Planetary scientists have discovered the highest clouds above any planetary surface. They found them above Mars using the SPICAM instrument on board ESA’s Mars Express spacecraft. The results are a new piece in the puzzle of how the Martian atmosphere works, EureKalet wrote.
Until now, scientists had been aware only of the clouds that hug the Martian surface and lower reaches of the atmosphere. Thanks to data from the SPICAM Ultraviolet and Infrared Atmospheric Spectrometer onboard Mars Express, a fleeting layer of clouds have been discovered at an altitude between 80 and 100 kilometers. The clouds are most likely composed of carbon dioxide.
SPICAM made the discovery by observing distant stars just before they disappeared behind Mars. By looking at the effects on the starlight as it traveled through the Martian atmosphere, SPICAM built up a picture of the molecules at different altitudes. Each sweep through the atmosphere is called a profile.
The first hints of the new cloud layer came when certain profiles showed that the star dimmed noticeably when it was behind the 90Ð100 kilometer high atmospheric layer. Although this happened in only one percent of the profiles, by the time the team had collected 600 profiles, they were confident that the effect was real.
“If you wanted to see these clouds from the surface of Mars, you would probably have to wait until after sunset“ says Franck Montmessin, a SPICAM scientist with Service d’Aeronomie du CNRS, Verri�res-le-Buisson, France, and lead author of the results. This is because the clouds are very faint and can only be seen reflecting sunlight against the darkness of the night sky. In that respect, they look similar to the mesospheric clouds, also known as noctilucent clouds, on Earth. These occur at 80 kilometers altitude above our planet, where the density of the atmosphere is similar to that of Mars’ at 35 kilometres. The newly discovered Martian clouds therefore occur in a much more rarefied atmospheric location.
At 90Ð100 kilometers above the Martian surface, the temperature is just Ð193¡ Celsius. This means that the clouds are unlikely to be made of water. “We observe the clouds in super-cold conditions where the main atmospheric component CO2 (carbon dioxide), cools below its condensation point. From that we infer that they are made of carbon dioxide,“ says Montmessin.
But how do these clouds form? SPICAM has revealed the answer by finding a previously unknown population of minuscule dust grains above 60 kilometers in the Martian atmosphere. The grains are just one hundred nanometers across (a nanometer is one thousand-millionth of a meter).

The dwarf galaxies are thought to be the building blocks of large galaxies, such as our own Milky Way. (Google Photo)

A further four satellite galaxies of the Milky Way have been discovered, bringing the amount known to around 20, New Scientist magazine reported on Monday.
The discoveries were made by a team led by Vasily Belokurov of the University of Cambridge, UK.
The satellites are named after the constellations in which they were found--Coma Berenices, Canes Venatici II, Hercules, and Leo IV.
Astronomers used new observing techniques and detailed sky maps including the Sloan Digital Sky Survey (SDSS) to look for the galaxies.
The largest and smallest galaxies are Hercules and Coma Berenices, which are about 1,000 and 200 light years across, respectively.
Like most of the other dwarfs discovered by SDSS, the finds are much smaller and fainter than the dwarfs that were known previously, according to Belokurov, who was quoted as saying, “They should not really be called dwarfs-- they are more like hobbits.“
The dwarf galaxies are thought to be the building blocks of large galaxies, such as our own Milky Way, which is about 100,000 light years wide.
The pace of discoveries suggests that many more such satellites remain unknown, which would present a serious challenge to models of dark matter as “warm“, fast-moving particles.
Based on the number of dwarf galaxies SDSS has found so far, the researchers estimate that there may be something in the region of 50 small satellites around the Milky Way.

Nanoscale “guitar strings“ that vibrate at more than one billion times per second could detect and identify individual molecules. The device may even let researchers study the quantum behavior of molecules, and possibly even viruses.
According to NaturalScience, a group led by Alex Zettl, a condensed matter physicist at the University of California, Berkeley, US, used electron-beam lithography and reactive ion etching to create a trench 300 nanometers across with electrodes on either side and a chargeable plate at the bottom.
The researchers then coaxed carbon nanotubes to grow across the gap. Driven by high-frequency signals, the tiny bridges resonate at 1.3 billion cycles per second, or 1.3 gigahertz.
“Other groups have made resonators that were very small, and have gotten into the one gigahertz regime, but only at very low temperatures and pressures,“ says Zettl. “So getting these very high frequencies under room temperature and atmospheric pressure is a real breakthrough.“
Zettl credits their success in part to the use of carbon nanotubes, which have low mass, ultra-high stiffness and few defects, making them ideal high-frequency oscillators. “No other material known has the same combination of good properties,“ he says.
The technique works because strings of a certain mass should vibrate at a particular resonant frequency. Change the mass and the frequency changes as well, just as a heavy guitar string vibrates at a lower frequency than a lighter one. The change in frequency can be spotted by adding the signal to a known test frequency.
In addition, the team measured the nanotubes’ oscillations in a novel way. Instead of mixing the signal from the nanotubes’ vibrations into a test current alternating at a similar frequency, they used a signal at twice the resonant frequency. The result was a much sharper measurement. “It’s like a souped-up radio system,“ says Zettl. “When you work through the mathematics, you get very, very high sensitivity.“
And it is that high sensitivity that lets them detect the how a test mass placed on the string causes it to vibrate more slowly. The device can detect masses of just 10-18 grams. “This is where you can measure molecules,“ says Zettl.
The Berkeley group’s next goal is to develop coatings for the carbon nanotubes that will selectively bind target molecules, such as explosives, so that they can actually start spotting molecules. “In principle, if you get things to stick on selectively, you could do detection with sensitivity and specificity,“ Zettl explains. He hopes to demonstrate this in the lab within a year.

