In the science news this week: yawning is not contagious for autistic children, a new climate change report calls for substantial and sustained reductions in carbon dioxide emissions, Curiosity rover makes big water discovery, and finally, scientists discover a new form of matter that behaves a bit like a lightsaber.
Yawning not contagious for autistic children
Yawning is often contagious, but children with autism might miss facial cues that signal a yawn, according to a new study. While many people can’t help but yawn when someone around them does, this research suggests that this isn’t the case for everyone, according to Scientific American .
Tiredness, boredom and stress can all cause a yawn, but the contagious aspect of yawning is most interesting to researchers at the Department of Cognitive and Behavioral Science at the University of Tokyo. Participants in the study were presented with a video of a woman yawning, and researchers counted the number of yawns from the participants. To make sure the participants were paying attention, they were fitted with eye-tracking equipment so that the yawning video could be played when they were looking.
The study  found that autistic children yawned much more when they were watching the video intently, indicating the likelihood that they miss visual cues in everyday life. It has previously been established that children with autism are much less likely to experience contagious or ‘social’ yawning. The researchers state that this difference is a result of the tendency of children with autism to avoid looking at the faces of others.
The announcement follows research from Durham and Northumbria Universities that explored the role of eye contact in conversation. In a presentation at the British Science Festival  in Newcastle, Debbie Riby explained that looking away from someone as you speak to them is an important part of human interaction. She also reported that children with autism miss important visual clues when listening.
She said: "One of the really important things for teachers to be aware of is that we shouldn't expect children to keep looking at us, when they're trying to think. And that goes for a teacher of a typically developing child, a child with autism or a child with Williams syndrome.
"If teachers work with pupils with autism, they also need to be aware that these children might be missing important non-verbal cues. We could encourage them to look at us when they're listening, but we shouldn't get that mixed up with when they're thinking."
IPCC report calls for “substantial and sustained” reduction in carbon emissions
The latest report from the Intergovernmental Panel on Climate Change  calls for significant reductions in carbon dioxide emissions, reports The Guardian . The international organisation of representatives from the governments of over 120 countries publishes regular reports predicting the future of the climate based on current research.
The report makes predictions about several aspects of climate change and the issues that surround it. Scientists predict that by the middle of this century, global temperature will rise 1.4-2.6C if carbon emissions continue to rise at the same rate as today. This could be reduced to 0.4-1.6C if all emissions were halted immediately, and a large amount of carbon dioxide was captured from the atmosphere.
According to the report, half a trillion tonnes of carbon from coal, oil and gas have been burned since the beginning of the Industrial Revolution, and the huge acceleration in consumption means that we will burn through another half a trillion in the next few decades.
Sea levels are predicted to rise 45-82cm between now and 2100 if nothing is done to curb emissions, with a lower level of 26-55cm if emissions were halted. Melting ice sheets will drive up the sea level, along with the expansion of liquid water caused by higher temperatures. Scientists say there is a 66% chance that the Arctic will be entirely ice-free before 2050, and between 35-85% of global glacier volume will have melted by 2100.
Droughts have become more frequent and more extreme in the Mediterranean and in western Africa. Researchers are also 90% certain that warmer days and nights have increased significantly and heatwaves are more frequent and longer in Europe, Asia and Australia.
Curiosity rover discovers a high concentration of water in Martian soil
The Curiosity rover has discovered that water exists in soil on Mars in quantities that could make long-term habitation viable, according to a new study.
In each cubic foot of Martian soil, there is around a litre of water. This means that, with the right equipment, settlers could extract a day’s water needs from soil that could fit in a large cardboard box.
The research from Rensselaer Polytechnic Institute indicated that the soil is around 2% water by weight, a level that could almost support some types of cactus, if the water were liquid. In reality, the surface of Mars is usually far below freezing, so any water is found in tiny frozen fragments.
"For me, that was a big 'wow' moment," lead author Laurie Leshin told SPACE.com . "I was really happy when we saw that there's easily accessible water here in the dirt beneath your feet. And it's probably true anywhere you go on Mars."
The research is one of five papers published in Science in the last week that reports what Curiosity has been exploring in its first 100 days on Mars. Researchers also found that the soil on Mars absorbs water from the atmosphere, and that it contains a chemical called perchlorate.
Perchlorate is not something you’d want to drink. "Perchlorate is not good for people. We have to figure out, if humans are going to come into contact with the soil, how to deal with that," said Leshin.
"That's the reason we send robotic explorers before we send humans — to try to really understand both the opportunities and the good stuff, and the challenges we need to work through," she added.
Curiosity has also discovered that water is likely to exist across most of the planet’s surface, since the top soil layers appear almost uniform. It also found a type of volcanic rock that surprised researchers.
"Of all the Martian rocks, this one is the most Earth-like. It's kind of amazing," said Curiosity lead scientist John Grotzinger, a geologist at the California Institute of Technology in Pasadena. "What it indicates is that the planet is more evolved than we thought it was, more differentiated."
New form of matter discovered that behaves a bit like a lightsaber
Ever wanted a real lightsaber? We might be one step closer, with the discovery of a form of matter that behaves like the futuristic sword.
Light usually travels in photons, which don’t have mass and don’t interact, but these new photonic molecules deflect and push against one another, reports The Huffington Post .
"What we have done is create a special type of medium in which photons interact with each other so strongly that they begin to act as though they have mass, and they bind together to form molecules," Lukin said in the statement. "This type of photonic bound state has been discussed theoretically for quite a while, but until now it hadn't been observed."