jump to navigation

Autumn starts tomorrow > just look at the sun September 22, 2007

Posted by grhomeboy in Nature, Science.
Tags: , ,
comments closed

Autumn is nearly upon us. According to astronomer Ioannis Fakas, the season officially begins tomorrow at 1.51pm with the autumn equinox.

The Director of the Fakas Institute explained that autumn will last until December 22, after which winter will begin.

According to online encyclopaedia Wikipedia, an equinox is the event when the Sun can be observed to be directly above the Earth’s equator.

This usually takes place around March 20 and September 22 each year. On these dates, night and day are nearly of the same length and the Sun crosses the celestial equator.

In a wider sense, the equinoxes are the two days each year when the centre of the Sun spends an equal amount of time above and below the horizon at every location on Earth. The word equinox derives from the Latin words aequus (equal) and nox (night).

In theory, the day is longer than the night. Commonly the day is defined as the period that sunlight reaches the ground in the absence of local obstacles.

For several reasons the day lasts about 14 minutes longer than the night at the equator, and longer still at sites toward the poles. The real equality of day and night only happens at places far enough from the equator to have at least a seasonal difference in day-length of seven minutes and occurs a few days towards the winter side of each equinox.

Although the word ‘equinox’ implies equal length of day and night, this simply isn’t true. For most locations on earth, there are two distinct identifiable days per year when the length of day and night are closest to being equal.

Those days are commonly referred to as the ‘equiluxes’ to distinguish them from the equinoxes. Equinoxes are points in time, but equiluxes are days. By convention, equiluxes are the days where sunrise and sunset are closest to being exactly 12 hours apart.

This way, you can refer to a single date as being the equilux, when, in reality, it spans sunset on one day to sunset the next, or sunrise on one to sunrise the next.

Symposium this Sunday in Athens September 20, 2007

Posted by grhomeboy in Environment, Science, Shows & Conferences.
comments closed

This coming Sunday the interest of the international scientific community will be focused on Athens.

The Athens Academy, the National Observatory, the International Ozone Commission, the World Meteorological Organization and the UN Environment Program are organizing a scientific symposium on Ozone Depletion, September 23-26.

Over 200 distinguished scientists and academics are expected to take part, among them Nobel Prize-winners Professor Paul Crutzen, Mario Molina and F. Sherwood Rowland. The results of the implementation of the Montreal Protocol will be discussed as well as the interplay between the changes in the ozone and climatic change.

The symposium will be held in the Athens Concert Hall and will take place under the aegis of Greek President Karolos Papoulias.

Nanoscience and Nanotechnology September 14, 2007

Posted by grhomeboy in Science, Shows & Conferences, Technology.
comments closed

Speakers at the 4th International Conference on Nanoscience and Nanotechnologies that recently took place in Thessaloniki, northern Greece, stressed that nanoscience applications were on the verge of revolutionising medicine and biotechnology.

They predicted that artificial organs made of nanomaterials that could be used in transplants would make their appearance in the next three years, as well as new cancer therapies using gold nanoparticles. Other possible applications included the healing of heart tissue after cardiac arrest, when about 30 percent of a heart’s tissue is destroyed.

The conference was organised by Physics and Thin Membranes-Nanosystems and Nanometry Laboratory at Thessaloniki’s Aristotelian University. According to Professor Thomas Tsakalakos of Rutgers University, nanotechnology aims to create materials that did not exist and extremely small vehicles that could carry targeted medication where it was needed to cure disease. He also said that research in Greece requires more investment, a more inter-disciplinary approach and more “unusual” or innovative thinking by scientists.

The EU plans to give member-states 3.5 billion euros for research in nanotechnology, and the turnover from the trade in nanotools, nano-materials, nano-systems and nanobiotechnology is expected to be somewhere in the range of 3.0 trillion euros by 2015. Speakers said Greece has able scientists but that the relationship between industry and research was weak.

Take time to enjoy stargazing August 5, 2007

Posted by grhomeboy in Science.
comments closed

It’s time for that great summer ritual > lying out on a rock all night watching the stars.

An added incentive to go stargazing is the annual Perseid meteor shower this week, expected to peak overnight Sunday, August 12 to Monday, August 13.

Washed out by a full moon last year, the rain of falling stars will unfold this summer in the dark of the moon, ideal conditions. Whether you get out camping or simply find a dark corner in the neighbourhood, lie back on a blanket or lawn chair and enjoy!

