Physics Today Daily Edition
BBC: The European Space Agency has released the first full-sky maps from its Gaia space telescope. Launched in 2013, Gaia is a follow-up to the Hipparcos satellite, which in the 1980s and 1990s cataloged the position, brightness, distance, and proper motion of 100 000 stars. In just three years Gaia has created a catalog 20 times as large, with position and brightness measurements for more than 1 billion stars in the Milky Way. The database also includes distance and proper motion for 2 million stars. By the end of its five-year mission, Gaia is expected to have collected a full set of measurements for nearly all the stars in the database. Beyond the four characteristics measured by Hipparcos, Gaia will also be measuring stars' radial velocity—the motion of the stars toward or away from Earth as they sweep through the galaxy. The additional measurements will provide information about the structure and internal dynamics of the Milky Way, which should allow researchers to more accurately model the evolution of the galaxy.
Atlantic: Although it is well known that the Moon is responsible for Earth’s tides, researchers say it might also affect earthquakes. Based on two decades' worth of data, Satoshi Ide of the University of Tokyo and colleagues have determined that some of the largest earthquakes have occurred when Earth’s crust was under the highest tidal stress. Those include the earthquakes that struck Sumatra on 26 December 2004; Maule, Chile, on 27 February 2010; and Tohoku-Oki, Japan, on 11 March 2011. The reason may be that the tugging of the Moon on Earth’s crust, although relatively weak, causes tiny faults to grow into a giant rupture. If so, future earthquake prediction methods may need to take into account the Moon’s pull, especially in earthquake-prone areas.
USA Today: The CEO of United Airlines, Oscar Munoz, said in a radio interview that because "Farmers' Almanac is calling for a very nasty winter, particularly in Chicago ... our operating team is hard at work as to how are we going to accommodate passengers." Company spokesperson Charles Hobart said that United did not actually consult Farmers' Almanac and that Munoz was quoted out of context, but that has not stopped the company from receiving significant criticism. Several meteorologists have pointed out that the almanac does not have a good track record for its seasonal weather predictions; others compared consulting the almanac with consulting an astrologer. Hobart says the company actually has several aviation meteorologists on staff.
Science: Cosmologists have long held that the universe is isotropic—fundamentally the same in all directions. A new study of the cosmic microwave background (CMB) radiation as mapped by the Planck spacecraft supports that assumption in the most stringent test yet. Daniela Saadeh and Andrew Pontzen of University College London and their colleagues used a supercomputer to look for CMB temperature and polarization patterns that would indicate a special direction in space. Based on their findings, the researchers estimate there is only a 1 in 121 000 chance that the universe is anisotropic. Their work increases the confidence in isotropism by an order of magnitude over previous analyses.