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for December, 2009.
Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.
Greetings everyone and welcome to the last column of the year. I thought today we’d take a little trip through the animal file and see what we can find about the critters that share our world with us.
One critter I can definitely do without is the mosquito. Besides the fact that the mosquito is annoying and painful, it’s also a notorious spreader of disease. Quite frankly, I personally think we’d be better off without them. Here’s a sad little tale of economics and pests.
TAKING OUT THE STING
After searching for more than 50 years, scientists finally have discovered a number of new mosquito repellents that beat DEET, the gold standard for warding off the pesky insects. They sound like a dream come true. They repel mosquitoes for up to three times longer than DEET, the active ingredient in many of today’s insect repellents. They don’t have the unpleasant odor of DEET. And they don’t cause DEET’s sticky-skin sensation. But there’s a mosquito in the ointment: The odds appear to be stacked against any of the new repellents ever finding a place on store shelves.
Ulrich Bernier, Ph.D., the lead researcher for the repellent study, said that costly, time-consuming pre-market testing and approval is a hurdle that will delay the availability of the repellents, which were discovered last year.
Making the repellents commercially available takes significant investment in both money and time. The cost may be several hundred thousand dollars. Once it’s determined that the repellent works then there’s also a toxicological hazard evaluation involving numerous toxicological tests."
If the repellents continue to work well when tested in the laboratory on human skin, and if they pass the battery of toxicological tests, they still face a series of tests to prove their effectiveness against mosquitoes.
Bernier and his team discovered the repellents with what they say is the first successful application of a computer model using the molecular structures of more than 30,000 chemical compounds tested as repellents over the last 60 years. Using 11 known compounds, they synthesized 23 new ones. Of those, 10 gave about 40 days protection, compared to 17.5 days for DEET, when a soaked cloth was worn by a human volunteer. When applied to the skin, however, DEET lasts about five hours.
Bernier routinely participates in repellency studies, which involve about 500 mosquitoes trying to land on his arm and bite through a repellent-soaked cloth. If the mosquitoes don’t land, the researchers know the repellent is working. If they walk around on the cloth-covered-arm, they’re on the verge of being repelled. If they bite…then it’s on to the next repellent.
To search for the best repellents, the team devised software that recognized structural features of a chemical that would make it effective in keeping the bugs away. They trained it by feeding it the molecular structures of 150 known repellents. Based on this information, the program learned to identify the chemical traits of a good repellent without the chemists even having to know what those traits were. For example, the team checked out 2,000 variants of a compound found in black pepper that repels insects.
I hope that they get some funding to market these new repellants soon. I’d sure buy them!
Mosquitoes stay away from repellent-soaked cloth on the arm of researcher Ulrich Bernier. (Credit: Greg Allen, U.S. Department of Agriculture, Agricultural Research Service)
And now we move on to a tale of another of the least-loved animals on the planet.
YOU THINK WE’VE GOT PROBLEMS??
I’m having a little mini-invasion at my house. I’m surrounded by forest and a large family of brown tree snakes seems to have decided to call my house and my dog food theirs. We whip them around a mop handle and dump them in the freezer. No more blood, no more machete nicks on my stuff. It’s a humane way to die, not that I really care because brown tree snakes are aggressive and I’ve been bitten several times.
Brown tree snakes can get quite large, but they don’t hold a candle to the subjects of this story. The southern United States is being invaded by some of the biggest snakes on the planet.
A new report by the U.S. Geological Survey (USGS) tells all about the risks of nine non-native snake species including boa constrictors, anacondas and pythons. Two of the species have been documented as reproducing in the wild in South Florida where the Burmese python population is already reported to be in the tens of thousands.
Although the giant snakes don’t pose a great threat to humans, adults of the largest pythons have been known to attack and kill people in their native habitats. The snake most often associated with attacks on humans is the reticulated python, a native of Southeast Asia.
Although many of the giant snakes snake species may be confined to the deep South, others like Burmese pythons, northern and southern African pythons, boa constrictors and yellow anacondas put larger portions of the U.S. mainland at risk.
The USGS scientists who authored the report point out that native U.S. birds, mammals, and reptiles have never had to deal with huge predatory snakes before. Individuals of the largest three species reach lengths of more than 20 feet and upwards of 200 pounds. The reticulated python is the world’s longest snake, and the green anaconda is the heaviest snake. Both species have been found in the wild in South Florida, although breeding populations are not yet confirmed for either.
