An Unusual Passage Through Customs

The Mobile Quarantine Facility, now on display at the
Smithsonian National Air and Space Museum.

Anyone old enough to remember July 24, 1969—the day Apollo 11 safely splashed down in the Pacific to end their lunar landing mission—can probably remember what happened next: NASA quarantined the Apollo 11 astronauts. Fearing that they might have been infected by “moon germs” and protecting against a worst-case scenario, they put the Apollo crew in their Mobile Quarantine Facility (MQF) immediately after they splashed down. Converted from an Airstream trailer, the MQF contained living and sleeping quarters, a kitchen, and a bathroom. By keeping the air pressure inside the facility lower than the pressure outside, and by filtering the air before it was vented out, quarantine was assured. They remained in it while they were flown from the aircraft carrier U.S.S. Hornet to Honolulu and then lifted by crane into another plane and flown to the Johnson Space Center in Houston where the MQF was hooked up to a larger living space, the Lunar Receiving Laboratory. Only after scientists were sure they were not infected with any contagions were they allowed to emerge, 65 hours later.
  Lesser known, though, is that on their way to Houston, customs inspectors at the Honolulu airport had a little fun with Armstrong, Aldrin and Collins. They filled out a General Declaration form for the astronauts, recording their trip from Cape Kennedy to the Moon and back to Hawaii. Under the cargo category, the form lists “MOON ROCK AND MOON DUST SAMPLES” and after “Any other condition on board which may lead to the spread of disease,” they entered “TO BE DETERMINED”(!) The form was duly signed by Commander Neil A. Armstrong, Colonel Edwin E. Aldrin Jr. and Lt. Colonel Michael Collins.

The U.S. Customs form signed by Apollo 11 astronauts Neil Armstrong, Buzz
Aldrin and Michael Collins after their return to Earth on July 24, 1969.

   Much has changed in the 42 years since that historic mission, and it’s hard to believe that we’ve not returned to the Moon in almost four decades. Richard Nixon, who famously welcomed the astronauts back to Earth from outside the Mobile Quarantine Facility onboard the U.S.S. Hornet is no longer with us, and all three astronauts are now in their 80s. For anyone interested, the Mobile Quarantine Facility is now on display at the Smithsonian National Air and Space Museum. There will be no quiz this week as a nod to spring break.

Richard Nixon welcoming the astronauts back from outside
the Mobile Quarantine Facility onboard the U.S.S. Hornet.

Flight of the Bumblebee

This week I want to dispel the myth that according to the laws of aerodynamics, bumblebees shouldn’t be able to fly. I traced the inception this rumor back to the 1934 French book on entomology, Le Vol des Incectes, by Antoine Magnan. He states in the introduction that “First prompted by what is done in aviation, I applied the laws of air resistance to insects, and I arrived at the conclusion that their flight is impossible.” Supposedly, taking the weight of a bumblebee and its wing area into account, and assuming an airspeed of a few meters per second, the wings wouldn’t produce enough lift to keep the bee up and buzzing about. 

A bumblebee in flight. The white circular arrows
indicate where the leading edge of the wings create
a vortex which produces additional lift.

  It’s true that if an airplane were built with the same proportions, it would never get off the ground, but bees aren’t like airplanes. As a bee takes flight, it creates an effect known as dynamic stall, which induces a large vortex over the leading edge of its wings. This vortex creates a low pressure region above the wing, which briefly creates several times the lift of a normal airfoil, sucking the wing up and giving the bee the additional lift it needs to buzz around. It’s just like when you stir creamer in your coffee with a teaspoon—the coffee swirls around the edge of the spoon. If you move the spoon quickly, you can actually see a depression at the center of the vortex and feel the tug caused by the lower pressure. 
  Bees beat their wings about 200 times per second. Their thorax muscles don’t expand and contract so much as vibrate, like a rubber band. A nerve impulse comes along and plucks the muscle like a guitar string. This vibrates the wing up and down a few times until the next impulse comes along. The bee has its wing roots embedded in a special block of elastic material to help this. 
  The flight of the bumblebee is quite inefficient in that its wings are not coordinated—left and right wings flap independently and sets the bumblebee apart from most other creatures of flight. Bumblebees have adopted a brute force approach to flight powered by its massive thorax. This approach could have evolved to make bumblebees more maneuverable in the air to transport nectar and pollen back to the hive.

Easter Island

Six of the 15 Ahu Tongariki Moais, the largest 

grouping on Easter Island.

Easter Island is the southeastern most of the Polynesian Islands and the most remote. It got its name because Dutch explorers landed there on Easter Sunday, 1722. Local inhabitants of the island call it by the Polynesian name Rapa Nui. Easter Island is famous for its 887 stone monuments, called moai, which give the island a supernatural quality. These monolithic human figures are finely crafted and reminiscent of Incan stonework, yet they were carved between the years 1250 and 1500 AD which predates the Incans. Almost half are still at the main moai quarry, but hundreds were moved from there and set on stone platforms around the perimeter of the island. The moai have disproportionately large heads which represent the faces of deified ancestors. The statues faced inland overlooking their tribes, but most were toppled during conflicts between clans. The production and transportation of these statues is quite a remarkable feat, considering some reach a height of nearly 10 meters and weigh more than 75 tons.

