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Asteroids headed for a collision with the Earth, if found early enough, can be acted upon to prevent the potentially devastating consequences of an impact. One technique to divert an asteroid, called kinetic impact, uses a spacecraft to crash into the body at high speeds.

This approach delivers the momentum of the spacecraft, while also providing an additional boost of momentum through the production of impact crater ejecta exceeding the asteroid’s escape velocity. Researchers at Lawrence Livermore National Laboratory (LLNL) have been studying the effectiveness of the kinetic-impactor strategy by carrying out 3D simulations of the process.

In a new paper published in Icarus(link is external), LLNL planetary defense researchers find that asteroid deflection by kinetic impact is sensitive to a range of asteroid characteristics, including strength, porosity, rotation and shape. These and other asteroid properties may not be well constrained before an actual deflection mission is staged, leading to variability in the deflection outcome. By simulating a range of initial conditions for the target asteroids, researchers were able to quantify, for example, how greater target strength decreases the delivered momentum impulse and how, for an asteroid of constant size, added porosity can result in more effective deflections, despite the dampening of the shock waves produced during an impact

Improved agricultural water management could halve the global food gap by 2050 and buffer some of the harmful climate change effects on crop yields. For the first time, scientists investigated systematically the worldwide potential to produce more food with the same amount of water by optimizing rain use and irrigation. They found the potential has previously been underestimated. Investing in crop water management could substantially reduce hunger while at the same time making up for population growth. However, putting the findings into practice would require specific local solutions, which remains a challenge.

Natural disasters made 2015 a miserable year for many people around the world. According to the United Nations’ Office for Disaster Risk Reduction, the statistics were brutal. At least 98.6 million people were affected by natural disasters ranging from droughts to floods, and the economic damage could have been as high as $66.5 billion. Using the data available from the Belgian non-profit Center for Research on the Epidemiology of Disasters (CRED), the UN reports that almost 23,000 people died from the 346 natural disasters reported across the world.

A new study has shown that both organic milk and meat contain around 50% more beneficial omega-3 fatty acids than conventionally produced products. Analysing data from around the world, the team led by Newcastle University, reviewed 196 papers on milk and 67 papers on meat and found clear differences between organic and conventional milk and meat, especially in terms of fatty acid composition, and the concentrations of certain essential minerals and antioxidants.

Bicycle ownership around the world is declining amid rising wealth levels and increased use of motorised vehicles in developing countries, a study has found.

Four out of ten households on the planet own a bike, according to a paper based on surveys from 150 countries between 1989 and 2012. But the growing popularity and affordability of motorised transport, such as cars and scooters, “have disfavoured bicycle use”, the researchers say.

China in particular experienced a collapse in bike ownership rates since 1992, when 97 per cent of households had bikes. However, this dropped to 63 per cent by 2009, the study shows, with ownership rates in most other countries either flat or decreasing.

In Togo, bike ownership has remained stable at around 34 per cent of households between 1998 and 2010, but in Paraguay ownership rates dropped from 57 per cent of households in 1996 to 39 per cent in 2002, the paper states.

These trends could be expected as the number of motor vehicles per person has increased over the past decade at a rate “never seen before in human history”, in particular in China, India and parts of Africa, says Marc Shotten, a transport specialist at the World Bank’s Global Road Safety Facility in the United States.