Breeding populations have been confirmed in South Florida for Burmese pythons and the boa constrictor, and there is strong evidence that the northern African python may have a breeding population in the wild as well.
Unfortunately these snakes mature early, produce large numbers of offspring, travel long distances, and have broad diets that allow them to eat most native birds and mammals. In addition, most of these snakes can inhabit a variety of habitats and are quite tolerant of urban or suburban areas. Boa constrictors and northern African pythons, for example, already live wild in the Miami metropolitan area.
The report notes that there are no controls adequate for eradicating an established population of giant snakes once they have spread over a large area. Making the task of eradication more difficult is that in the wild these snakes are extremely difficult to find since their camouflaged coloration enables them to blend in well with their surroundings.
Dr. Gordon Rodda, a herpetologist who lived on Guam, mentions us in the report. “We have a cautionary tale with the American island of Guam and the brown tree snake,” he says. “Within 40 years of its arrival, this invasive snake has decimated the island’s native wildlife: 10 of Guam’s 12 native forest birds, one of its two bat species, and about half of its native lizards are gone. The python introduction to Florida is so recent that the tally of ecological damage cannot yet be made.”
USGS researchers used the best available science to predict areas of the country most at risk of invasion by these giant snakes. Based on climate alone, many of the species would be limited to the warmest areas of the United States, including parts of Florida, extreme south Texas, Hawai
i, and America’s tropical islands, such as Puerto Rico, Guam, and other Pacific islands. For a few species, however, larger areas of the continental United States appear to exhibit suitable climatic conditions. For example, much of the southern U.S. climatic conditions are similar to those experienced by the Burmese python in its native range.
The Fish and Wildlife Service and the National Park Service will use the report to help them figure out what to do about the problem and how to prevent further colonization.
Researchers implant a radio transmitter in a 16-foot, 155-pound female Burmese python at the South Florida Research Center, Everglades National Park. Radio-tracking builds understanding of where pythons spend their time and therefore where they can be controlled in practice. Photo courtesy of Lori Oberhofer, National Park Service. (Credit: U.S. Geological Survey)
I once had a very good friend in Pete, the reticulated python. Despite her name, she was a female and she was a mascot for one of the units at U-tapao Air Base in Thailand. She had been captured on the flightline about five years before I got there and at that time, she was three feet long and weighed 30 pounds.
To keep Pete fed, the Thais who ran the café where she was housed ran a lottery. They put a chicken in the cage with Pete once a week and for a quarter, you could put in your guess of the day and time that Pete ate the chicken. The person who came the closest got the money, less the amount to buy the next week’s chicken.
Reticulated pythons don’t eat that often in the wild and when I left Thailand, Pete was 33 feet long and weighed 300 pounds. Most times, when I came to call, she would rear up her head until it was on the level of mine and we would chat. I never decided if she was just curious about the white lady, or viewed me as lunch. She was an impressive animal, but not one I’d want to meet in my back yard!
Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.
Greetings everyone! In light of the climate change talks going on right now, and the record snowfall happening on the east coast of the US and in Europe, I figured it was time to talk about everybody’s favorite subject: the weather. And despite that record snowfall, the news isn’t particularly good.
MONITORING THE ICE
In October, a NASA DC-8 airplane loaded with scientists and their instruments began low level passes over the Antarctic coastline where ice sheets are collapsing at a rate far faster than was predicted. The flights, dubbed Operation Ice Bridge, are an effort to determine what’s happening on and under the ice, in order to estimate future sea level rises.
Since 2003, laser measurements of ice surfaces from NASA’s ICESat satellite have shown that the ice caps in Greenland and West Antarctica are thinning and flowing quickly seaward. A report in the journal Nature based on data provided by ICESat showed that some parts of the Antarctica ice shelf have been sinking 27 feet a year. In 2002, one great glacial ice shelf jutting from land over the ocean on the Antarctic Peninsula simply disintegrated and floated away within days. ICESat reaches the end of its life soon, and another ice monitor won’t be launched until 2015. Until that happens, Operation Ice Bridge flights will continue and expand.