   Anthropologists know that Easter Island was once heavily populated, yet no one is certain about what happened to these people. One recent theory is that overpopulation precipitated an ecological catastrophe which caused natural resources to become depleted. Research suggests there were millions of palm trees on Easter Island but they disappeared sometime before the arrival of European explorers. Early explorers also brought rats to the island which may have prevented the regrowth of these trees by eating the palm nut seeds. As the island was deforested, soil erosion made it difficult to sustain vegetation. A problem that continues even now.

   While ecological problems did play a large part in reducing the population from a high of 15,000 to about 3,000 inhabitants, the final blow to these people came in the form of slave trade and disease. Peruvian slave traders made several trips to the Island during the 1860s, capturing about half of the remaining inhabitants. Forced to work as laborers and servants, many died soon after they were taken from their home. Slave traders, whalers and missionaries also brought small pox and tuberculosis. By the end of the decade only 111 natives remained on the island and most of their cultural history was lost. 

Some of the more iconic rongorongo glyphs and 

what they might have meant.

   Also lost was the ability to read and write the rongorongo script, a system of glyphs discovered on Easter Island and the only Polynesian writing to have ever been found. The last few people that knew how to read and write it were among those captured and enslaved. While there have been many attempts to decipher this writing, none have been successful. How unfortunate that we cannot read one of the very few independent inventions of writing in human history and which would likely reveal many secrets of Easter Island.

1) Easter Island got its name from Portuguese explorers who discovered it in 1722.

2) The stone monuments of Easter Island, or moai, represented _____________________.

a) deified ancestors  b) Incan gods  c) Dutch explorers  d) Polynesian gods

3) True or false: Native inhabitants of Easter Island fell victim to disease, enslavement and loss of natural resources.

4) Trees could not regrow on the island because of ________.

a) harsh climate  b) disease  c) rats  d) overharvesting

5) Rongorongo is the only form of Polynesian ______________.

Mysteries of Mercury

Artist’s rendering of the MESSENGER spacecraft 

orbiting Mercury.

NASA’s MESSENGER probe successfully began orbiting Mercury earlier this month, and as a result some of the enduring mysteries associated with this planet may be solved in the near future. Insights gained by this mission could shed light on how planets were formed in our solar system. MESSENGER stands for MErcury Surface, Space ENvironment, GEochemistry and Ranging, which is NASA’s clever way to tie the mission to Mercury with the Roman messenger of the gods. Launched over six years ago, MESSENGER’s trip has included 15 orbits around the sun and flybys of Earth, Venus and Mercury in order to slingshot into position where, after a 15 minute burn of its main thruster to slow down, it finally settled into orbit on March 18, 2011. 

   Mariner 10, the first and only other probe to approach Mercury, made three flybys from 1974 to 1975. Mariner was able to image 45% of the planet. It also unexpectedly discover that Mercury has a magnetic field. It is thought that planets generate magnetic fields because they have molten iron cores that spin quickly, but Mercury only rotates once every 59 day. Plus it’s so small that its core should have cooled off long ago. MESSENGER will analyze Mercury’s magnetic field which should yield insights about Mercury’s core. One thought is that Mercury’s core is shrinking as it slowly freezes. The planet’s surface is marked with mile-high cliffs that stretch for hundreds of miles and suggest that the planet is indeed shrinking. MESSENGER will look for more such evidence.

   Another mystery regarding Mercury’s core: why is it so large for such a small planet? Scientists believe that its iron core takes up about three fourths of the planets diameter, which is roughly twice that of Earth. Perhaps impacts over billions of years have stripped away Mercury’s surface, leaving only the inner mantle and core untouched. MESSENGER will analyze the planet’s geology which should shed some light on how it evolved. 

   Temperatures on Mercury reach a blistering 425° C, yet at the poles there are deep craters that are permanently shielded from sunlight, and there might be ice deposits hidden away. If so, MESSENGER will be able to detect such an unlikely source of water, not unlike finding an ice cube in an oven. The probe will collect data for one year, and I will be publishing updates as this data gets interpreted and shared with the public.

1) True or false: Mercury has been thoroughly explored.

2) It is thought that planets need _______ to have a magnetic field.

a) a solid iron core  b) a liquid iron core  c) a rapidly rotating iron core  d) both b) and c)

3) True or false: MESSENGER has detected ice at Mercury’s poles

4) Mile-high cliffs on Mercury are thought to be evidence that the planet is ______________.

a) shrinking  b) very hot  c) small  d) both b) and c)

5) The first probe to visit Mercury was ________________.

Science and Religion

Nature’s Ultimate Commuter

The Arctic tern is an elegant flyer performing an annual 

long-distance migration between the Arctic and the 

Antarctica. Photo: Carsten Egevang/arc-pic.com.

