Earth scientists turning up the heat
Two new studies are increasing our understanding of the planet we live on and the forces that shape it…and it’s only proper for them to be from opposite ends of the world, as well.
In Massachusetts, a trio of geophysicists report in a letter to Nature that they have imaged a sharply-defined boundary between Earth’s rigid crust and the molten layer it rests upon. The nature of this “lithosphere-asthenosphere boundary” had previously been poorly understood, thought its existence has been widely accepted. The new data, obtained from recording sound waves traveling through the ground in eastern North America, shows a sharp gradient between the two layers that can most readily be explained by the presence of water or partly-molten rock at the boundary in addition to the steep increase in temperature.
And in Japan, researchers at the KamLAND subatomic particle detector are making great strides in understanding the origin of Earth’s magnetic field. They have succeeded in counting the number of antineutrinos (small particles produced during atomic decay) streaming from the planet’s core – 16.2 million per square centimeter per second, to be exact – and thus providing an exact measurement of its natural radioactivity. The nuclear decay responsible for these antineutrinos partly contributes to the vast amount of heat driving convection currents that churn Earth’s molten iron outer core and produce the magnetic field; with this measurement, we’ll now be able to determine the true extent of radioactivity’s role.
All in all, it’s been a pretty hot news week in earth science.
The lubricated hurricane
According to a new study, without sea spray, hurricane-force winds wouldn’t exist. The spray kicked up by large waves and falling raindrops lubricates the air above the ocean, which decreases the amount of turbulence. This lack of turbulence allows the winds to increase in force until they become a hurricane. Researchers estimate that wind speeds would peak around 25mph if there were turbulence to sap the budding hurricane’s energy.
The equations, when applied to a cloud of water droplets sandwiched between flowing air and water, indicate that large water droplets thrown up by cresting waves in rough seas inhibit the turbulence in the air over the ocean. Without this turbulence to drain energy from the swirling winds, winds can build to tremendous speeds. Without turbulence, friction between the air and water would be reduced by a factor of 1,000, Chorin said, sometimes allowing winds to rise to speeds eight times greater than would be the case with turbulence.
The turbulent vortices in the air are suppressed by the droplets when they rain back into the sea, somewhat like “combing unruly hair,” Chorin said. These droplets are about 20 microns across (8 ten-thousandths of an inch) or larger.
The smaller the droplets, the less ability they have to suppress the turbulence, he said, which suggests one way to calm hurricanes.
Not as crazy as it might sound at first, Chorin points to ancient times when sailors used to carry oil to pour on the ocean to help calm the waves, which isn’t superstition as it turns out. (I would question its effectiveness, though. How much oil would you need to calm a storm on the Mediterranean or Aegean, even in just a small area?)
Whereas [Sir M. James] Lighthill thought that evaporation of the droplets cooled the atmosphere and led to accelerated winds, Chorin, Barenblatt and Prostokishin have showed that more important is the reduction of turbulence by falling droplets. Nevertheless, they note that evaporative cooling also serves to reduce turbulence and thus allow winds to build.
Somehow I think it’s only a matter of time before someone trademarks “Hurricane” brand sex jelly.
The military’s new “Active Denial System”
Where “Active Denial System” is a nice way of saying “long-distance microwave oven.”
Some people were actually crazy enough to volunteer to stand in front of the US military’s new Active Denial System (ADS) microwave. The ADS is part of the Petagon’s new “less-lethal” weapons program — I wonder if “less-lethal” is like saying “a little pregnant?” — anyway, the weapon fires a 95GHz microwave beam at rioters, intruders, obstreperous children, bags of unpopped popcorn, whatever. This beam is supposed to cause pain but no injury. The weapon was tested in 2003 and 2004, but little was heard about the tests afterwards, until Edward Hammond requested the documents about the tests under the Freedom of Information Act.