In addition to lasers, the plane will carry penetrating radar instruments that measure snow cover and the thickness of ice to bedrock, and a gravity-measuring system that will, for the first time, plot the geometry and depth of ocean waters under the ice shelves. The gravity study is very important because many scientists believe warm ocean currents may be the main force pulling the ice sheets seaward, melting the undersides of ice shelves and thus removing the buttresses that hold back the far greater ice masses on land.
Earlier this year, an icebreaker cruise sent an automated submarine to look under the region’s Pine Island Glacier, which has been moving forward rapidly in recent years. Its bed, where the ice contacts rock, is below sea level, and scientists are concerned about what would happen if seawater poured under the glacier.
The DC-8 is too big for any of the runways in Antarctica, and it will make the 11-hour round trip from Punta Arenas, Chile, with two-thirds of each trip spent getting to Antarctica. Once there, the plane will fly as low as 1,000 feet along sinuous glacial valleys that may test the nerves of both pilots and scientists. Some flights will also investigate the region’s open sea ice, which also seems to be disappearing.
"We learned how fast the ice sheets are changing from NASA satellites," said geophysicist Robin Bell, who is helping lead the project. "These flights are a unique opportunity to see through the ice, and address the question of why the ice sheets are changing."
"A remarkable change is happening on Earth, truly one of the biggest changes in environmental conditions since the end of the ice age," said Tom Wagner, cryosphere program scientist at NASA headquarters in Washington. "It’s not an easy thing to observe, let alone predict what might happen next. Studies like this one are key."
Antarctica’ Larsen Ice Shelf has deteriorated in recent years, and it’s one of the flight targets. (Credit: NASA)
So, if scientists are concerned that the warming seas are causing the coastal melting in both Greenland and Antarctica, what’s causing the warming seas? Despite those snowstorms happening right now, it could be that it’s warmer air temperatures. Read on.
DOES IT SEEM WARMER IN HERE TO YOU?
The combined land and ocean surface temperature for the entire Earth for September 2009 was the second warmest September on record, according to NOAA’s National Climatic Data Center whose records go back to 1880
NCDC scientists also reported that the average land surface temperature for September was the second warmest on record, behind 2005. Additionally, the global ocean surface temperature was tied for the fifth warmest on record for September.
The combined global land and ocean surface temperature was 1.12 degrees F above the 20th century average of 59.0 degrees F. Separately the global land surface temperature was 1.75 degrees F above the 20th century average of 53.6 degrees F.
Warmer-than-average temperatures engulfed most of the world’s land areas during the month. The greatest warmth occurred across Canada and the northern and western United States. There were also warmer than normal temperatures across Europe, most of Asia and Australia.
The worldwide ocean temperature tied with 2004 as the fifth warmest September on record, 0.90 degree F above the 20th century average of 61.1 degrees F. The near-Antarctic southern ocean and the Gulf of Alaska however, had cooler temperatures than average.
Sea ice coverage at the North Pole averaged 2.1 million square miles in September – the third lowest for any September since records began in 1979. The coverage was 23.8 percent below the 1979-2000 average, and the 13th consecutive September with below average Arctic sea ice extent.
Strangely enough, however, the sea ice in Antarctica was 2.2 percent above the 1979-2000 September average and was the third largest ice mass on record, behind 2006 and 2007.
Global surface temperature anomalies (degrees F) for the month of September 2009. (Credit: NOAA)
So . . . . we’ve got all these people monitoring the ice, but the ice is about as far away from us as it can get. I think most people are aware that a grave consequence of global warming will be the land loss for our neighbors here in the Pacific who live on low-lying atolls that are in danger of being completely submerged. But the crisis will hit long before that happens and is already in progress as rising sea levels are salt-contaminating vital food supplies like taro patches.
But are there other ways that global warming can affect us here? If you listen to the weather at all (and who doesn’t here?) you know all about the Intertropical Convergence Zone know familiarly to us as the ITCZ. It’s also called The Monsoon and the capital letters are a nod to just how important it is to us and to all of Asia and India. Well, guess what? Global warming isn’t just affecting the ice!
The rain band near the equator that determines the supply of freshwater to nearly a billion people throughout the tropics and subtropics has been creeping north for more than 300 years, probably because it’s a warmer world.
If the band continues to migrate at just less than a mile a year, which is the average for all the years it has been moving north, then some Pacific islands near the equator – even those that currently enjoy abundant rainfall – may be drier within decades a
nd starved of freshwater by mid-century or sooner.