The meteors, burning bits of comet dust, can appear anywhere in the sky, but seem to radiate from the constellation Perseus, rising in the northeast below the “big W” constellation, Casseopeia. Like people of all cultures, the ancient Greeks linked legends of gods, heroes and human foibles with the stars. Six constellations in that part of the sky involve the winged hero Perseus saving Andromeda, a beautiful maiden chained to a rock, from being devoured by a sea monster.

Science in Ancient Greece July 22, 2007

Posted by grhomeboy in Science.
comments closed

The theme of this 84th edition of TB is science in Ancient Greece, so we’ll be exploring what that meant to them, and jumping ahead a couple millenia to find out what it means to us.

It’s hard to say whether or not the Ancient Greeks ever really practiced science. They claimed to be proponents of reason and observation, but their observations were usually brief and they leaned on reason and rhetoric to explain the world around them. They more often found truth in logic and faith. Surely, the meaning of all of these words – science, reason, truth, faith, have changed over the millenia and the Ancient Greeks were indeed explorers and discoverers. Regardless, they have done much for laying the groundwork for modern science.

Aristotle is most often hailed as a great zoologist, credited with writing extensive treatises on the subject. This has become more contentious of late. Aristotle did in fact write some early information on marine animals, but his later works could be attributed to Theophrastrus, his successor at Lyceum. Regardless, Aristotle had a hand in their formation. Within the treatises, over 1,000 plants and animals are categorized and described according to their physical and behavioral characteristics (though not on a species by species basis).

Ancient Greek astronomy has its roots in myth and ritual. Like many other ancient cultures, the Greeks saw their deities in the stars, and assigned them names as constellations. But starting in around 500 BCE, with Thales’ accurate measurements of the sun’s diameter, Pythagoras’ observation that the world is round and Anaxagoras’ notions that the sun and moon were in fact natural phenomena (leading to his arrest for contradicting the state religion), astronomy was beginning to take shape in the descriptions of celestial bodies.

Read this article at > ScienceBlogs

Greek scientists roll up for better hydrogen fuel storage June 25, 2007

Posted by grhomeboy in Energy, Science.
comments closed

The thorny problem of how to store hydrogen fuel safely for future vehicles and portable gadgets could be solved by simply storing it in nanoscopic scrolls of carbon.

Scientists in Greece say they have found a way to make so-called “carbon nanoscrolls” store more hydrogen than any other material.

By adding impurities to rolled sheets of carbon in detailed computer simulations, they found they could control how tightly the scrolls wind up and, hence, how much hydrogen they adsorb. This result is very promising because it provides a potential solution to one of the major problems of hydrogen storage for mobile applications, says George Froudakis at the University of Crete, who led the work.

Hydrogen has been much touted as the clean fuel of the future for electric vehicles and portable devices. But, despite holding more energy than hydrocarbon fuels, its incredibly low density makes it difficult to store in sufficient quantity to make it worthwhile.

Liquefying hydrogen by placing it under great pressure is both expensive and potentially dangerous. Even then, with a density of just one tenth that of water, it would be necessary to store four times the volume of liquid to match the energy content of gasoline.

“Most of the scientists working on this field of research believe that the solution to this problem will arise from the synthesis of new materials,” Froudakis says.

Indeed, in 2003 the US Department of Energy (DOE) set a target of developing novel materials capable of reversibly storing enough hydrogen to make up 6% of their total weight by 2010. The idea is to find materials with high surface areas that soak up hydrogen at much higher densities than previously possible, and without the need for extreme cooling or pressurisation.

To address this problem, Froudakis and colleagues carried out computer simulations to see how the hydrogen uptake of carbon nanoscrolls could be affected by adding quantities of different alkali metals. These impurities cause the atomic distance between the layers of a scroll to vary. Their findings suggest that adding lithium ions should increase the uptake of hydrogen at atmospheric pressure and room temperature from 0.19% to 3.31%.

This is twice the amount that other materials have achieved. Furthermore, hydrogen uptake should increase as the temperature is reduced, the researchers say. These are significant quantities of hydrogen, says Frantisek Svec, a researcher at Lawrence Berkeley National Laboratory, in California, US. but they still fall short of the DOE targets. Also, as the study is only a simulation, the results will need to be confirmed experimentally. “Unfortunately, in practice, these carbon-based materials are most often much less encouraging,” Svec says.

The Story of the Archimedes Manuscript June 23, 2007

Posted by grhomeboy in Archaeology Greece, Science, Technology.
comments closed

For 2,000 years, the document written by one of antiquity’s greatest mathematicians was ill treated, torn apart and allowed to decay. Now, US historians have decoded the Archimedes book. But is it really new?

