Draught on Mars
The lack of liquid water on the surface of Mars today has been demonstrated by new evidence in the form of meteorites on the Red Planet examined by an international team of planetary scientists.
In a study led by the University of Stirling, an international team of researchers has found the lack of rust on the meteorites indicates that Mars is incredibly dry, and has been that way for millions of years.
The discovery, published in Nature Communications, provides vital insight into the planet's current environment and shows how difficult it would be for life to exist on Mars today.Mars is a primary target in the search for life outside Earth, and liquid water is the most important pre-requisite for life.
Dr Christian Schröder, Lecturer in Environmental Science and Planetary Exploration at the University of Stirling and Science Team Collaborator for the Mars Exploration Rover Opportunity mission, said:
“Evidence shows that more than 3 billion years ago Mars was wet and habitable. However, this latest research reaffirms just how dry the environment is today. For life to exist in the areas we investigated, it would need to find pockets far beneath the surface, located away from the dryness and radiation present on the ground."
Smallest Magnifying Glass
For centuries, scientists believed that light, like all waves, couldn't be focused down smaller than its wavelength, just under a millionth of a metre. Now, researchers led by the University of Cambridge have created the world's smallest magnifying glass, which focuses light a billion times more tightly, down to the scale of single atoms.
In collaboration with colleagues from Spain, the team used highly conductive gold nanoparticles to make the world's tiniest optical cavity, so small that only a single molecule can fit within it. The cavity -- called a 'pico-cavity' by the researchers -- consists of a bump in a gold nanostructure the size of a single atom, and confines light to less than a billionth of a metre. The results, reported in the journal Science, open up new ways to study the interaction of light and matter, including the possibility of making the molecules in the cavity undergo new sorts of chemical reactions, which could enable the development of entirely new types of sensors.
According to the researchers, building nanostructures with single atom control was extremely challenging. "We had to cool our samples to -260°C in order to freeze the scurrying gold atoms," said Felix Benz, lead author of the study. The researchers shone laser light on the sample to build the pico-cavities, allowing them to watch single atom movement in real time.