"We’re talking about the most prominent rainfall feature on the planet, one that many people depend on as the source of their freshwater because there is no groundwater to speak of where they live," says Julian Sachs, associate professor of oceanography at the University of Washington. "In addition many other people who live in the tropics but farther afield from the Pacific could be affected because this band of rain shapes atmospheric circulation patterns throughout the world."
This band of rainfall is, of course, the Intertropical Convergence Zone. It’s created when trade winds from the northern and southern hemispheres collide north of the equator and it’s fueled by the heat of the tropical Sun. Rain clouds 30,000 feet thick in places proceed to dump as much as 13 feet of rain a year in some places. (Guam’s average is around 8 feet a year.) The ITCZ stretches across the Pacific and it’s generally between 3 degrees and 10 degrees north of the equator depending on the time of year. Scientists think that the ITCZ isn’t found in the southern hemisphere because of land mass distribution and the presence of the Andes mountains in South America.
Recent research provides surprising evidence that the ITCZ was originally much farther south and in fact was located on the equator several centuries ago during what’s called the Little Ice Age when Earth’s average temperatures were much cooler.
The scientists analyzed rainfall records in lake and lagoon sediments from four Pacific islands at or near the equator. One of the islands they studied, Washington Island, is about 5 degrees north of the equator. Today it is at the southern edge of the ITCZ and receives nearly 10 feet of rain each year. But drill cores reveal a very different Washington Island in the past: It was arid, especially during the Little Ice Age.
Among other things, the scientists looked for salt tolerant microbes in their sediment cores. On Washington Island they found that evidence in 400- to 1,000-year-old sediment underlying what is now a freshwater lake. Such organisms could only have thrived if there was much less rainfall than there is today. Additional evidence for rainfall changes was provided by hydrogen isotope differences that can only be explained by large changes in precipitation.
Sediment cores from Palau, which lies about 7 degrees north of the equator and in the heart of the modern convergence zone, also revealed that things were also much drier there during the Little Ice Age. In contrast, the researchers present evidence that the Galapagos Islands, which are very dry today were much wetter during the 1400-1700’s.
The researchers write, "The observations of dry climates on Washington Island and Palau and a wet climate in the Galapagos during the time of the Little Ice Age provide strong evidence for an ITCZ located south of Washington Island (5 degrees north) during that time and perhaps until the end of the eighteenth century."
If the zone at that time experienced seasonal variations of 7 degrees latitude, as it does today, then during some seasons it would have extended southward to at least the equator. This has been inferred previously from studies of the ITCZ on or near the continents, but the new data from the Pacific Ocean region is clearer because the feature is so easy to identify there.
The remarkable southward shift in the location of the ITCZ during the Little Ice Age can’t be explained away by changes in the distribution of continents and mountain ranges because they haven’t moved. But the Earth received less solar radiation during the Little Ice Age and that may have caused the shift.
If the ITCZ was 5 degrees south of its present position as recently as 1630, it must have migrated north at an average rate of about a mile a year. If that rate continues, the ITCZ will be more than 75 miles north of its current position by the latter part of this century.
So . . . what does this mean for us? Well, we may get drier. But if the ITCZ is moving north, it may mean that typhoon formation may move north as well, resulting in fewer typhoons, but also less rainfall. Global warming isn’t just happening at the poles!
The band of heavy precipitation the Intertropical Convergence Zone (ITCZ). The new findings are based on sediment cores from lakes and lagoons on Palau, Washington, Christmas and Galapagos islands. (Credit: Image courtesy of University of Washington)
Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.
Well, as I try to clean out the files, there are always lots of articles about the animal that absorbs the most research money; humans. There have been some interesting medical studies in the last few months so I thought I’d share a few.
As you have no doubt noticed, I’m attracted to the bizarre and this first story is certainly that. I’ve noticed that lots of people on Guam have a great fear of the dentist. I’m not sure this will help!
Humans have had cavities for a very long time. Even Lucy the Australopithecine and her friends and neighbors suffered from toothache. Today we know what causes these painful holes in the teeth: a combination of too much sugar (did you ever notice that the metal-mouth little kids always seem to be holding a soft drink or a candy bar?) and bad cleaning practices. But those causes are very subtle and although we’ve forgotten it, most of your ancestors knew exactly what caused cavities. Tooth worms.