A boy rests during a weight-losing summer camp in Wuhan, central China's province, July 13. (Reuters File Phto)

Everyone knows that obesity is unhealthy, but now a new study shows that being obese in midlife dramatically increases your risk of dying early, HealthDay said.
“People who are overweight have a moderately increased risk of premature death, and people who are obese have a greatly increased risk of premature death,“ said lead researcher Dr. Michael Leitzmann, an investigator at the National Cancer Institute.
In the study, Leitzmann’s group collected data on 527,265 men and women who were 50 to 71 years old in 1995 and 1996. Over 10 years of follow-up, the researchers looked at the relationship of weight to the risk of dying.
Through 2005, there were 61,317 deaths among those in the study. Leitzmann’s team found that people who were overweight when they were 50 had a 20 percent to 40 percent increased risk of dying prematurely. For those who were obese, the risk of premature death was two to three times that of normal-weight people. “That translates into a 200 to 300 percent increase in the risk of premature death,“ Leitzmann said.
The researchers did not look at specific causes of death, but Leitzmann said the primary causes of premature death in this group were heart disease and cancer.
The advice to reduce the risk of premature death is obvious. “People need to maintain a normal weight throughout adulthood and avoid developing excess weight,“ Leitzmann said. “And if you are overweight or obese, lose the excess weight.“
One expert thinks this study highlights the risk of death from any weight gain.
“This study adds good and compelling evidence to our previous suspicion that being overweight is a risk factor for early death, not just being obese,“ said Dr. Tim E. Byers, a professor of preventive medicine at the University of Colorado School of Medicine and author of an accompanying commentary in the journal.
The advice is nothing new, Byers said. “Let’s watch our weight, especially for us baby boomers who have seen our weight creep up by a pound or two a year,“ he said. “Let’s turn that around, and take small steps to start losing weight.“
Another expert agreed that most diseases that shorten life can be laid at obesity’s door.
“We should not need another word to recognize obesity as one of the great public health threats of our time,“ said Dr. David L. Katz, director of the Prevention Research Center at Yale University School of Medicine.

A photographer take pictures of a replica of the Maxakalisaurus topai, similar to a large anteater, that is presented during a news conference by researchers from the Federal University of Rio de Janeiro, August 28. (Reuters Photo)

Brazilian paleontologists have discovered a new giant dinosaur species based on fossilized fragments of the herbivorous reptile that lived 80 million years ago, Reuters reported.
The Maxakalisaurus topai, of the Titanosauria group, was 13 meters (yards) long and weighed about nine tons.
It had a large body, long tail and neck with a relatively small head. Some of the bones found had the marks of teeth on them, which led scientists to believe that the specimen was devoured by carnivorous dinosaurs after its death.
The fossils date back to the Late Cretaceous period. They were found during excavations between 1998 and 2002 next to a highway in a place called Serra da Boa Vista in central-southern Minas Gerais state. It then took some time for the scientists to categorize the species and reconstruct the skeleton.
The name of the species, Maxakalisaurus topai, derives from an Indian tribe, Maxakali, which lives in the area. Topa is a divinity that the tribe worships. It is a custom in Brazil to give native Indian names to paleontological finds.
The find is extremely important as Maxakalisaurus topai is closely related to a highly evolved group of dinosaurs, called the Saltasaurinae, researcher Alexander Kellner said on Monday after presenting a reconstructed skeleton of the reptile in the National Museum in Rio de Janeiro .
The Saltasaurinae lived 70 million years ago and the fossils have only been found in Argentina.
“Among its specific traits are some peculiarities that we found in the vertebrae, especially a protuberating sacral vertebra ... It also has teeth with carinae (ridges), which we think served to better process the food,“ Kellner said.
Dinosaurs from the Titanosauria group were the main herbivorous dinosaurs of the ancient super-continent known as Gondwana, which grouped Australia, India, Africa, South America and Antarctica some 200 million years ago.
Some scientists believe a connection still existed between what is now South America, Antarctica, India and possibly Australia until about 70 million years ago.