Gordon Thomson, one of the HiRes collaborators. Only 2 of the 13 events looked at by the HiRes team correlated with active galactic nuclei.

Although this first check on the Auger findings hasn’t been published yet, we already seem to be in familiar territory. Cosmic rays have taken us down many a crooked path in the past. Whether HiRes is on to something may depend on whether their dataset and Auger’s are comparable, given that HiRes seems to have few events in the highest-energy range. But we won’t know more about the specifics until the paper appears. Even if Auger is eventually confirmed, the deeper question remains: How does even an AGN produce the accelerations needed to produce these cosmic rays? That question should continue to confound us no matter where in the sky we trace the origin of these mysterious high-energy particles.