The belief in tooth worms was remarkably widespread. Most people believed that the tooth worm bored a hole into the tooth and hid beneath the surface. It caused a toothache by wriggling around, and the pain subsided when the worm was resting. Although no one could tell you exactly what tooth worms looked like, they’ve taken many forms through the years. British folklore said the tooth worm looked like an eel. The Germans believed the maggot-like worm was red, blue and gray in color. The Chinese and Japanese also believed cavities were caused by tooth worms.
Tooth worms weren’t ruled out as the cause of tooth pain until the 18th century. During the Age of Enlightenment, doctors replaced superstition with science, and the Western world gradually realized what really causes cavities. But the change didn’t happen overnight — some cultures believed tooth worms to be the cause of tooth pain well into the 1900s!
Recently scientists at the University of Maryland Dental School have taken some pictures of the inside of a tooth with an electron microscope and discovered, yep you guessed it, something that looks remarkably like . . . worms. The structures are extremely tiny and they aren’t worms, but what they are is still in question.
The pictures showed cylindrical objects extending or ‘growing’ out of the natural pores or tubules in teeth. There are more than 50,000 of these tubules in every square millimeter of a human tooth. They act as channels that run from the nerve up through the tooth and they transmit hot or cold sensitivity to the nerve.
Dentists are puzzled by the worm-like structures. “Most say ‘I have no idea.’ Others say they are made of bacteria, or minerals, or the branches of yeast cells (C. albicans) which have infected the tooth structure, or perhaps they are a cellular process of the dentinal tubules,” says Gary Hack, DDS, associate professor in the Dental School. For the sake of humoring his students, Hack says, tongue-in-cheek, “I call them tooth worms and I’m sticking to it.”
The scientists at Maryland made some observations that raise new questions. For example, they found two of the ‘worms’ in a single tubule, a discovery that says they probably aren’t natural extensions of the tubules.
The tubules ranged from 2.6 to 3.5 micrometers in diameter (a human hair is about 40 micrometers in diameter) and the worm-like structures were smaller than the tubules they were in. Some of the ‘worms’ extended as far as 9 micrometers out of the tubule opening. Some of them looked hollow but several of them appeared to be solid. Other pictures revealed a comparatively thin, hollow structure emerging from a single tubule.
What are they? Nobody knows yet but I agree with Dr. Hack. I’m going to call them tooth worms!
Scanning electron microscope image of worm-like structures ‘growing’ from dental tubules deep inside a molar. (Credit: University of Maryland, Baltimore)
And speaking of sugar, well, we all know what else it leads to besides cavities; it leads to weight gain. But there’s something else in your diet that leads to even more weight gain and that’s the consumption of animal fat. There’s a new study out that will either make you very angry or make you think “Hmmmm, that doesn’t surprise me at all.”
FAT = . . . . . STUPID?????
New research at Oxford University in England shows that rats fed a high-fat diet have a dramatic reduction in their physical endurance and a decline in their cognitive ability after just nine days. The study was funded by the British Heart Foundation and may have implications not only for those eating lots of high-fat foods, but also athletes looking for the optimal diet for training and patients with metabolic disorders.
Rats that were switched from their standard low-fat feed to a high-fat diet showed a surprisingly quick reduction in their physical performance. After just nine days, they could only run 50 percent as far on a treadmill as those that remained on the low-fat feed.
High-fat diets, common here on Guam, are known to be harmful in the long term and lead to problems like obesity, diabetes and heart failure. They are also associated with a decline in cognitive ability over long time spans. But little attention has been paid to the effect of high-fat diets in the short term.
All 42 rats in the study were initially fed a standard feed with a low fat content of 7.5 percent. Their physical endurance was measured by how long they could run on a treadmill and their short-term or ‘working’ memory was measured in a maze task. Half of the rats were then switched to a high-fat diet where 55 percent of the calories came from fat. After four days of getting used to the new diet, the endurance and cognitive performance of the rats on the low- and high-fat diets was compared for another five days.
The standard feed is low in fat and very few humans (except for perhaps, vegetarians) routinely consume only 7.5 percent of their calories from fat. The high-fat diet, where 55 percent of the calories came from fat, sounds high but it’s actually not extraordinarily high by human standards. A junk food diet would come close to that figure.
