With thanks to the CSIRO Science by Email
The Galactic Neighbourhood
An invisible brown dwarf has been found a mere 7.2 light years away, by space telescopes searching in the infrared.
On a dark night, the sky sparkles with stars beyond counting, but even the darkest night cannot reveal every object above. It took two space telescopes to spot the star-like object called WISE J085510.83-071442.5, which is thought to be a brown dwarf.
At only 7.2 light years away, it takes the title of the fourth-closest system to the Sun. Our closest star, Proxima Centauri, is just 4.2 light years away by comparison.
Our newly-found neighbour is very good at hiding. Brown dwarfs do not have enough mass to fuse hydrogen into helium, so they don’t produce lots of visible light energy like larger stars do. This new object is invisible to us. But it does produce another kind of light – infrared. We can’t see it, but infrared sensors can. The hidden brown dwarf was revealed by two NASA space telescopes, the Wide-field Infrared Survey Explorer (WISE) and the Spitzer Space Telescope.
There are plenty of reasons to be excited about our new neighbour. It is the coldest brown dwarf ever found, with a temperature between –48 and –13 degrees Celsius. That’s similar to the North Pole! It is also particularly tiny, estimated to be three to ten times the mass of Jupiter.
At that size, it could be a gas giant planet that has lost its star system. Kevin Luhman, who discovered the object, believes it is more likely to be a brown dwarf because they are known to be fairly common. Kevin also found the third-closest system to the Sun, a pair of warmer brown dwarfs.
“It is remarkable that even after many decades of studying the sky, we still do not have a complete inventory of the Sun’s nearest neighbours,” said Michael Werner, from NASA’s Jet Propulsion Laboratory, in the press release. “This exciting new result demonstrates the power of exploring the Universe using new tools, such as the infrared eyes of WISE and Spitzer.”
After thousands of years of looking with eyes, and hundreds with telescopes, it seems space still has plenty of surprises.
18 May 2014, is International Museum Day. To celebrate, we’re taking a look at the Australian National Biological Collections managed by CSIRO, which are being unlocked for digital access by community.
‘Museum collections make connections’ – that’s the theme for International Museum Day 2014. Today, people are connecting to museum collections not just in person, but on laptops, smartphones and other devices.
“Museums represent historical collections that can’t be duplicated,” says John La Salle, Director of the Atlas of Living Australia at CSIRO. “They contain biodiversity knowledge that can’t be recollected.”
CSIRO maintains collections of plants, animals and other organisms on behalf of Australia. They are available to support research by scientists around the world. But for people in remote areas and overseas, visiting these collections can be expensive.
John was part of a team that recently created a way to make 3D models of insects in their natural colours using simple equipment. An insect is mounted on a printed mat, and the pin is glued to a magnet. The magnet holds the insect to a turntable, which can be rotated and tilted side to side. It is photographed at different angles, and the pictures are combined using software to create a detailed digital 3D model.
A 3D computer model is easier to share online and you can get an accurate picture of the whole specimen. “When you are trying to identify an insect, you want to be able to flip it around and look at it from different angles,” says John.
So far, the team has made 3D images of a handful of insect specimens to show the idea works. Now the question is how make 100 images, and then 1000. There’s plenty to digitise – with around 12 million specimens, the Australian National Insect Collection in Canberra is the world’s largest collection of Aussie insects.
Unlocking the insect collection to an online space opens up a huge range of uses, such as identifying plant pests. “You can see the advantage of making these pictures available on handheld devices for quarantine officials,” says John. “There’s a variety of uses for collections, some of which we can’t even imagine. That’s the exciting part, when people start using the collections in ways we hadn’t expected.”
The eyes have it. Bright, colourful butterflies and birds easily catch our attention. But to visualise bacteria, we need to get creative.
Molecular biologist and artist David Goodsell, makes watercolour paintings of bacteria, living things you can’t see without a microscope. He is a legend in the field. Mycoplasma mycoides, a bacterium that causes lung disease in cows, is painted with a brilliant green membrane that brings grass to mind. Inside, bright yellow DNA curls next to protein-builders in purple and blue.
