Friday, May 9, 2008
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> Labeled before and after images The first cyclone of the 2008 season in the northern Indian Ocean was a devastating one for Burma. According to reports from Accuweather.com, Cyclone Nargis made landfall with sustained winds of 130 mph and gusts of 150-160 mph, which is the equivalent of a strong Category 3 or minimal Category 4 hurricane. News reports stated that several thousand people have been killed, and thousands more were missing as of May 5.
Flood water can be difficult to see in photo-like satellite images, particularly when the water is muddy. This pair of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite use a combination of visible and infrared light to make floodwaters obvious. Water is blue or nearly black, vegetation is bright green, bare ground is tan, and clouds are white or light blue.
On April 15, rivers and lakes are sharply defined against a backdrop of vegetation and fallow agricultural land. The Irrawaddy River flows south through the left-hand side of the image, splitting into numerous distributaries known as the Mouths of the Irrawaddy. The wetlands near the shore are a deep blue green. Cyclone Nargis came ashore across the Mouths of the Irrawaddy and followed the coastline northeast.
NASA's Terra satellite captured this image of the Myanmar coast on May 5, 2008, showing the devastation of flooding caused by Tropical Cyclone Nargis. Credit: NASA/MODIS Rapid Response Team
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> Labeled before and after images
The entire coastal plain is flooded in the May 5 image. The fallow agricultural areas appear to have been especially hard hit. For example, Yangôn (population over 4 million) is almost completely surrounded by floods. Several large cities (population 100,000–500,000) are in the affected area. Muddy runoff colors the Gulf of Martaban turquoise.
The high-resolution image provided above is at MODIS’ maximum spatial resolution (level of detail) of 250 meters per pixel. The MODIS Rapid Response Team provides twice-daily images of the region in additional resolutions and formats, including photo-like natural color.
Granted, it might not seem like such a big deal when astronomers find some of the missing mass in the universe, since there's very little that isn't missing. Roughly 95 percent of the cosmos is either dark matter or dark energy. About five percent of the universe is made up of the normal mass we're familiar with—baryonic matter. Yet by adding up the known stars and galaxies and gas, astronomers have only accounted for about half of that five percent.
Now, scientists using the XMM-Newton, ESA's super-sensitive detector, have begun to pick up some of that missing mass by studying X-ray emissions coming from tendrils of gas stretching between two galaxy clusters, Abell 222 and Abell 223. These gaseous filaments connect many other galaxies in the universe, forming a kind of cosmic web, and studying those other links will be the next task. "This is only the beginning. To understand the distribution of the matter within the cosmic web, we have to see more systems like this one," says astronomer Norbert Werner. "And ultimately launch a dedicated space observatory to observe the cosmic web with a much higher sensitivity than possible with current missions."
It was once considered the most dangerous object in the universe, heading for Earth with the explosive power of 84 Hiroshimas. Now an asteroid called 2000SG344, a lump of rock barely the size of a large yacht, is in the spotlight again, this time as a contender for the next giant leap for mankind.
Nasa engineers have identified the 1.1m tonne asteroid, which in 2000 was given a significant chance of slamming into Earth, as a potential landing site for astronauts, ahead of the Bush administration's plans to venture deeper into the solar system with a crewed voyage to Mars.
The mission - the first to what officials call a Near Earth Object (NEO) - is being floated within the US space agency as a crucial stepping stone to future space exploration.
A report seen by the Guardian notes that by sending astronauts on a three-month journey to the hurtling asteroid, scientists believe they would learn more about the psychological effects of long-term missions and the risks of working in deep space, and it would allow astronauts to test kits to convert subsurface ice into drinking water, breathable oxygen and even hydrogen to top up rocket fuel. All of which would be invaluable before embarking on a two-year expedition to Mars.
Under the Bush administration, Nasa has been charged with sending astronauts back to the moon, beginning in 2020 and culminating in a permanent lunar outpost, itself a jumping off point for more distant Mars missions. With the agency's ageing fleet of space shuttles due to be retired soon after 2010, the agency has begun work on a replacement called Orion and a series of Ares rockets that will blast them into orbit.
In a study due to be published next month, engineers at Nasa's Johnson Space Centre in Houston and Ames Research Centre in California flesh out plans to use Orion for a three to six month round-trip to the asteroid, with astronauts spending a week or two on the rock's surface.
As well as giving space officials a taste of more complex missions, samples taken from the rock could help scientists understand more about the birth of the solar system and how best to defend against asteroids that veer into Earth's path.
"An asteroid will one day be on a collision course with Earth. Doesn't it make sense, after going to the moon, to start learning more about them? Our study shows it makes perfect sense to do this soon after going back to the moon," said Rob Landis, an engineer at Johnson Space Centre and co-author of the report, which is due to be published in the journal Acta Astronautica.