But here’s the really interesting part. Not only did the ‘fat rats’ have trouble with the treadmill, they also had trouble with the maze. The number of correct decisions before making a mistake dropped from over six to an average of 5 to 5.5.
While this research was done in rats, the Oxford team is now carrying out similar studies in humans, looking at the effect of a short term high-fat diet on exercise and cognitive ability. The results will be important not only in informing athletes of the best diets to help their training routine, but also in developing ideal diets for patients with metabolic disorders such as diabetes, insulin resistance or obesity. People with such conditions can have high levels of fat in the blood and show poor exercise tolerance, some cognitive decline, and can even develop dementia over time.
Does fat equal stupid? I’ll leave you to draw your own conclusions.
A new study shows that rats, when switched to a high-fat diet from their standard low-fat feed, show a surprisingly quick reduction in their physical performance. (Credit: iStockphoto/Leigh Schindler)
For some of us, that weight gain thing is offset by smoking. Keep reading!
THEY DON’T CALL ‘EM ‘COFFIN NAILS’ FOR NUTHIN’!
It certainly won’t be a best seller, but if people paid as much attention to The Tobacco Atlas as they do to say, Twilight, things here on old planet Earth would be a lot better. Don’t believe me? Don’t stop reading now!
Data found in The Tobacco Atlas, which is published by the American Cancer Society and World Lung Foundation, shows that tobacco use kills some six million people each year- more than a third of them will die from cancer- and drains $500 billion annually from global economies.
According to The Tobacco Atlas, 2.1 million cancer deaths per year will be attributable to tobacco by 2015. By 2030, 83% of these deaths will occur in low and middle-income countries. Unique among all cancer-causing agents, the danger of tobacco is completely preventable if you and your family and neighbors DO NOT SMOKE.
The global economy lost a staggering $500 billion due to tobacco use last year. These economic costs come as a result of lost productivity, misused resources, missed opportunities for taxation, and premature death.
- Because 25 percent of smokers die and many more become ill during their most productive years, income loss devastates families and communities.
- Cigarettes are the world’s most widely smuggled legal consumer product. In 2006, about 600 billion smuggled cigarettes made it to the market, representing an enormous missed tax opportunity for governments, as well as a missed opportunity to prevent many people from starting to smoke and encourage others to quit.
- Tobacco replaces potential food production on almost 4 million hectares of the world’s agricultural land, equal to all of the world’s orange groves or banana plantations.
- In developing countries, smokers spend disproportionate sums of money relative to their incomes that could otherwise be spent on food, healthcare, and other necessities.
Burden Shift to the World’s Poorest Countries
The Tobacco Atlas also showcases a horrible fact. The tobacco industry has shifted its marketing and sales efforts to countries that have less effective public health policies and fewer tobacco controls in place:
- In 2010, 72 percent of those who die from tobacco related illnesses will be in low- and middle-income countries.
- Since 1960 global tobacco production has increased three-fold in low- and middle-resource countries while halving in high-resource countries.
- In Bangladesh alone, if the average household bought food with the money normally spent on tobacco, more than 10 million people would no longer suffer from malnutrition and 350 children under age five could be saved each day.
Look at yourself. Do you smoke? How much do you spend on cigarettes a month? What could you do for your children (besides be around longer) with that money? THINK!! (Unless all those gigantiburgers are keeping you from doing it!)
Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond.
Greetings everyone. Well, I’m back!! My cast came off last week (for those of you who missed it, I broke my arm in October) and I am now typing CAPITAL LETTERS! The DEEP staff was kind enough to allow me this break, which was a big help since I could only type with my left hand. My arm and hand still aren’t quite back to normal, but I’m making great progress.
As you can imagine, several science stories caught my interest during the break and I’ll be sharing them with you in the coming weeks. As I review the files, I have discovered that the largest one (no surprise here!) is the space stories, so off we go on some outer space adventures!
IT CAME FROM THE SKY
We’ll start with a visitor from outer space. One of the largest meteor impacts of the last several hundred years happened over Siberia in 1908. It’s called the Tunguska Event and it flattened 830 square miles of forest and killed several thousand reindeer. If it happened over the east coasts of North America or Asia today, hundreds of millions of people would die.
