Strange Clouds Spotted at the Edge of Space

A weirdly wonderful sight appeared to astronauts aboard the International Space Station this summer — thin blue clouds hovering at the boundary between Earth's atmosphere and the void.

The noctilucent or "night-shining" clouds are at an altitude of 47 to 53 miles (76 to 85 km), where meteors and bright aurora lights are not uncommon and the atmosphere gives way to the blackness of space. The clouds remain a scientifically baffling phenomenon more than 120 years after their discovery.

"It's lovely," said Gary Thomas, an atmospheric scientist at the University of Colorado after looking at a photo taken from the space station. "And it shows just how high these clouds really are – at the very edge of space."

The clouds form at dizzying heights where the air is one hundred million times drier than the Sahara. By contrast, the common high-altitude cirrus clouds only reach heights of 11 miles (18 km) up.

"We have a fairly good idea that the water vapor from below gets transported upwards," Thomas told SPACE.com. "That is in essence the fuel."

Part of that water vapor comes from rising air in the tropics, where a few parts per million of water escape into farthest reaches of the upper atmosphere. Another likely source of water vapor is methane oxidation. Methane concentrations have more than doubled over the past 100 years, which could explain part of the changes in the high-flying clouds over the past decades.

People first spotted the noctilucent clouds a few years after the 1883 eruption of the Krakatoa super-volcano in Indonesia created spectacular sunsets from ash in the atmosphere. Robert Leslie of Southampton, England saw the clouds one evening in July 1885 and published the first observations in the journal Nature.

The clouds have since spread from the northern latitude regions such as Scandinavia, Scotland and Siberia to areas farther south. Sightings have cropped up in Washington and Oregon in the United States, as well as in Turkey and Iran.

Scientists can observe widespread instances of the clouds throughout the polar summer. Some clouds even formed after the fateful launch of the doomed space shuttle Columbia, when 400 tons of water from the shuttle exhaust drifted toward the South Pole.

The mystery only thickened after the launch of a satellite dubbed Aeronomy of Ice in the Mesosphere (AIM) in 2007, when AIM spotted a type of "stealth" noctilucent cloud made of smaller ice crystals less than 30 nanometers (a red blood cell is about 10,000 nanometers). Such clouds appear to stay in the upper atmosphere all the time.

"They're just so tiny that they don't scatter light efficiently," Thomas said.

AIM has also found a strong resemblance between the noctilucent clouds and tropospheric clouds that hover near Earth's surface, which suggests that the dynamics of near-space weather may not be incredibly strange after all.

Researchers speculate that the origin and spread of the clouds is linked to patterns of climate change associated with the modern era. But they are not ruling out a host of other possible factors, including methane, carbon dioxide, the number of meteors seeding the upper atmosphere, and even the 11-year sunspot cycle.

"I think the jury's still out on that," Thomas said. "We're just trying to understand now how clouds form and how they vary."

Human geography is mapped in the genes

The genes of a European person can be enough to pinpoint their ancestry down to their home country, claim two new studies.

By reading single-letter DNA differences in the genomes of thousands of Europeans, researchers can tell a Finn from a Dane and a German from a Brit. In fact a visual genetic map mirrors the geopolitical map of the continent, right down to Italy's boot.

"It tells us that geography matters," says John Novembre, a population geneticist at the University of California, Los Angeles, who led one of the studies. Despite language, immigration and intermarriage, genetic differences between Europeans are almost entirely related to where they were born.

This, however, does not mean that the citizens of each European nation represent miniature races. "The genetic diversity in Europe is very low. There isn't really much," says Manfred Kayser, a geneticist at Erasmus University Rotterdam in the Netherlands, who led the other study.

One-letter differences

Kayser's and Novembre's teams uncovered the gene-geography pattern only by analysing hundreds of thousands of common gene variants called single nucleotide polymorphisms (SNPs) across the genomes of people from about two dozen countries. SNPs are places in the genome where one person's DNA might read A, while another's T.

