The first ever evidence of a comet entering Earth's atmosphere and exploding, raining down a shock wave of fire which obliterated every life form in its path, has been discovered by a team of South African scientists and international collaborators, and will be presented at a public lecture on Thursday.

The discovery has not only provided the first definitive proof of a comet striking Earth, millions of years ago, but it could also help us to unlock, in the future, the secrets of the formation of our solar system.

"Comets always visit our skies - they're these dirty snowballs of ice mixed with dust - but never before in history has material from a comet ever been found on Earth," says Professor David Block of Wits University.

The comet entered Earth's atmosphere above Egypt about 28 million years ago. As it entered the atmosphere, it exploded, heating up the sand beneath it to a temperature of about 2 000 degrees Celsius, and resulting in the formation of a huge amount of yellow silica glass which lies scattered over a 6 000 square kilometer area in the Sahara. A magnificent specimen of the glass, polished by ancient jewellers, is found in Tutankhamun's brooch with its striking yellow-brown scarab.

Gold and silver pieces as well as bones and pottery from 1500 years ago have been discovered in Lake Titicaca by underwater archaeologists, a researcher says.

"We found 2000 objects and fragments," Christophe Delaere, the Belgian co-director of the Huinaimarca Project that unearthed the items, said at a ceremony in La Paz.

President Evo Morales, Bolivia's minister of culture and diplomats from Belgium were also in attendance. The expedition began two months ago on the Bolivian side of the lake, which is shared with Peru. Underwater explorations turned up objects from different eras, both Inca era and pre-Inca (1438-1533).

The project unearthed 31 gold fragments, mainly around the Isla del Sol, where legend holds that mythical founders of the Incan empire emerged from the lake's waters. Underwater excavations were carried out in other parts of the lake where objects from different dates were found.

"There are ceramics and urns from more than 500 to 800 years ago," Delaere said.

Elsewhere, 1500-year-old objects such as stone vessels, incense containers and figures of animals such as pumas were found. Tales about the lake containing underwater citadels and wealth supposedly stashed by indigenous Quechua and Aymara people from Spanish conquistadores have existed for centuries in Bolivia.

In the late 1960s, French explorer Jacques-Yves Cousteau conducted several expeditions in Lake Titicaca, finding signs of a civilisation. Morales stressed that Bolivia, South America's poorest nation, is keen to recover its national patrimony on display in countries in Europe and the US.

Source: Agence France-Presse

One of history's great disaster mysteries may be solved - the case of the largest volcanic eruption in the last 3,700 years. Nearly 800 years ago, the blast that was recorded, and then forgotten, may also have created a "Pompeii of the Far East," researchers suggest, which might lie buried and waiting for discovery on an Indonesian island.

The source of an eruption that scattered ash from pole to pole has been pinpointed as Samalas volcano on Indonesia's Lombok Island. The research team, led by geographer Franck Lavigne of the Université Paris 1 Panthéon-Sorbonne, has now dated the event to between May and October of 1257. The findings were published today in the Proceedings of the National Academy of Sciences.

"It's been a long time that some people have been looking," said Lavigne. After glaciologists turned up evidence for the blast three decades ago, volcano experts had looked for the origin of the eruption everywhere from New Zealand's Okataina volcano to Mexico's El Chichón.

The previously unattributed eruption was an estimated eight times as large as the famed Krakatau explosion (1883) and twice as large as Tambora in 1815, the researchers estimate. (Related: "Tambora: The Greatest Explosion in History.") "Until now we thought that Tambora was the largest eruption for 3,700 years," Lavigne said, but the study reveals that the 1257 event was even larger.

A carved stone found marking a Bronze Age grave in the Ukraine is the oldest sundial of its kind ever found, a new study reveals.

The sundial may have marked the final resting place of a young man sacrificed or otherwise marked as a messenger to the gods or ancestors, said study researcher Larisa Vodolazhskaya of the Archaeoastronomical Research Center at Southern Federal University in Russia. Vodolazhskaya analyzed the geometry of the tire-size stone and its carvings, confirming the stone would have marked the time using a system of parallel lines and an elliptical pattern of circular depressions.

The elliptical pattern makes the carving an analemmatic sundial. A traditional sundial marks the time using a gnomon, a fixed vertical that casts a shadow. An analemmatic sundial has a gnomon that must move every day of the year to adjust to the changing position of the sun in the sky. [See Images of the Ancient Sundial]

Shaken, scorched and boiled in its own juices, this 4000-year-old human brain has been through a lot.

It may look like nothing more than a bit of burnt log, but it is one of the oldest brains ever found. Its discovery, and the story now being pieced together of its owner's last hours, offers the tantalising prospect that archaeological remains could harbour more ancient brain specimens than thought. If that's the case, it potentially opens the way to studying the health of the brain in prehistoric times.

