Since that tragic day of March 11, 2011 when an enormous earthquake and horrific tsunami struck the northeastern side of Japan, we have been inundated by media reports on the ongoing attempts to bring the nuclear plant into a stable condition. The technical challenge is enormous but the task is simple--keep the core and the spent fuel covered with water. While designed to withstand earthquakes of magnitude 7, the site felt a magnitude 9. While designed to withstand a tsunami of approximately 22 feet, the site was swept by a wave of 30 feet. This wall of water wiped out everything in its path; the visual devastation witnessed by the world was unimaginable. This same wave slammed the nuclear plant sites of Daiichi and Daini where 10 reactors stood bracing for the onslaught. According to reports, the plants withstood the earthquake but the wave was too much for the auxiliary equipment needed to supply power and electricity to the emergency cooling systems designed to protect the core at Daiichi. The major structures survived but what was lost was the ability to cool the core and the spent fuel pools for four of the units.

In the wake of this terrible event--we cannot call it an accident, since it was a natural disaster that needed to be managed--it has been difficult to separate media reports rooted in solid science from those peddling unfounded conjecture. Having followed the event closely, it was difficult to get reliable status reports as to what was happening and why. The Tokyo Electric Power Company (TEPCO) itself had difficulty for the same reasons the public did--electricity was lost, roads and highways were destroyed, communications were difficult and unreliable, and understanding the magnitude of the damage at 10 stations required time. What information was made available by the government, Japan's Nuclear and Industrial Safety Agency and TEPCO was limited and incomplete, encouraging speculation as to what was really happening. Given whatever information was available, trained nuclear engineers could begin to assemble a picture of the events based on their technical understanding of nuclear systems and fuel behavior under various possible scenarios for these types of reactors. Even so, most of the discussion was conjecture since we did not know exactly what happened.

There was a group of "experts" that was often quoted and seen on television who would, without hesitation or qualification, give the media what they wanted to hear: scenarios of disaster, fear and unbounded "China Syndrome" core meltdown stories. When many of these faces began appearing, I did a background check on some. One often sought-after "expert" in nuclear engineering was a psychology undergraduate major with a Ph.D. in political science from a prestigious university. Another group was from an international peace organization. We also have physics professors willing to speak to nuclear engineering issues, not recognizing that quantum mechanics has little to do with net positive suction head. It is through these mouths, written words, and faces that the story of Fukushima is being told to a public that really wants and needs to understand what is going on. If only our national media would do some background checks on the people that they call upon as experts before they put them on television or quote them to inform us, we would be so much better off. Instead, they seem to find people who fit their "story line."

The March 11, 2011 earthquake and tsunami caused massive destruction in Japan. Six nuclear reactors at the Fukushima Dai'ichi power plant became a significant cause for concern in the aftermath as the plant lost power and reactor cores started melting down. Both the earthquake and tsunami were much larger than predicted and caught everyone, including nuclear power plant designers, by surprise. How could the geologists who predicted these events have been so wrong?

The reactors had been designed to withstand an earthquake of magnitude 7.9. After all, in the entire 20th century, the maximum earthquake experienced in the region was magnitude 7.8. The Tohoku earthquake on March 11 was magnitude 9.0, releasing 45 times more energy than the reactor was designed to withstand. The tsunami wave height was also significantly underestimated. The Fukushima plant was designed to withstand a tsunami of 5.7 m height. Recent estimates put the Tohoku tsunami wave height at 14 m.

In the nuclear field, policy makers often demand predictions about Earth behavior: What's the largest earthquake that will occur at the site of a nuclear power plant? Will the nearby fault move? Is this a reasonably safe location to site a geologic repository for high- level radioactive waste? The advantage of these predictions is that they provide simple and straightforward parameters for policy decision-making. The disadvantage, as we now know, is that they can't be made with the necessary accuracy.

As part of the NOVA team filming Japan's Killer Quake, I arrived in Japan two days after the March 11 earthquake and tsunami. I flew by helicopter over coastlines damaged by the event, consulted with colleagues at Japan's Earthquake Research Institute, and generally tried to gain a preliminary understanding of the nature and impact of the devastating 9.0 earthquake.

My first reactions on arrival in Tokyo were of admiration for the seismologists and earthquake engineering community of Japan. There was almost zero damage to the buildings of Tokyo, and, in fact, little shaking damage throughout much of Honshu, the largest island of Japan. This surely must be considered a success story given the enormity of the earthquake. It was the tsunami that did most of the damage, which I'll touch on below.

Here, illustrated with diagrams I have put together, are some initial thoughts, together with a brief discussion of potential dangers awaiting Japan as well as the U.S.:

Foreshocks and aftershocks



As this graph shows, several foreshocks (in red) occurred near the epicenter of the mainshock, but, regrettably, these were not recognized at the time as precursory to the mainshock sequence. As if the monster mainshock of March 11 were not enough of a scare, the Japanese people have endured numerous aftershocks, some of them larger than the Haiti earthquake. They continue to be felt now, two weeks after the mainshock.