It’s not just a pretty picture. The molecules are not only in the right place, but in the right amounts and with their actual shape based on research. A lot of work goes into each painting, giving us a new way to visualise bacteria. Chock-full of the molecules of life, the picture is as busy, detailed and connected as indeed a cell must be.
You could say that seeing bacteria is more important than watching birds or butterflies. After all, those microscopic bugs make us sick. But before you reach for the antibiotics, not all bacteria are bad news. Bacteria in our gut keep us healthy. In fact, they are more like invisible friends than foes.
Inspired by David’s paintings, CSIRO recently created The Hungry Microbiome, an animation that introduces us to the bacteria in our gut. These hungry fellows chow down on resistant starch and produce the chemical butyrate, the same short-chain fatty acid that gives parmesan cheese its smell. Butyrate feeds the human cells in our gut, and keeps our bowels healthy.
In the animation, green bacteria chomp at balls of starch and release colourful fatty acids, which fall on human cells like gentle rain. By showing us a vision of the unseen world inside our gut, this animation says more than words ever could.
Australians eat more fibre than Americans, yet our rate of bowel cancer is still among the highest in the world. Research suggests that it is resistant starch we should be eating to prevent bowel cancer. “We have a compelling story founded on decades of research,” says Sean O’Donoghue, CSIRO. “We worked closely with [bowel health researcher] David Topping and other scientists to ensure everything in the animation is based on evidence.”
We are often told what we should and shouldn’t eat. It’s easy to tune out, to think ‘whatever.’ Animations like these can save lives, because they don’t just tell us, they show us.
Perfumes for Pests
Cross-species communication between citrus plants, bacteria, jumping plant lice and wasps begins with a fresh, minty smell.
Jumping plant lice, Diaphorina citri, are small insects that eat the sap of citrus trees like oranges and lemons. As they suck on tree blood, the plants produce the minty smell of wintergreen oil.
Wintergreen oil, or methyl salicylate, is also used in some toothpastes and mouthwash. But the smell on a tree seems to tell passing lice that a feast is on. Wintergreen oil can attract crowds of jumping plant lice, and that causes big headaches for the agriculture industry.
Australia is lucky to be free of jumping plant lice. Curiously, a century ago these lice were in the Northern Territory – there are sap-sucking specimens from Australia in the collection at the Natural History Museum in London. But when scientists went back to the Northern Territory in 2002, they couldn’t find any sign of the plant lice anywhere.
Jumping plant lice are bad news because they don’t just suck plant sap; they also spread bacteria. Candidatus Liberibacter asiaticus causes citrus greening disease which weakens and kills trees. The bacteria have a neat trick to infect new plants. They attract plant lice to infected trees by making the trees produce minty wintergreen oil. The lice fly in and land for a taste. When they fly away again, the bacteria hitch a ride and spread to more trees.
Another insect is attracted by the smell of wintergreen oil – a small, parisitoid wasp. Tamarixia radiate lays its eggs underneath young jumping plant lice, so when a new wasp hatches it has a lice meal ready. The wasp is attracted to the smell produced by trees infected by bacteria to attract lice. Phew!
Unravelling this complicated web is a team at the Citrus Research and Education Center at the University of Florida. They tested how wasps behaved when exposed to natural plant odours, caused by either bacteria or munching plant lice. Then the scientists compared the effect of using pure methyl salicylate (wintergreen oil), a lemony smell, a flowery smell and no smell at all.
Wasps prefer wintergreen. Many of us like communications delivered with minty freshness, but it’s amazing that complex communication across species can happen with a single, scented message.
The first pterosaur eggs that were preserved in three dimensions have been found in China, giving us a glimpse into the lives of flying reptiles.
Pterosaurs were flying reptiles, and ruled the skies in the Jurassic and Cretaceous periods millions of years ago. Today, scientists share insights into how pterosaurs behaved, announcing a huge find of at least 40 fossilized individuals, along with five eggs beautifully preserved in three dimensions.
It’s the eggs that are the star of the show. Until now, only a few flattened pterosaur eggs had been found – this is the first time they’ve have been found in three dimensions. The fossils have a thin eggshell around a membrane. They seem to have been a bit squishy, similar to snake eggs today.