Several tests were conducted, two to measure pain tolerance levels and one to determine its efficacy in driving away simulated rioters or intruders. The weapon created pain within two seconds of its activation, and the pain levels become intolerable within five seconds. The idea is that the pain will force the rioters or what have you to disperse, which seems like a good idea. After all, I don’t know many rioters interested in suntanning while they’re rioting, no matter how convenient it might seem.
There are some big problems with such a system, however. The main one is what happens if someone is unable to get out of the path of the beam. Would the weapon cut out to prevent overexposure? Living in downtown Boston, near Fenway Park, I “attended” the Red Sox riots last year after the Sox beat the Yankees, and then again when they won the World Series. (No, I wasn’t a rioter; I was a spectator.) Anyway, in a situation like that, I was lucky to be able to move at all. In some cases, it took me a good five minutes just to move 100 feet. Now, if the police had turned on their lovely ADS guns in an attempt to move the crowd, there would have been injuries: tramplings from people trying to avoid the beam, and burns on people unable to do so. Now the military is considering using a vehicle-mounted ADS in Iraq and other places as a means, again, of crowd control. This strikes me as a really bad idea.
During the experiments, the volunteers threw up their arms when they were hit with the beam, and were given a 15 second “cooling off” period before they were targeted again. In one test, a volunteer ended up with burns because the beam was accidentally used on the wrong power setting. Oopsie.
Hmm. I wonder if I could explode a potato at 200 yards?
Shuttle fleet grounded once again
The Associated Press is reporting that NASA has grounded further shuttle launches pending an investigation of how foam insulation once again broke off from Discovery’s fuel tank during lift-off. Also of concern is a 1.5-inch long piece of tile lost from Discovery’s underbelly, near the landing gear. Although review of video taken during launch and docking with the ISS and scans conducted with a laser-tipped crane onboard has revealed no damage that may hinder the current mission’s return to Earth, NASA’s schedule is to be put on hold until the problems can be resolved.
Shuttle program manager Bill Parsons spoke to reporters Wednesday evening, describing the matter at hand. He said:
‘Until we’re ready, we won’t go fly again. I don’t know when that might be, so I’ll just state that right up front. We’re just in the beginning of this process of understanding.’
One can only hope that this understanding will soon be attained to speed our safe return to space.
The need for (computing) speed
The advent of massively parallel computing gave scientists in many fields the ability to finally solve problems once considered intractable and run simulations of experiments that would be difficult, if not impossible, in the laboratory. Now, scientists in Japan plan to further increase the capabilities of this technology with a new supercomputer that promises to be faster than today’s 500 most powerful systems all put together.
The computer, which will be built by the collaborative efforts of NEC and Hitachi among others, is predicted to have a top speed of 10 petaflops, or 10^16 calculations per second (and cost ~$800 million to build); it would take roughly a billion desktop computers to do the same. IBM’s Blue Gene/L, the current titleholder, can only perform 1.4 x 10^14 calculations per second for comparison.
Most intriguing about this new supercomputer is its anticipated architecture. Today’s top systems (Blue Gene/L included) already use specially designed chips to enable faster memory access and other optimizations; however, the proposed design might feature an unprecedented hybridization of several different specialized processors in one machine. Such assembling of a variety of chips, produced to each perform a single calculation at incredible rates, has the potential to lend great bursts of speed to supercomputing’s very specific applications (e.g.: climate studies, protein folding simulations).
More pressing than questions of global warming and drug interactions, though, is… how can I get one of these?
Diabetes, stem cells, and osteoporosis
It’s a relatively well-known fact that people grow fat cells in their bone marrow as they age. (If you didn’t know this, you’re not alone because I didn’t either.) As a child, one starts out with almost no fat in the bone marrow. As one ages, the bone marrow slowly turns to fat; at the age of 30, approximately half of one’s bone marrow is fat. For a long time, it was just assumed that this was part of the aging process. More recently, however, scientists have found a stem cell in the bone marrow that can turn into marrow or fat depending on the signal it receives. Those individuals with osteoporosis have much higher levels of fat in their marrow than do those without the disease. Those who take steroids to suppress the immune system also have much higher levels of fat.