It is the incomprehensible scale of the tragedy that silences you. There's the physical scale: A car perched on the roof of a three-story building in Minami Sanriku, or the 200-ton tug Kazumaru No. 1, swept 1,500 feet inland in the port of Ofunato, smashing every house in its path to splintered pulp.

The Kazumaru No. 1 tugboat, where the March 11 tsunami left it. Image courtesy WGBH.

But there's also the scale of the human tragedy. Rikuzentakata must once have been a stunningly beautiful coastal town. If you stand in the bay and look up at the mountains, the view is lovely, the mountains still and peaceful. But lower your eyes and the scene is of awful devastation. Where once there was a town of over 20,000, now there is a blasted mudflat.

I followed a group of perhaps 50 soldiers from the Japanese Self-Defense Forces, armed with bamboo canes, onto the mud. They formed a long line, waiting for the order, then set off on a careful yard-by-yard search.

As heroic workers and soldiers strive to save stricken Japan from a new horror--radioactive fallout--some truths known for 40 years bear repeating.

An earthquake-and-tsunami zone crowded with 127 million people is an unwise place for 54 reactors. The 1960s design of five Fukushima-I reactors has the smallest safety margin and probably can't contain 90% of meltdowns. The U.S. has 6 identical and 17 very similar plants.

Every currently operating light-water reactor, if deprived of power and cooling water, can melt down. Fukushima had eight-hour battery reserves, but fuel has melted in three reactors. Most U.S. reactors get in trouble after four hours. Some have had shorter blackouts. Much longer ones could happen.

Overheated fuel risks hydrogen or steam explosions that damage equipment and contaminate the whole site--so clustering many reactors together (to save money) can make failure at one reactor cascade to the rest.

Nuclear power is uniquely unforgiving: as Swedish Nobel physicist Hannes Alfvén said, "No acts of God can be permitted." Fallible people have created its half-century history of a few calamities, a steady stream of worrying incidents, and many near-misses. America has been lucky so far. Had Three Mile Island's containment dome not been built double-strength because it was under an airport landing path, it may not have withstood the 1979 accident's hydrogen explosion. In 2002, Ohio's Davis-Besse reactor was luckily caught just before its massive pressure-vessel lid rusted through.

Regulators haven't resolved these or other key safety issues, such as terrorist threats to reactors, lest they disrupt a powerful industry. U.S. regulation is not clearly better than Japanese regulation, nor more transparent: industry-friendly rules bar the American public from meaningful participation. Many presidents' nuclear boosterism also discourages inquiry and dissent.

Late last week, I was doing background research for a possible story on the future of nuclear energy. Has global warming tipped the risk-benefit scales in nuclear's favor? Can any of the next-generation reactor designs claim to be truly accident-proof--and terrorist-proof? Are we any closer to solving the waste problem?

The Fukushima Daiichi power plant, photographed in 2002. Via the Wikimedia Commons.

This week, those questions feel a lot less hypothetical. The earthquake and tsunami that struck Japan on Friday damaged multiple reactors at the Fukushima Daiichi Nuclear Power Station, 150 miles from Tokyo; since then, explosions and fires at the plant have released radiation to the atmosphere. With cooling pumps out of order, workers are struggling to keep the reactors cool using seawater, which requires venting radioactive steam. Tens of thousands of people living nearby the plant have been evacuated, and more than one hundred thousand in a larger danger zone are being asked to confine themselves to their homes. As the New York Times reported, Japanese Prime Minister Naoto Kan "pleaded for calm, but warned that radiation had already spread from the crippled reactors and there was 'a very high risk' of further leakage."

Workers are attempting to bring the reactors under control, and to prevent spent fuel rods, which are kept submerged in water, from overheating and deepening the crisis. We don't know yet what toll this emergency will take on the people of Japan and on the environment. But policymakers are even now beginning to gauge how this nuclear crisis may affect the fate of nuclear energy in the United States, where the looming threat of global warming has elevated nuclear to the "lesser evil" in the minds of many, including some of its former foes.

For the first time in decades, new nuclear plants are in the works here in the U.S., with the blessing of President Obama and Energy Secretary Steven Chu. (Hear Steven Chu talk about nuclear power.) Though Slate's David Weigel reported on Tuesday that the crisis in Japan has not weakened Washington's support for nuclear, some top House Democrats are calling for an investigation and hearings on the safety of the United States' nuclear plants. Meanwhile, Switzerland is suspending plans for new plants, and Germany has put a temporary hold on extensions of current plants, according to the New York Times.

What can we learn from what's happening in Japan? Is it possible to compare the risks and benefits of nuclear energy with the risks and benefits of fossil fuels? Can we build a truly accident-proof reactor? In the coming days and weeks, we'll be using this space to bring you opinions on these questions from a number of nuclear and environmental experts. In the meantime, we invite you to share your thoughts on the crisis in Japan and what it means for the future of nuclear energy here in the United States and around the world.

Read more articles from Inside NOVA's "Nuclear After Japan" series.