New research by scientists at Cornell University concludes that the Tunguska explosion was almost certainly caused by a comet impact and they have reached their conclusions by studying the exhaust plume of the space shuttle. The research connects the two events by what followed each about a day later: brilliant, night-visible clouds, or noctilucent clouds.
Noctilucent clouds are the Earth’s highest clouds. They form over the polar regions during the summer months at an altitude of about 50 miles where the temperature is around minus 180 degrees F., They’re made of ice particles and only form at very high altitudes and in extremely cold temperatures.
Following the 1908 Tunguska explosion, the night skies shone brightly for several days across Europe, particularly Great Britain — more than 3,000 miles away. Most researchers think this massive glow was from noctilucent clouds.
They think the massive amount of water vapor spewed into the atmosphere by the comet’s icy nucleus was caught in swirling eddies produced by the explosion and carried thousands of miles away with tremendous energy by a process called two-dimensional turbulence, which explains why the noctilucent clouds formed a day later many thousands of miles away.
The space shuttle exhaust plume, the researchers say, resembled the comet’s action. A single space shuttle flight injects 300 tons of water vapor into the Earth’s thermosphere, and the water particles have been found to travel to the Arctic and Antarctic regions, where they form the clouds after settling into the mesosphere.
The researchers saw the noctilucent cloud phenomenon days after the space shuttle Endeavour (STS-118) launched on Aug. 8, 2007. Similar cloud formations had been observed following launches in 1997 and 2003.
The scientists became intrigued by the historical eyewitness accounts of the aftermath, and concluded that the bright skies must have been the result of noctilucent clouds. The comet would have started to break up at about the same altitude as the release of the exhaust plume from the space shuttle following launch. In both cases, water vapor was injected into the atmosphere.
The scientists have attempted to answer how this water vapor traveled so far without scattering and diffusing, as conventional physics would predict. Their computer models of a similar event shows that the water vapor is caught up in counter-rotating eddies that have extreme energy. Once the water vapor was trapped in these whirling maelstroms, it traveled very quickly – over 200 mph.
So, typhoon-strength winds from a comet impact. Doesn’t surprise me in the least. Will it happen again? Well, there hasn’t been much in the popular press, but there have been somewhere between five and ten reports of massive fireballs in the sky in the last few months. The locations range from Indonesia to Canada to the San Francisco Bay area. I personally wonder just what it is we’re hitting!
In 1927 Professor Leonid Kulik took the first photographs of the massive destruction of the taiga forest after the Tunguska catastrophe. (Credit: Professor Leonid Kulik)
And speaking of things that go past in the night!
TRIPLE YOUR FUN
The Goldstone Tracking Radar system keeps tabs on all sorts of things from the robot satellites we’ve sent out into the solar system to visitors who are just passing through. They took some pictures of a near-Earth asteroid called 1994 CC when it whizzed through our area on 10 June this year.
Now ‘our area’ can be a considerable distance when you’re talking solar system scale and 1994 CC missed us by a million and a half miles.
Before this approach we didn’t know much about 1994 CC. Like most of the asteroids, it’s blacker than charcoal and it’s always night in outer space. But when the astronomers examined the recent radar pictures of 1994 CC they discovered it’s a triple system.
The main body is about 2,300 feet in diameter or about half a mile across. The pictures also show that it has two smaller moonlets that orbit it. The small satellites are roughly 200 feet in diameter. Follow-up observations by the big radar dish at Arecibo also detected all three objects.
The next close Earth flyby for asteroid 1994 CC will be in 2074 when the space rock trio will fly past Earth at a distance of 1.6 million miles. Of the hundreds of near-Earth asteroids observed by radar, only about 1 percent are triple systems.
Radar imaging at NASA’s Goldstone Solar System Radar on June 12 and 14, 2009, revealed that near-Earth asteroid 1994 CC is a triple system. Image Credit: (Credit: NASA/JPL/GSSR)
I mentioned earlier that a large comet or meteor impact would have devastating effects on Earth’s weather, and now we’re off to observe the worst weather you can possibly imagine. Don’t like lightening? Don’t plan on visiting the rings anytime soon!
THE BIGGEST THUNDERBUMPERS
The big planets are noted for big storms. Jupiter has hosted a swirling storm called the Great Red Spot for at least 300 years. No, it’s not a typhoon, it’s a swirling area of high pressure and not low. It is big though; three Earths could be dropped in side by side.
