| On the Hunt for Mammoth DNA [Sciam Observations Blog] SciAm frequent contributor Charles Q. [More] feeds.feedburner.com |
Judging a Book by Its Genomes [The following is an exact transcript of this podcast.]Thousands of medieval European books survive to this day. Authors and scribes carefully handwrote the works on parchments made of animal skins. But the writers didn’t always bother to sign and date their works. So we had no way of knowing where and when most of the documents are from. Until now. [More] pheedo.com |
On the Web - Feb 2009 Science TalkThe Science of Pain [More] pheedo.com |
Vesuvius erupts After centuries of dormancy, Mount Vesuvius erupts in southern Italy, devastating the prosperous Roman cities of Pompeii and Herculaneum and killing thousands. The cities, buried under a thick layer of volcanic material and mud, were never rebuilt and largely forgotten in the course of history. In the 18th century, Pompeii and Herculaneum were rediscovered and excavated, providing an unprecedented archaeological record of the everyday life of an ancient civilization, startlingly preserved in sudden death.The ancient cities of Pompeii and Herculaneum thrived near the base of Mount Vesuvius at the Bay of Naples. In the time of the early Roman Empire, 20,000 people lived in Pompeii, including merchants, manufacturers, and farmers who exploited the rich soil of the region with numerous vineyards and orchards. None suspected that the black fertile earth was the legacy of earlier eruptions of Mount Vesuvius. Herculaneum was a city of 5,000 and a favorite summer destination for rich Romans. Named for the mythic hero Hercules, Herculaneum housed opulent villas and grand Roman baths. Gambling artifacts found in Herculaneum and a brothel unearthed in Pompeii attest to the decadent nature of the cities. There were smaller resort communities in the area as well, such as the quiet little town of Stabiae.At noon on August 24, 79 A.D., this pleasure and prosperity came to an end when the peak of Mount Vesuvius exploded, propelling a 10-mile mushroom cloud of ash and pumice into the stratosphere. For the next 12 hours, volcanic ash and a hail of pumice stones up to 3 inches in diameter showered Pompeii, forcing the city's occupants to flee in terror. Some 2,000 people stayed in Pompeii, holed up in cellars or stone structures, hoping to wait out the eruption.A westerly wind protected Herculaneum from the initial stage of the eruption, but then a giant cloud of hot ash and gas surged down the western flank of Vesuvius, engulfing the city and burning or asphyxiating all who remained. This lethal cloud was followed by a flood of volcanic mud and rock, burying the city.The people who remained in Pompeii were killed on the morning of August 25 when a cloud of toxic gas poured into the city, suffocating all that remained. A flow of rock and ash followed, collapsing roofs and walls and burying the dead.Much of what we know about the eruption comes from an account by Pliny the Younger, who was staying west along the Bay of Naples when Vesuvius exploded. In two letters to the historian Tacitus, he told of how "people covered their heads with pillows, the only defense against a shower of stones," and of how "a dark and horrible cloud charged with combustible matter suddenly broke and set forth. Some bewailed their own fate. Others prayed to die." Pliny, only 17 at the time, escaped the catastrophe and later became a noted Roman writer and administrator. His uncle, Pliny the Elder, was less lucky. Pliny the Elder, a celebrated naturalist, at the time of the eruption was the commander of the Roman fleet in the Bay of Naples. After Vesuvius exploded, he took his boats across the bay to Stabiae, to investigate the eruption and reassure terrified citizens. After going ashore, he was overcome by toxic gas and died.According to Pliny the Younger's account, the eruption lasted 18 hours. Pompeii was buried under 14 to 17 feet of ash and pumice, and the nearby seacoast was drastically changed. Herculaneum was buried under more than 60 feet of mud and volcanic material. Some residents of Pompeii later returned to dig out their destroyed homes and salvage their valuables, but many treasures were left and then forgotten.In the 18th century, a well digger unearthed a marble statue on the site of Herculaneum. The local government excavated some other valuable art objects, but the project was abandoned. In 1748, a farmer found traces of Pompeii beneath his vineyard. Since then, excavations have gone on nearly without interruption until the present. In 1927, the Italian government resumed the excavation of Herculaneum, retrieving numerous art treasures, including bronze and marble statues and paintings.The remains of 2,000 men, women, and children were found at Pompeii. After perishing from asphyxiation, their bodies were covered with ash that hardened and preserved the outline of their bodies. Later, their bodies decomposed to skeletal remains, leaving a kind of plaster mold behind. Archaeologists who found these molds filled the hollows with plaster, revealing in grim detail the death pose of the victims of Vesuvius. The rest of the city is likewise frozen in time, and ordinary objects that tell the story of everyday life in Pompeii are as valuable to archaeologists as the great unearthed statues and frescoes. It was not until 1982 that the first human remains were found at Herculaneum, and these hundreds of skeletons bear ghastly burn marks that testifies to horrifying deaths.Today, Mount Vesuvius is the only active volcano on the European mainland. Its last eruption was in 1944 and its last major eruption was in 1631. Another eruption is expected in the near future, would could be devastating for the 700,000 people who live in the "death zones" around Vesuvius. history.com |
Krakatau explodes The most powerful volcanic eruption in recorded history occurs on Krakatau (also called Krakatoa), a small, uninhabited volcanic island located west of Sumatra in Indonesia, on this day in 1883. Heard 3,000 miles away, the explosions threw five cubic miles of earth 50 miles into the air, created 120-foot tsunamis and killed 36,000 people.Krakatau exhibited its first stirrings in more than 200 years on May 20, 1883. A German warship passing by reported a seven-mile high cloud of ash and dust over Krakatau. For the next two months, similar explosions would be witnessed by commercial liners and natives on nearby Java and Sumatra. With little to no idea of the impending catastrophe, the local inhabitants greeted the volcanic activity with festive excitement.On August 26 and August 27, excitement turned to horror as Krakatau literally blew itself apart, setting off a chain of natural disasters that would be felt around the world for years to come. An enormous blast on the afternoon of August 26 destroyed the northern two-thirds of the island; as it plunged into the Sunda Strait, between the Java Sea and Indian Ocean, the gushing mountain generated a series of pyroclastic flows (fast-moving fluid bodies of molten gas, ash and rock) and monstrous tsunamis that swept over nearby coastlines. Four more eruptions beginning at 5:30 a.m. the following day proved cataclysmic. The explosions could be heard as far as 3,000 miles away, and ash was propelled to a height of 50 miles. Fine dust from the explosion drifted around the earth, causing spectacular sunsets and forming an atmospheric veil that lowered temperatures worldwide by several degrees.Of the estimated 36,000 deaths resulting from the eruption, at least 31,000 were caused by the tsunamis created when much of the island fell into the water. The greatest of these waves measured 120 feet high, and washed over nearby islands, stripping away vegetation and carrying people out to sea. Another 4,500 people were scorched to death from the pyroclastic flows that rolled over the sea, stretching as far as 40 miles, according to some sources.In addition to Krakatau, which is still active, Indonesia has another 130 active volcanoes, the most of any country in the world. history.com |