More precise measurements of the orbit of 2000SG344 have allayed fears that it could hit Earth sometime around the end of September 2030, but the asteroid is still expected to come close in astronomical terms.
The report lays out plans for a crew of two to rendezvous with a speeding asteroid that is due to pass close by Earth. After a seven-week outward journey, the Orion capsule would swing around and close in on the rock.
Because gravity is close to zero on asteroids, the capsule would need to attach itself, possibly by firing anchors into the surface. For the same reason, astronauts would not be able to walk around on the surface as they did on the moon. "On some of these asteroids, you could jump up and go into orbit, or maybe even leave for good," said Landis.
A round trip to an asteroid could be done with less fuel than a moon mission, but is technically very challenging. The asteroid is only 40 metres across and spins as it hurtles through space at 28,000mph.
Landis thinks that a trip to an asteroid could capture imaginations even more than a return to our nearest celestial neighbour. "When we head back to the moon, I think we'll see many of the same scenes we saw in the 60s and 70s Apollo programme. We've been to the moon, we got that T-shirt back in 1969. But whenever we've sent robotic probes to look at asteroids, we've always been surprised at what we've seen," he said.
Because asteroids were forged in the earliest days of the solar system, analysing samples from them could shed light on the conditions that prevailed when the Earth was formed.
"Near Earth objects are a potential collision hazard to Earth and it may one day be necessary to deflect an asteroid from a collision course with Earth," said Ian Crawford, a planetary scientist at Birkbeck College, London. "Having the capability in your back pocket to deflect an asteroid might be a good insurance policy for the future, and for that, you want to know what they are made of, how to rendezvous with them, and whether you risk getting hit by debris if you fire something at it."
Mankind has always been driven by contradictory drives. The relentless curiosity that pushes us forward and is directly responsible for our progress from caves to cities. The fear of change that tells us "hang on, these caves/cities are really nice, we don't want to risk losing them." There isn't any greater potential threat to the status quo than the discovery of extraterrestrial life, which is why some people would prefer we didn't try.
There has been some outrage recently over attempts to contact intelligent aliens, where instead of hiding in the corner and listening real hard some astronomers beamed intense directional messages up up and away. Critics decried these actions as dangerous, though their fears reveal more about us than any eventual ETs. They assume that they would be similar to humanity, so their first response to finding a more primitive culture would be to exploit the hell out of it. While such a fate might be pleasingly ironic (for anyone who isn't human, at least), others contend that any species that can make the journey here has advanced to a point where their goals are rather higher-minded than "Shoot us".
Dr Alexander Zaitzev, of the Institute of Radio Engineering and Electronics at the Russian Academy of Sciences, doesn't think much of these worries either way. A proponent of METI (Messaging to Extra-Terrestrial Intelligence), in a recent paper he shows that the odds of one of the METI messages being detected is a millionth of that due to powerful radar pulses regularly used in astronomical investigation. Though whether writing a paper saying "This METI thing we're doing has only a tiny chance of working" is overall a good idea remains to be seen. An important point is that METI represents an intentional will to make contact, rather than the accidental alien interception of some random radiation from Earth - the difference between saying "Hello!" and just being a suspicious strange noise late at night.
Most of the objections to contacting aliens are weak under close examination. We can't suddenly decide to hide after fifty years of pumping electromagnetic radiation into space without rhyme or reason - in fact, we'd better hope that an advanced civilization doesn't catch an episode of "American Idol" and just vaporize us outright. Suddenly keeping quiet would be like a drunk boyfriend carefully taking off his shoes after knocking over a bookshelf on his way to the bedroom.
Then there's the assumption that aliens would have the same kind of technology we do - despite the extremely obvious fact that our technology can't actually get to other planets. Any attempt to mask radio emissions will likely look like cavemen closing their eyes to hide from satellite imaging.
The simple fact is that certain people have always opposed progress while other, better people have driven it. "Experts" decried boiled water as unhealthy compared the vital stuff straight from the river, cursed antibiotics as a temporary placebo, and confidently declared that computers were nothing but expensive toys. As an intelligent species we must make every effort to contact anyone or thing we can - and if you don't like it, there are some lovely caves you can move back to.
At least one of Britain's birds appears to be coping well as climate change alters the availability of a key food.
Researchers found that great tits are laying eggs earlier in the spring than they used to, keeping step with the earlier emergence of caterpillars.
Writing in the journal Science, they point out that the same birds in the Netherlands have not managed to adjust. Understanding why some species in some places are affected more than others by climatic shifts is vital, they say.
The Royal Society for the Protection of Birds (RSPB) commented that other species are likely to fare much worse than great tits as temperatures rise.