Jupiter also has big lightning storms as well but apparently nothing like those that occur on Saturn. The Cassini spacecraft, which is in orbit around Saturn, has reported that a thunderstorm that erupted on Saturn in January has become the solar system’s longest continuously observed lightning storm.
The monster storm broke out in "Storm Alley," a region 35 degrees south of Saturn’s equator. The storm isn’t
as big as the Great Red Spot but it is nearly 2,000 miles across.
The powerful event was spotted by the US space probe Cassini, using an instrument that can detect radio waves emitted by lightning discharge. Strangely enough, this means that Cassini didn’t see the lightning at first; it heard the static produced by the lightning in its radio detectors.
The Cassini scientists aren’t sure what it is about this particular latitude that produces the bumper crop of storms. There’s a possibility that it’s one of the few places in Saturn’s atmosphere that allows large-scale vertical convection of water clouds, which is necessary for thunderstorms to develop.
But the storms (like ours) may be seasonal. In 1980 and 1981, the Voyager spacecraft flew by Saturn and observed lightning storms near the equator. It could be that the mega-storms will now shift back to equatorial latitudes as Saturn continues its orbit around the Sun. A Saturnian year is 30 Earth years long.
The previous record-breaker for a solar system thunderstorm was an event that lasted seven and a half months, running from November 2007 to July 2008, also spotted by Cassini.
This one has been going on for almost a year now and shows no sign of stopping anytime soon. A year-long thunder storm. My dog would be dead of fright. And we thought we had bad weather sometimes!
And now for a little speculative science.
LIFE AS WE DON’T KNOW IT
One of the things I tell the kids who visit the Planetarium is that there are so many stars out there that no matter what they imagine the aliens to be like, there have probably been aliens like that in the past, will be aliens like that in the future or are aliens like that right now.
The aliens aren’t here however, and will probably never be here because space is so big and so empty that it is virtually impossible to travel to other stars and planets in a human lifetime.
I also tell the kids something very important. Whatever those aliens are like, they are NOT humans dressed up in alien suits. Scientists are beginning to realize that we’ve probably been very parochial in our attitudes toward ‘life’. For all we know, the aliens could be here right now, we just may not recognize them as being alive.
Scientists at a new interdisciplinary research institute in Austria are working to uncover how life might evolve with “exotic” biochemistry and solvents, such as sulfuric acid instead of water.
Traditionally, scientists felt that life could only occur on a planet that circled another star in what we call the ‘habitable zone’; the region around a star in which Earth-like planets with carbon dioxide, water vapor and nitrogen atmospheres could maintain liquid water on their surfaces. We’ve only looked for extraterrestrial life that had metabolisms resembling our own, where water is used as a solvent and the building blocks of life, amino acids, are based on carbon and oxygen. We are slowly beginning to realize that ‘our’ conditions may not be the only conditions under which life could evolve. We can’t rule out that life forms have evolved somewhere that neither rely on water nor on a carbon and oxygen based metabolism.”
One requirement for a life-supporting solvent is that it remains liquid over a large temperature range. Water is liquid between 0°C and 100°C, but other solvents exist which are liquid over more than 200 °C. Such a solvent would allow an ocean on a planet closer to the central star. The reverse scenario is also possible – a liquid ocean of ammonia could exist much further from a star. Furthermore, sulfuric acid is found in the cloud layers of Venus and lakes of methane/ethane cover parts of the surface of the Saturnian satellite, Titan.
The newly established research group at the University of Vienna will investigate the properties of a range of solvents other than water, including their abundance in space, their thermal and biochemical characteristics as well as their ability to support the origin and evolution of life supporting metabolisms.
As I tell my Astronomy students, “Everything you’ve learned in this University is confined to the planet Earth. I’m going to teach you about everything else!” Space IS the final frontier!
Jim is, above all, a passionate eco-humanitarian who has developed his own science talk-radio show to inform The DEEP’s listeners about such newsy topics as global warming, shark-finning and reef protection as well as to explore earth’s many underwater and space mysteries.
sailing 12,000 miles and visiting five countries Jim is back here, ready to explore the depths of the ocean to the deepest frontier, space MORE>>
Lady Pam Eastlick is an expert in both the stars
and seas as a graduate of the University of Guam Marine
Lab and the Director of the UOG Planetarium.