What these levels of fat in the marrow means is still a matter of speculation. Even young, healthy people have fat in their marrow. Doctors think that perhaps the fat is there to act as an internal cushion of sorts, since hollow bone by itself is relatively brittle and prone to breakage. So while a knee-jerk thought might be that high levels of fat mean weak bones, this isn’t necessarily the case. Osteoporosis, which is the disease of porous and weak bones, comes as a result of loss of bone density, not high levels of fat; and it could be that increased fat levels in the marrow is one way of the body coping with this bone weakness. That’s my speculation, anyway, no one knows for sure. There’s also some thought that the fat forms as a means of storing energy, like other fat deposits found in the body.
Medical ramifications and speculation aside, what’s really interesting about all this is how the fat can be manipulated. If stem cells are placed in a petri dish and allowed to grow, they don’t remain undifferentiated stem cells for very long. They begin to differentiate into what they’re programmed to become, under the influence of the “biochemical soup” (their term, not mine) that they’re growing in. In the case of the bone marrow stem cells, adding steroid hormones causes them to turn to fat, but adding vitamin D3 caused them to turn into bone.
What does all this have to do with diabetes? Well, one of the drugs used for Type II diabetes, rosiglitazone — better known as Avandia — produced fattier bone marrow in tests on lab rats. Not a just a small amount of fat in the bones, but three times the amount as the control rats. The standard disclaimer, of course, being that thiazolidinediones — like Avandia and Actos — might not have the same result in humans since the physiologies of rats and humans are quite dissimilar. More testing needs to be done; it is not known if these drugs cause increased levels of marrow fat in humans.
And fat can be turned into bone as well. Fat taken from liposuction patients can be turned into bone by adding vitamin D, dexamethasone, and a few other things. Dexamethasone is a corticosteroid, which I find strange, because adding corticosteroids caused higher levels of fat in the marrow in previous in vitro tests , rather than promoting bone density as it seems to be doing here. Even stranger, however, is the fact that fat will turn into bone if it’s not stopped. There is a gene in the human body that must be suppressed, otherwise it will randomly turn fat into bone. This rare genetic disorder is called progressive osseous heteroplasia. Using this knowledge, researchers hope to find a drug that will cause only bone marrow fat to turn to bone. Somehow the possible side effects listed on that medication seem like they would dissuade anyone from using it: “Warning: Use of this medication may cause bone formation (ossification) in strange places. If you find bones growing where they shouldn’t, please contact your doctor or pharmacist immediately.”
Amazon Deforestation Accelerating
The BBC is reporting that the Amazon rainforest is shrinking at an increasing rate. Twenty six thousand square kilometers were lost last year in Brazil alone, mostly to slash-and-burn deforesting, which amounts to about 0.4% of the total seven million square kilometers. While that may not sound like much, keep in mind that at that rate the rainforest will be completely gone in about 200 years, and with an acceleration that timespan will be even smaller.
It may seem that there is still quite a long time to solve the problem. There are ancillary problems, however. Islandization is the splitting up of once-connected geographical regions to produce smaller, isolated ecosystems. This can be a death blow to larger animals which require large roaming areas such as the jaguars of the Amazon. So while the total acreage is still appreciable, the biological impact can be simultaneously quite large.
The Amazon is one of a handful of biodiversity “hotspots” in the world. It houses approximately 20% of all birdlife on planet Earth, as well as 75,000 species of trees (according to Wikipedia). While many argue that investment in the environment is hardly worth the effort, a small investment in these ecological “hotspots” has a large rate of return. There are useful plant and animal species that are in extremely high density in the Amazon, so that environmental protection can be more effective than nearly any other location on the planet.
Edward O. Wilson, a Harvard myrmecologist has written a book entitled The Future of Life that delves into just such subjects. He takes a pragmatic viewpoint and concludes that humanity will realistically fundamentally change the biosphere, but ecological protection spearheaded by international NGO’s such as the The Nature Conservancy in a few key regions of the globe can have a lasting impact by preserving biodiversity.