When the Romans advanced to Sicily in the Second Punic War and finally captured the proud city of Syracuse, one of their soldiers met an old man who, surrounded by the din of battle, was calmly drawing geometric figures in the sand. “Do not disturb my circles,” the eccentric old man called out. The legionnaire killed him with his sword.

That, at least, is the legend. The truth is a different story altogether. Placed in charge of King Hieron II’s artillery equipment, Archimedes later played an important military role during the siege of Syracuse. He invented powerful catapults to defend his homeland, using cranes to hurl heavy boulders from the walls of the fortress at enemy ships. Mirrors were also used, it is said, to direct burning rays of sunlight at the Roman armada, setting the ships on fire. The Sicilians resisted the onslaught of the ambitious Roman republic for more than two years.

In short, had the legionnaire really speared the eccentric old man with his sword, he would have done the Romans a great service. In addition to being an oddball scholar, Archimedes was a skilled inventor of weapons.

How Many Grains of Sand > He was so skilled, in fact, that it almost seemed that he could stop Rome’s large army single-handedly. But in the end Archimedes fell victim to brute force after all. One of the greatest inventors of all time, Archimedes was killed at the age of 73. His murder, notes British philosopher Paul Strathern, was “the Romans’ only decisive contribution to mathematics.”

Archimedes prepared the way for integral calculus and approximated the number Pi. He discovered the law of leverage and invented new formulas to calculate the properties of cylinders and spheres. He once yelled “Eureka” while bathing, after having dreamed up the concept of specific weight while splashing around. He even specified the number of grains of sand that could fit into the universe: 1063. Until then the Greeks had merely left it at a “myriad” (or 10,000).

“It took almost 2,000 years before anyone else could hold a candle to him,” Strathern says about this extraordinary man, who lived from 285 to 212 B.C. But brilliance had its drawbacks. Archimedes was often so engrossed in thought that he would forget to eat — and he bathed infrequently. But aside from that, researchers know little about this oddball from the early days of geometry and mechanics. Unfortunately many of his writings were lost, while the rest have been handed down in the form of Arabic and Latin copies. Vandals destroyed his famous planetarium, with its water-powered wheelworks.

But now a Greek original has been discovered after all. In “The Archimedes Codex,” recently published in English, two US researchers describe the decoding of a manuscript from the early days of mathematics. It took the authors years of painstaking work to “extract the secrets from these faded letters.”

Old Manuscript for $2.2 Million > The Beck publishing house, which will first publish the German edition on Sept. 17, is also heavily promoting the book. With a scheduled initial printing of 20,000 copies, Beck is advertising the book as an “important work.” “Our scientific view of the world is turned upside down,” the publisher raves in the press release.

The fuss revolves around a manuscript that caused an uproar once before, in October 1998, when a fragile, handwritten manuscript with mold spots and blackened edges was offered for sale in an auction at Christie’s in New York. After a contentious bidding war, the auctioneer’s hammer fell at a price of $2.2 million.

An anonymous “billionaire from the computer industry” had apparently purchased the rare work. But who was it? Neither the auction house nor the new owner was willing to answer that question. Insiders are now certain that it was Jeffrey Bezos, the founder and CEO of online book retailer Amazon.

The cloak-and-dagger operation makes sense, given the dark suspicions attached to the Archimedes manuscript. Legal papers suggest that the wood-bound math tome was stolen in the Middle East. The Greek Orthodox patriarch of Jerusalem has gone to court twice, both times unsuccessfully, in an effort to gain control over the document. But the conflict continues to simmer.

At least the wealthy US buyer was accommodating enough to lend the manuscript to the Walters Art Museum in Baltimore. As a museum employee recalls, “Mr. B.” carried the booklover’s gem in a “blue bag” up the marble staircase and into the columned foyer of the building, which is built in the style of a Genovese Renaissance palace.

The loan has triggered a flurry of excitement at the Walters, which also features Egyptian funeral papyrus and Napoleon’s diaries in its collection. Greek scholars, physicists and digital photographers are attempting to decode the tattered work. According to curator William Noel, the work is “not much bigger than a box of sugar cubes” and consists of 174 “rigid and warped” pages. “The book,” says Noel, “was on the verge of disintegrating.”

Bombarded with X-Rays > Read the rest of this article and view related photos at > Spiegel

Article by Matthias Schulz. Copyright by Spiegel Online.