Take a creature that's just over three feet tall, with a brain the size of a grapefruit, oversized clown-shoe feet, and the ability to craft and hunt with stone tools. Is it another species? A sick or genetically defective human? Scientists have been arguing about this since the creature--dubbed Homo floresiensis, or "hobbit" to its friends--was first discovered in a cave on the Indonesian island of Flores back in 2003.

When NOVA's Alien from Earth premiered in 2008, the jury was still out. In one camp were scientists who believed the hobbit was a previously undiscovered species, a new branch on the tree of human evolution. In the other camp were critics who argued that the hobbit's diminutive skull was evidence of microcephaly, a disorder that causes the head and brain to develop abnormally. That would explain why the hobbits were still alive and kicking a mere 18,000 years ago, when modern humans were already living in Australia and more primitive hominids had long-since disappeared.

Since that premiere, though, a flurry of new evidence has accumulated suggesting that the hobbit really is a new species. With a rebroadcast of Alien from Earth coming up this week on some PBS stations (please check your local listings to find out when it will air near you, or watch it streaming online), we've compiled some of the latest discoveries about the hobbits and their history.

First, the hobbits' arrival on Flores has been pushed back by nearly 300,000 years. When Alien from Earth first aired, the oldest evidence of the hobbits was a cache of stone tools dated to about 700,000 years ago. But in 2010, scientists led by Australian archaeologist Adam Brumm announced that they'd discovered more stone artifacts, this time buried beneath an ash layer deposited by a volcano that erupted a million years ago; ergo, someone was making tools on Flores before the volcano went off.

Second, a close examination of hobbit foot bones revealed that the hobbits walked upright on disproportionately large feet. (Their feet measured seven and a half inches long.) Those big feet suggest that the hobbits' ancestry goes back to an even more primitive species than was first thought.

How could a healthy animal end up with such a scrawny brain? Creatures on isolated islands are known to balloon up and shrink down over many generations, two phenomena known as gigantism and dwarfism. In fact, Flores itself is home to funhouse-mirror creatures like giant storks, monster Komodo dragons, and pygmy elephants. Yet island dwarfs often end up with heads that are disproportionately large for their shrunken bodies, so many scientists doubted that this kind of island dwarfism could explain the hobbit's oddball proportions. But in 2009, scientists at London's Natural History Museum used skulls from two types of dwarf hippos (both now extinct) to create a new model for the scaling of brain size and body mass in dwarf species. Their model suggested that the hobbits could indeed be healthy island dwarfs.

But to know for sure whether the hobbit represents a new species, scientists would like to look at its DNA. It has been tried before, by teams from Germany and Australia, without success. Now, Christina Adler and her team at the Australian Centre for Ancient DNA are planning to give it another go, this time using a sample from a DNA-rich substance called cementum, which coats the roots of teeth.

Meanwhile, the Australian Research Council has funded more excavations on Flores. Archaeologists like Mike Morwood, one of the original discoverers of the hobbit bones, hope that these large-scale digs could turn up bones from hobbit ancestors one million years old--or even older.

Your brain really doesn't remember the things it sees very well. While it might capture certain aspects of the world, it mostly discards the information it processes. University of Illinois psychologist Daniel Simons (along with collaborator Daniel Levin of Vanderbilt University) has devised many experiments to show just how poor our visual cognition can be, which the NOVA scienceNOW team replicated in this video blog.

Curious as to how the other parts of your brain work?  NOVA scienceNOW shows you how magic, free falls, and mind controls devices are shaping the way we think about the brain.

Alex Liu is a former NOVA scienceNOW intern and recent NYU SHERP graduate who now lives in the San Francisco Bay Area. Visit his personal website and follow him on Twitter.

Imagine yourself standing on the shore of a river in eastern Australia, arms outstretched to avoid being nipped by the flailing, angry platypus you have suspended upside down by its tail. The scene is strange enough without considering the oddities of the animal you have captured: It has the fur of a mammal, the bill of a duck, and the tail of a beaver, and it lays eggs like a reptile. And it's venomous. The platypus is one of a very select group of mammals that produces venom, and it is giving scientists clues into how and why venom evolved across species.

Catch me if you can! By Stefan Kraft (GFDL or CC-BY-SA-3.0) via Wikimedia Commons.

Right now, not much is known about the contents of platypus venom. Part of the reason for this is that platypuses are somewhat tough to come by. They don't breed well in captivity, and concerns about disturbing them during mating season make them difficult to track down in the wild. Fortunately for us, field scientists like Tom Grant of the University of New South Wales regularly put themselves in the aforementioned strange scenarios on eastern Australian rivers. Grant and his colleagues lay nets in the water in hopes of trapping an animal, and when they have one, they grab it by its long tail and hold it upside down. Platypus venom spurs are located on the hind legs, so while one scientist holds the angry, dangling platypus by the tail as far away from himself as possible to avoid being stung, another holds a small pipette up to the spurs in hopes of extracting a little venom that can be stored and studied. The venom is strong enough to kill a dog and cause debilitating pain to a human. Just another day at the office.