Though the teams worked independently, they used some of the same DNA samples, which were gathered by the pharmaceutical company GlaxoSmithKline to help hunt for genes linked to drug side effects. The researchers recorded the results alongside the country of origin for each subject as well as that of their parents and grandparents when possible.

For each subject, the researchers decoded half a million SNPs. However, to get an overall assessment of the difference between any two genomes, the researchers used a mathematical trick that scrunched the hundreds of thousands of SNPs into two coordinates, with each person's genome represented by a point. The greater the distance between two points, the greater the difference in their genomes.

When both teams plotted thousands of genomes on a single graph along with their country of origin, a striking map of Europe emerged. Spanish and Portuguese genomes clustered "south-west" of French genomes, while Italian genomes jutted "south-east" of Swiss.

These cardinal directions are artificial, but the spatial relationships between genomes are not. In general, the closer together two people live, the more similar their DNA. The same is known to be true of animals .

Predicting origins

The map was so accurate that when Novembre's team placed a geopolitical map over their genetic "map", half of the genomes landed within 310 kilometres of their country of origin, while 90% fell within 700 km.

Both teams found that southern Europeans boast more overall genetic diversity than Scandinavians, British and Irish.

"That makes perfect sense with the major migration waves that went into Europe," says Kayser, noting Homo sapien's European debut 35,000 years ago, post-ice age expansions 20,000 years ago, and movements propelled by the advent of farming 10,000 years ago. In each case, members of established southern populations struck north.

"A pattern in which genes mirror geography is essentially what you would expect from a history in which people moved slowly and mated mainly with their close neighbours," says Noah Rosenberg, a geneticist at the University of Michigan in Ann Arbor.

Bodies found in the tomb of 'boy king' Tutankhamun's tomb are twin daughters

Two foetuses found buried with Tutankhamun may have been his twin daughters, an expert has claimed.

Professor Robert Connolly, an anatomist who is working with Egyptian authorities to analyse the tomb of the Egyptian Pharaoh, says that preliminary tests on the mummified remains of the two still-born babies indicate that Tutankhamun may have fathered them both. He will present the new findings at the Pharmacy and Medicine in Ancient Egypt Conference at the University of Manchester today.

Professor Connolly, who first studied the remains of Tutankhamun in the Sixties, said: “The two foetuses in the tomb of Tutankhamun could be twins, despite their very different size and thus fit better as a single pregnancy for his young wife [Ankhesenamun]. This increases the likelihood of them being Tutankhamun's children.”

“I studied one of the mummies, the larger one, back in 1979, determined the blood group data from this baby mummy and compared it with my 1969 blood grouping of Tutankhamun. The results confirmed that this larger foetus could indeed be the daughter of Tutankhamun.

“Now we believe that they are twins and they were both his children.”

Professor Connolly, a physical anthropologist at the University of Liverpool, said: “It is a very exciting finding which will not only paint a more detailed picture of this famous young king's life and death, it will also tell us more about his lineage.”

The foetuses have been stored at the Faculty of Medicine in Cairo University since the archaeologist Howard Carter discovered them in the teenage king's tomb on the west bank of Luxor in 1922. Egyptologists have long debated whether they were his children or if they were placed in the tomb with the symbolic purpose of allowing the famous pharaoh to live on as newborns in the afterlife.

The answer to this hereditary puzzle is closer because the two foetuses are to undergo CT scans and DNA testing to determine possible diseases and their relation to Tutankhamun. The smaller foetus is about five months in gestational age and the larger foetus is estimated to be between seven and nine months. The results of the remaining tests are due in December.

“We are very proud to have Professor Connolly speaking at the conference and are extremely excited about his new findings,” said the conference director Rosalie David, of the University of Manchester's Faculty of Life Sciences.

“Tutankhamun is such an important figure in Egyptology. He was a fascinating character whose tomb and indeed body has given us so much information about life in Ancient Egypt, and it seems that he will continue to do so for some time yet.”

More than 100 delegates from ten countries will be attending the conference. It intends to bring together the two elements of Ancient Egyptian healthcare practices — pharmacy and medicine