With thanks to CSIRO Science by Email for this wonderful series of science updates. I like seeing my friend, Denise Hardesty, reported below, for her work on sea trash.
MOTH’S EYES MAKE BETTER SUNGLASSES
Despite their tendency to circle light bulbs, moths have eyes that are designed for darkness. Each eye has a bumpy pattern that stops light reflecting off the surface, possibly helping the moth see in the dark and hide from predators.
For years, scientists have been trying to replicate the effect. They hope that adding a similar pattern to electronic devices could prevent glare when sunlight hits your TV, computer screen or phone. It could also make solar panels more efficient by reducing how much light bounces off them, while stopping any dazzling reflections.
There’s been some success. Extremely tiny shapes, similar to those found in a moth’s eye, have been made using metals, silicon and plastics. Scientists at the University of California, Irvine, recently described how to etch a pattern of nano-sized cones on Teflon, the non-stick material famously found on frying pans.
After coating a thin film of Teflon with a layer of tiny polystyrene balls, they exposed it to a corrosive chemical. The polystyrene partially protected the Teflon, leaving millions of tiny nanocones etched into the surface. In the process, the Teflon film turned from transparent to white, a sign that light was being scattered. Then they added a thin layer of gold to the cones. To their surprise and, at first, concern, they noticed what looked like soot had appeared on the surface. In fact, the material had turned black and was antireflective, bouncing less than one per cent of incoming light.
As well as reducing glare, the aptly named black gold also conducts electricity and repels water. It seems the magnificent moth eye has much to teach us.
GHOST NETS AND TURTLES
There are seven threatened species of marine turtle and we have six of them here in Australia. One of the threats to turtle species is marine debris – waste that humans throw away that has made its way into the ocean. Waste affects turtles in two ways – either they mistake it for food, or they get tangled up in it
Ghost nets are fishing nets that have been lost or abandoned at sea. These nets continue to travel through the ocean, trapping and entangling turtles. These nets are very hard to escape from and can drift in the ocean for decades, catching protected turtles and other marine species.
Scientists from CSIRO are working with GhostNets Australia and Indigenous rangers to identify areas where turtles are most at risk. The researchers use models based on ocean currents to identify areas that are likely to have a high number of ghost nets in the Gulf of Carpentaria and to find out where turtles are most likely to get caught up in these nets. The team is also working with schools and citizen scientists to survey beaches for litter. The data will help them identify where efforts to clean up nets and marine debris will have the greatest impact.
CSIRO’s Dr Denise Hardesty is leading the research and says, “The best way to tackle marine debris is to stop it from entering our oceans. Together we can all make a difference.” Simple things such as recycling and picking up litter can go a long way in protecting the future of marine turtles!
An exploding star is called a supernova. The big blast can leave behind a pulsar, which is a kind of neutron star. A pulsar spins very fast and sends energy to Earth, in the form of radio waves. As the pulsar beam passes repeatedly over the Earth, like the spotlight of a lighthouse, the pulsar appears to be blinking.
A pulsar is sometimes known as the ‘clock’ of the universe. Just as the Earth spins on its axis every 24 hours, a pulsar spins at a constant speed. Scientists measure the speed of a pulsar by how often Earth receives a ‘pulse’ of radio waves.
With the help of CSIRO’s Parkes telescope, and another telescope in South Africa, a group of researchers noticed that one pulsar was spinning slower than usual. The pulsar is located in the constellation of Puppis and is estimated to be 37 000 light-years from Earth. One possible explanation for the decrease in speed is that a large rocky object – such as an asteroid – hit the pulsar. Scientists estimate that the asteroid weighed a billion tonnes and could have been created when the star exploded!
CSIRO’s Dr Ryan Shannon suggests that the pulsar may have reacted to the collision by zapping the asteroid, causing it to vaporise. The vaporised particles that are left behind are electrically charged. These particles cause the pulsar to spin more slowly, changing the shape of the radio waves received by Earth.
It has been said that time heals all wounds. The ‘clock’ of the universe is expected to return to its original spinning speed once those pesky particles pass!
Just as plants grow and develop, so does technology. The combination of these two fields has given rise to ‘nanobionics’. This exciting field could lead to pollution-free machines and a better understanding of our environment.
Plants make their own food by photosynthesis, a process which takes place in tiny sub-units of cells called ‘chloroplasts’. A team of researchers from the Massachusetts Institute of Technology inserted nanoparticles into the chloroplasts of plants, boosting their ability to capture light energy. As well as supercharging photsosynthesis, the researchers discovered a second superpower – the treated plants glowed when exposed to infra-red light!
The team also noticed that the glow stopped when the plant was exposed to nitric oxide – a pollutant commonly produced by cars. The plants acted as chemical sensors, the glow fading in response to the pollutant.
Professor Michael Strano, lead researcher of the study, foresees wide application of bionic plants in our society. He hopes that nanoparticle technology will enable plants to produce energy for other functions – limited only by our imagination.
While there is still more research to be done, our future looks brighter, safer and greener. It won’t be long before bionic plants are lighting up our streets and monitoring our environment!
It was found by accident. “I was actually trying to use a mould [casting] process to make a really nice flat lens,” says Steve Lee, a physicist and engineer at the Australian National University. “It didn’t work very well, I was very disappointed. At the same time I left a drop in the oven overnight and it formed a really nice curvature.”
Tough and rubbery, the drop had some interesting properties, but Steve didn’t think much of it until he talked to Tri Phan, a doctor working in the microscopy division at Sydney’s Garvan Institute of Medical Research. “He got excited,” says Steve.
The lens simply sticks onto a smartphone camera to provide instant magnification. Steve is now talking to dermatologists who think this tiny lens could track suspicious moles in case they change shape. Farmers could use it to identify pests, perhaps uploading photos to biosecurity agencies.
There are several ways to make a lens. Steve’s process uses only an oven and a polymer called polydimethylsiloxane, the strong, scratch-resistant material found in soft contact lenses. A drop is placed on a glass microscope slide and flipped upside down. Gravity and surface tension pull the droplet into the shape of a lens
After the accidental discovery, Steve wanted to make the lens better. “I thought maybe I could try layering. I did it again and again until I had refined the time, the sequence steps, how much to drop … Each drop reduces the focal length and increases the magnifying power,” says Steve. “The highest magnification strength we can get is 160 times, resolving four micron [four thousandths of a millimetre] structures.”
The lenses might find use in developing countries as they cost only a cent in material and all you need to make them is an oven. Steve says they are so easy to make you could do it at home. He suggested you could make one with gelatine by experimenting with different viscosities, and it works! See this week’s activity to make your own jelly lens and try sticking it on a smartphone.