The research uses a long record of great tits in a breeding site at Wytham Woods near Oxford, where observations began in 1947.
The finding is surprising in that the birds are using the same old rules, but the rules still work
Professor Marcel Visser
"We think it’s the longest running population study of wild animals anywhere in the world where animals are marked (ringed)," said Ben Sheldon of Oxford University, who led the new research.
"The population contains about 400 breeding pairs, and they produce between them 2,000 or more offspring each year - so over the course of the study about 80,000 birds have been ringed and studied," he told BBC News.
The current work used records going back only to 1961, when a standard methodology was adopted.
The great tits are laying eggs now about two weeks earlier in the year than they were 47 years ago.
The timing is crucial, because for the two-week period after they hatch, the chicks have to gobble down huge quantities of winter moth caterpillars which only emerge for a short period.
"Winter moth larvae can make up up to 90% of the biomass of insects on oak trees at that time," said Professor Sheldon.
"Great tits have eight or nine babies in a brood, and each of them will eat about 70 caterpillars a day.
The chicks hatch and are fully grown within two weeks, so they need something that's really abundant - that's why they synchonise their breeding so hatching co-incides with the emergence of the caterpillars."
The caterpillars' appearance is triggered by ambient temperature - that has been shown in the laboratory - and it is believed that great tits also begin their breeding cycle in response to temperatures.
Their movement to an earlier breeding time does not involve an evolutionary change, the scientists believe - it is simply that individual birds are able to change their behaviour, in the same way that they have presumably adapted to warmer or cooler phases before the era of human-induced global warming.
In Wytham, the behaviour of the two species is changing in step; but other situations are very different.
Three years ago, Marcel Visser from the Netherlands Institute of Ecology in Heteren collated a number of these cases.
The North American wood warbler has not adapted its migration pattern to the earlier emergence of caterpillars in its breeding ground, and the Dutch honey buzzard is also failing to adapt to the earlier appearance of wasps, which it eats.
The red admiral butterfly is arriving on the UK's shores earlier from its winter grounds in north Africa; but the staple food of its larvae, the common nettle, continues to flower at the same time each year.
Wytham Woods are home to about 400 breeding pairs of great tits
Just across the North Sea in Holland, Professor Visser has also found that great tits are faring very differently from their British cousins; the breeding time is advancing each year, but the emergence of caterpillars is advancing three times faster.
"The UK finding is to some extent surprising in that the birds are using the same old rules, but the rules still work," he told BBC News.
"In our study population, the same old rules don't work any more; so it's an interesting question as to which situation is the normal one and which is the exception."
The RSPB and other conservation bodies have regularly warned that climate shifts could have a devastating impact on some species; and they believe the new research does not change that picture.
"It's great to hear that the great tit is able to keep pace with the rapid rate of climate change, but then it's probably in the best place to do that," observed RSPB spokesman Grahame Madge.
"They're abundant birds, they can live in gardens, woodland and open country, and they churn out large numbers of young in a short space of time, so they're better able to learn changes in behaviour."
The organisation believes - as do others - that climate change is one of the main cuplrits for the abrupt declines in some seabird populations around UK coasts in recent years.
The Oxford and Heteren groups are now planning to collaborate on a study to elucidate why some populations apparently adapt well to climate change, and others do not.
"Our study shows that sometimes individuals can be very flexible in their behaviour," said Ben Sheldon.
"What we want to do is to try and understand why some species are flexible and others aren't - it's the ones that aren't flexible that are going to be at risk."
Intelligence, it turns out, is a high-priced option. It takes more upkeep, burns more fuel and is slow off the starting line because it depends on learning — a gradual process — instead of instinct. Plenty of other species are able to learn, and one of the things they’ve apparently learned is when to stop.
Is there an adaptive value to limited intelligence? That’s the question behind this new research. I like it. Instead of casting a wistful glance backward at all the species we’ve left in the dust I.Q.-wise, it implicitly asks what the real costs of our own intelligence might be. This is on the mind of every animal I’ve ever met.
Every chicken that looks at you sideways — which is how they all look at you — is really saying what Thoreau said less succinctly: you are endeavoring to solve the problem of a livelihood by a formula more complicated than the problem itself. Thoreau himself would not dispute that he was hoping to recover the chicken’s point of view. He went to Walden Pond “to remember well his ignorance.”Research on animal intelligence also makes me wonder what experiments animals would perform on humans if they had the chance. Every cat with an owner, for instance, is running a small-scale study in operant conditioning. I believe that if animals ran the labs, they would test us to determine the limits of our patience, our faithfulness, our memory for terrain. They would try to decide what intelligence in humans is really for, not merely how much of it there is. Above all, they would hope to study a fundamental question: Are humans actually aware of the world they live in? So far the results are inconclusive.