Brain tissue is rich in enzymes that cause cells to break down rapidly after death, but this process can be halted if conditions are right. For instance, brain tissue has been found in the perfectly preserved body of an Inca child sacrificed 500 years ago. In this case, death occurred at the top of an Andean mountain where the body swiftly froze, preserving the brain.

However, Seyitömer Höyük - the Bronze Age settlement in western Turkey where this brain was found - is not in the mountains. So how did brain tissue survive in four skeletons dug up there between 2006 and 2011?

Meriç Altinoz at Haliç University in Istanbul, Turkey, who together with colleagues has been analysing the find, says the clues are in the ground. The skeletons were found burnt in a layer of sediment that also contained charred wooden objects. Given that the region is tectonically active, Altinoz speculates that an earthquake flattened the settlement and buried the people before fire spread through the rubble.

The flames would have consumed any oxygen in the rubble and boiled the brains in their own fluids. The resulting lack of moisture and oxygen in the environment helped prevent tissue breakdown.

A group of archeologists have made a significant discovery in Turkey, unearthing an ancient Roman column piece touted as the largest of its kind. Ataturk University's archeology team brought to light on Friday a colossal Corinthian capital measuring 1.9m in diameter and 2.5 m in height in Erdek district.

"This is the largest and most exquisite Corinthian capital built within the territory of the Roman Empire," said team head Nurettin Kochan. The piece is crafted in the Corinthian order, chronologically the latest of three recognized ancient Roman architectural styles. It was found at the site of Kyzikos Hadrian Temple where excavation work has continued since August 15. Kochan said the discovery bore significance on a global scale and would contribute to Turkey's tourism sector.

He said the dimensions of the capital surpass those at the world-renowned Baalbek Temple in Lebanon, among the best preserved Roman temple sites.

"There's no other capital of this size in the Corinthian order," he said. "Kyzikos Hadrian Temple outshines even the Baalbek Temple of Jupiter in Lebanon, considered the largest and most spectacular Corinthian temple in the world."

Kochan said they have also found large pieces of frieze decorated with reliefs featuring larger-than-life representations of human, eagle and bull figures. Hadrian Temple is similar in size to the Temple of Artemis in the ancient city of Ephesus and the Temple of Apollo in Didim, both located in Turkey's Aegean region.

The excavations, carried out by a team consisting of university professors, grad and undergrad students and dozens of workers, will continue until October 8.

The U.S. has a long history of unleashing chemical and biological warfare against civilians both abroad and at home, primarily as an experiment but also to get rid of outdated stockpiles while inventing a villain to crucify. Canadian author Robert Rodvik rips into Barack Obama for hypocritically warning Syria against its alleged use of chemical weapons and lambastes his own country which, from a potential U.S. target, turned into a U.S. accomplice in the chemical warfare waged against the Vietnamese people.

It was lost for so long that it had assumed mythical status for art historians. Some doubted whether it even existed.
But a 500-year-old mystery was apparently solved today after a painting attributed to Leonardo da Vinci was discovered in a Swiss bank vault.

The painting, which depicts Isabella d'Este, a Renaissance noblewoman, was found in a private collection of 400 works kept in a Swiss bank by an Italian family who asked not to be identified.

It appears to be a completed, painted version of a pencil sketch drawn by Leonardo da Vinci in Mantua in the Lombardy region of northern Italy in 1499.

A stash of jewelry predating the 13th-century Mongol invasion has been discovered at an excavation site in the central Russian city of Ryazan, an archeologist said Wednesday.

The treasure trove, unearthed in an old artisan district, contained 80 pieces of jewelry - including bracelets, necklaces and tiaras - as well as jewelry-making tools and raw gold and silver ingots.

"It is the 17th such treasure trove found in Old Ryazan," said Igor Strikalov of the Russian Institute of Archeology.

In the Kurdistan region of northern Iraq archaeologists have discovered an ancient city called Idu, hidden beneath a mound.

Cuneiform inscriptions and works of art reveal the palaces that flourished in the city throughout its history thousands of years ago.

Located in a valley on the northern bank of the lower Zab River, the city's remains are now part of a mound created by human occupation called a tell, which rises about 32 feet (10 meters) above the surrounding plain. The earliest remains date back to Neolithic times, when farming first appeared in the Middle East, and a modern-day village called Satu Qala now lies on top of the tell.

The city thrived between 3,300 and 2,900 years ago, said Cinzia Pappi, an archaeologist at the Universität Leipzig in Germany. At the start of this period, the city was under the control of the Assyrian Empire and was used to administer the surrounding territory. Later on, as the empire declined, the city gained its independence and became the center of a kingdom that lasted for about 140 years, until the Assyrians reconquered it. [See Photos of Discoveries at the Ancient City of Idu]