“It’s quite remarkable,” says John Long, a paleontologist at Flinders University, who was not involved in the study. “It’s one of the best preserved pterosaurs I’ve ever seen, and more importantly it’s got the eggs preserved in three dimensions. That’s very unusual for the age.”
Scientist Xiaolin Wang at the Chinese Academy of Science says the pterosaurs may have died in a storm 120 million years ago, based on the sediments found in the area. The fossil find comes from Turpan-Hami Basin in Xinjiang, China. “China has some of the best fossil sites in the world for fossils of this age, including the spectacular feathered dinosaurs and beautiful preservation of Early Cretaceous animals and plants,” says John. “It is a wonderful treasure trove, China. All sorts of interesting things are coming out of there. This is just another example of exquisite preservation that comes from that region.”
These particular pterosaurs are a new species, Hamipterus tianshanensis. Although 40 individuals have been identified, there might be up to a hundred preserved in the rocks. Finding fossils of so many individuals and eggs from different nests suggests these pterosaurs lived in large groups.
The researchers may have also found a difference in how male and female pterosaurs looked. All had crests on their heads, but they varied in size and shape. The scientists think males had larger and thicker crests, much like modern roosters sport a big red comb on their heads.
A whispering gallery of light has made the world’s most sensitive thermometer yet.
This thermometer sets a new record in precision. Made by an Australian team of researchers, it is three times better than the previous record holder, and can measure temperature differences of just 30 billionths of a degree. This is the smallest change which can currently be measured.
Although the thermometer is very precise, it is not accurate – it measures changes in temperature, not an absolute temperature. It can’t tell you that it is 20 degrees Celsius today, but it can tell you that a chemical reaction has produced energy! Scientists use these measurements to investigate how medicines react with chemicals in the body.
The thermometer works like a whispering gallery. Maybe you’ve played with one before. A whispering gallery is a curved wall, and when you whisper to one end the sound carries all the way across to the other. There’s a great example at the Barossa Reservoir in South Australia.
Instead of sound and a wall, the thermometer uses light and a crystal. Lasers fire red and green light into a crystal shaped like a Frisbee. The light circles ‘round and ‘round the disc, like sound in a whispering gallery.
Heat makes the crystal expand. That changes the speed of the red and green light. If the lights were sounds, the two tones would be slightly out of tune with each other. Because they are lights, the change in speed as they circle means a change in colour, which can be measured.
“We have built a very precise thermometer, and our technique could be used to measure other things,” explains Andre Luiten from the University of Adelaide. “Force, pressure or small quantities of molecules could be detected … We can use the power of light to do many useful things.”
The whispering gallery technique can detect a single virus in a drop of water. To do this, a round crystal is coated with chemicals that stick to a certain kind of virus. When a virus gets stuck, it changes the size of the crystal. Just like with the thermometer, this affects light in a way that can be measured.
One issue with the virus sensors is that they are sensitive to temperature. The thermometer team used this issue to their advantage – being sensitive to temperature is just what you want in a thermometer!
Humans produce a lot of waste, from flushing toilets to mining metals, like the copper in electrical wires that power computers, phones and tablets. To clean up our act, a new way to purify contaminated wastewater from mines has been developed by CSIRO scientists.
At a copper mining site in Queensland, the first demonstration of the new ‘Virtual Curtain’ treatment turned 50 million litres of acidic waste into rainwater quality water, which was safely discharged into a river.
“Since Roman times, lime has been the material of choice for neutralising acid waste,” says Grant Douglas from CSIRO. “This is a new technique to make a mineral from the contamination in solution. We can remove a wide range of contaminants in a single step.”
The Virtual Curtain treatment separates contaminated wastewater into two products – cleaner water and a fine sludge. This is not unique: sludge-producing lime treatments are used in mines around the world. The big advantage of the Virtual Curtain treatment is that it removes more contaminants. It also produces a much more concentrated sludge. So each litre of Virtual Curtain sludge contains much more metal and other contaminants than a litre of lime sludge.
“The concentration of contaminants in the material is so rich, it can form an ore and can be re-mined,” says Grant. Companies can turn their waste into wealth, money back for the cost of environmental treatment.