The Arctic tern is a medium-sized seabird, white with a black head and a bright orange beak. It has long, slender wings, and is an elegant flyer, but its legs are short which makes it clumsy on the ground. Its diet consists of small fish, insects and invertebrates. Arctic terns have been known to live 30 years or longer and their current population is estimated at about one million.

   The Arctic tern is nature’s ultimate commuter. This seabird migrates from its northern breeding grounds in Iceland and Greenland to the Southern Ocean around Antarctica and back, seeing two summers each year. This circumpolar trip of about 70,000 km is the longest yearly migration in the animal kingdom. Over the course of its lifetime, the Arctic tern flies a distance six times greater than the distance from the Earth to the Moon. Starting its trip in August, it pauses for a month in the mid-Atlantic Ocean where it fuels up on a rich supply of fish before continuing on to its winter habitat in Antarctica, arriving in December. In spring it returns north to Iceland and Greenland to nest. Once it has nested it starts out on another long southern migration.

   While flying long distance, the Arctic tern is able to put half of its brain to sleep while the other half remains alert and functioning. This is call unihemispheric sleep—the bird will actually sleep with one eye open and half of its brain awake, and it is able to use this ability at will.

   Arctic terns live together in colonies of about 50 birds. The male tern will court a female by taking a small fish in its bill and making a low pass over the female on the ground. If successful in attracting her attention, she will join him in this “fish flight” and they will soon mate. Both parents help incubate the eggs which hatch about 23 days after being laid. Chicks will leave the nest and hide from predators in nearby vegetation. The parents catch small fish for the hatchlings until they can feed themselves, but in recent years up to 90 percent of the tern chicks have died from hunger when food sources are not plentiful.

   Arctic terns are not fond of swimming and will do everything possible to stay out of the water. They hardly ever land. Most of the time they eat while flying, either swooping down to catch their fish, or catching insects on the wing.

The Arctic tern’s migration patterns, from the breeding sites in Greenland 

and Iceland to the winter grounds at Antarctica. The southbound migration 

is indicated by yellow lines with a month-long pause in the North Atlantic 

(small circle) before continuing to Antarctica (large circle). In spring, the 

northbound migration indicated by the white line is more than twice as fast.

1) True or false: The Arctic tern sees more sunlight in a year than any other creature on Earth.

2) A migration that includes both the Arctic and Antarctic regions is known as __________.

3) True or false: Arctic terns, while clumsy on land are excellent swimmers.

4) “Fish flight” refers to the Arctic terns’ _____________.

a) ability to catch fish during flight  b) mating ritual  c) migration  d) both a) and c).

5) The ability of terns to sleep with one eye open and half of their brain awake is called ______________________  sleep.

Why Dark Matter Matters

Surprisingly, only about one sixth of all the matter in the universe can be accounted for through observation. For example, when astronomers measure the hot gas clouds in the outer portion of galaxies they can calculate how much gravity that galaxy must have in order to keep the gas from escaping. Comparing that with how much matter is actually observed in the galaxy they come up short by a factor of five or six. This undetectable mass is called dark matter. Some of this dark matter is in the form of very dim dwarf stars, cold gas clouds, unlit planets or even black holes. These are called MACHOs (MAssive Compact Halo Objects). The halo refers to the outer part of a galaxy that extends beyond what is visible. Think of a large planet like Jupiter, for example. It can only be seen because it reflects the light of the Sun. If Jupiter was set adrift through interstellar space it would only be indirectly observable by its gravitational effect. When a MACHO passes in front of a background star, its gravity bends the starlight around it which causes the star to briefly shine much brighter. This focusing of the star’s light is called gravitational lensing. Astronomers have searched the skies for evidence of MACHOs by gravitational lensing, and it does not account sufficiently for the missing mass.

   Another type of dark matter consists of theoretical particles which are yet to be detected. They are called WIMPs (Weakly Interacting Massive Particles), and astrophysicists are hoping to bridge the missing matter gap by finding evidence of their existence. Because WIMPs only interact through gravitational and weak forces, they are quite difficult to detect. Billions of them could pass through the Earth every second without leaving a trace. There are many experiments currently underway to detect WIMPs either directly or indirectly.

According to the Big Crunch theory, the universe 

will end in an infinitely dense singularity.

   There is much we don’t know about dark matter, yet the eventual fate of the universe depends on how much of it there is. We know that the universe has been expanding since the Big Bang, but will it continue to do so forever? That depends on its total mass which counteracts the expansion through gravity. With enough dark matter it will eventually collapse back in a Big Crunch. Otherwise, our universe will keep expanding forever and likely end in a Big Freeze. But don’t worry too much—either fate is at least 15 billion years away.

1) True or false: Most of the matter in the universe is dark matter.

2) MACHOs can be detected by their _________________.

a) reflection  b) magnetic field  c) spectral signature  d) gravitational effects

3) True or false: MACHOs are theoretical particles.

4) WIMP stands for __________.

a) Weakly Involved Massive Planets  b) Wandering Interactive Micro Particles c) Weakly Interacting Massive Particles  d) Wandering Irradiated Micro Planets

5) Two eventual fates of the universe are ________________.