Physics Today Daily Edition
Atlantic: An exoplanet is commonly found by the telltale dimming of the light of a star as the planet passes in front of it. Earth-sized planets orbiting bright, hot stars like the Sun are nearly impossible to detect, however, because they are so small they don't block much of the star's brightness. For that reason, Michaël Gillon of the University of Liège in Belgium decided to look for planets in orbit around the smallest, dimmest stars. Most theories of planetary formation suggest that such stars should not have enough material around them to form planets, but Gillon argued that the theories are based on very few observations. Using the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) located in Chile, Gillon and his colleagues have identified an ultracool red dwarf only 40 light-years away and orbited by three planets. Subsequent observations from TRAPPIST and other observatories have revealed that all three are Earth-sized and are located in the habitable zone—the region around a star where liquid water may exist. Because of the star's small size and dimness, its habitable zone is much closer to it than the Sun's habitable zone is to the Sun. The closest two planets orbit the star every 1.5 days and 2.4 days.
Ars Technica: Several past experiments have found that increasing people's knowledge of climate change doesn't necessarily raise their concern about the issue. However, a new paper argues that because those studies treated "knowledge about climate change" as a monolithic concept, they don't necessarily reflect reality. The researchers separated knowledge into three categories: physical knowledge, causes knowledge, and consequences knowledge. Physical knowledge includes understanding concepts such as how carbon dioxide is produced; causes knowledge includes comprehending the effect humans have had on climate change; and consequences knowledge includes grasping the predicted global and local effects of climate change. In a survey of 2495 people in six countries—the US, Canada, China, Germany, Switzerland, and the UK—participants were asked their level of concern about climate change; then they were given questions that tested the three categories of knowledge. Researchers found that although greater physical knowledge correlated with lower concern, greater causes knowledge correlated with greater concern. Greater consequences knowledge also correlated with greater concern, except in Canada and China. Although the new questionnaire has limitations, it provides groundwork for future surveys on the topic.
Sputnik International: Less than two months after the launch of the first part of ExoMars, the Russian space agency Roscosmos announced that the launch of the second component will be delayed by two years, until 2020. ExoMars is a joint mission of Roscosmos and the European Space Agency. The first part of the mission, which will reach Mars orbit in October, includes an orbiter and a lander for studying the Martian atmosphere. Part two includes a rover that will drill into the Martian surface to search for life and perform geochemistry research. According to the team running the rover mission, the decision to postpone the second launch was made because of problems with the contractors and delays in production of the mission's scientific equipment.
Science: Last year, the council of representatives for the member states supporting the ITER fusion energy project in southern France created an independent panel to review the project's revised budget and schedule. Since construction began in 2013, ITER has been plagued with cost overruns and delays. In its report presented on 27 April, the panel said that although the revised startup date of 2025 is reasonable, the additional €4.6 billion ($5.3 billion) that will be needed to complete the project is not. In response, the council has instructed the ITER management team to find a way to continue with construction without exceeding the financial constraints. Projected costs for ITER, which was originally scheduled to be completed this year, have reached roughly $20 billion. The ballooning costs and sliding completion dates have caused several of the member states to consider cutting their support.
Ars Technica: At nearly 1 zettabyte (1 billion terabytes) per gram, DNA has a significantly higher data storage density than conventional storage systems. And the molecule is extremely robust: Fragments that are thousands of years old have been sequenced. The successful encoding of binary data as DNA base pairs in 2010 opened up the potential for using the molecule for long-term data storage. Now Microsoft is purchasing 10 million strands of DNA from Twist Bioscience, a biotech startup that has developed a machine for producing custom strings of DNA. Twist has been producing DNA for biology research labs. Currently, the price is roughly $0.10 per base, but Twist hopes to reduce that cost to $0.02. Reading the data involves traditional genetic sequencing, which costs about $1000 per genome. In initial tests with Twist, Microsoft says it has succeeded in retrieving all the data that had been encoded in the DNA. The price of storage means that commercial use is still a ways off, but improvements in both creating and sequencing DNA molecules will likely lead to lower costs.