The Virtual Curtain treatment works by carefully balancing the conditions of the water. Scientists analyse the waste, and then add one or two chemicals and neutralise the acid, raising the pH to around 10. Once the conditions are just right, minerals in the water form hydrotalcites. Hydrotalcites are crystals that can incorporate a wide range of contaminants. Plus, they’re solid, so they drop out of the water and fall to the bottom, taking the trapped contaminants with them.
Grant says mining companies in Australia, Europe and the USA have contacted him and are interested in using the technique. It’s Australian research, made commercial by an Australian company, and taken to the world.
10 Years of Saturn
On the largest moon of Saturn, the hills are named after hobbits and elves, and the lakes after lakes on Earth. Titan is, in many ways, the most Earth-like world we’ve ever found.
Titan is a bitterly cold world covered in an orange haze. At around 180 degrees Celsius below zero, Titan is far too cold for liquid water. But beneath the smog lie rivers, lakes and seas, full of liquid ethane and methane. At home, methane is used for gas cooking. On Titan, methane seems to cycle from lakes to clouds like water does on Earth.
The spacecraft Cassini and the Huygens probe arrived at Saturn on 30 June 2004, ten years ago on Monday. In those ten years, Cassini has made over 100 flybys of Saturn’s moons. The most recent one bounced radio waves off Titan’s lakes. In April, it zoomed close enough to ‘sniff’ Titan’s atmosphere and take a chemical sample.
Last month, scientists looked at sunsets on Titan and found the orange smog affects blue light more than red light. This technique could help us understand planets beyond our solar system, the exoplanets. By watching an exoplanet as it moves between its star and Earth, scientists could learn about its alien atmosphere.
Late last year, scientists found the sea floor of Titan’s second largest sea, Ligeia Mare. Radar was able to pass through the pure liquid in the sea and bounce off the bottom. It turns out Ligeia Mare is 170 metres deep. That’s the same depth as Tasmania’s Lake St Clair, the deepest freshwater lake in Australia.
On Sunday, scientists shared a new study. Cassini’s radar had recorded a bright area in Ligeia Mare which later disappeared. Scientists think the bright area could have been a passing feature, like a wave, rising bubbles or something floating on the methane.
Perhaps this is a glimpse of the lake waking from a long winter. Seasons move slowly on Saturn’s moon. Titan’s northern hemisphere had its spring equinox in August 2009, and the summer solstice is not until May 2017.
In the warm tropical ocean around the Great Barrier Reef, the lionfish hunts. Venomous fins fan out to trap a school of smaller fish. The little fish look for an escape. But this lionfish is not hunting alone.
As we grow up, we learn to share, take turns and cooperate. Now it seems lionfish use the same skills for a more deadly purpose. New research shows lionfish hunt better when they cooperate with other lionfish, and that they share the meal evenly.
Lionfish are predators and use their long, stripy fins to corner prey. While working on the Great Barrier Reef, Oona Lönnstedt from James Cook University in Queensland noticed something strange. “I did a lot of observations at night and this is when I noticed how they seemed to hunt together in groups, spreading out their large pectoral (side) fins almost like fishermen with their nets”
Curious about the behaviour, Oona went back to the lab and used a maze-like aquarium to observe how lionfish behaved when there was prey around and a second lionfish nearby.
If the first lionfish found prey, it would swim to the second lionfish and do a display. It would put its head down and wriggle its tail fin. Then it slowly waved one side fin, and then the other side fin. The second lionfish almost always responded by waving back and following the first lionfish to hunt. If the second lionfish didn’t follow, the first one would come back and do the display again.
The two lionfish worked together to hunt by using their big side fins to herd the prey fish into a corner. The first lionfish, the one that started the hunt, usually took the first bite. After that they took turns and shared the feast evenly. This behaviour even happened when the two lionfish were different species, for example when a zebra lionfish partnered with an antennata lionfish.
Hunting as a team was very successful. When they were together, each lionfish ate more than they did when they hunted alone. Oona and the team think this complex hunting behaviour might be one reason why invasive species of lionfish are causing problems in the Caribbean. Their teamwork technique is killing too many prey fish, threatening the whole ecosystem.