A new study suggests Mercury may have shrunk about 30% more than scientists previously thought, losing as much as 14 miles in diameter as its interior cooled and contracted over billions of years. "That's significant for a planet barely 3,000 miles (4,900 kilometers) across," reports the Associated Press. From the report: Mercury's rough surface, continually reshaped by debris hurled from impact craters, may have hidden the true extent of the loss, according to the researchers whose findings appear in the journal Geophysical Research Letters. The news comes one week after a pair of European and Japanese spacecraft shed its cruising platform and advanced toward Mercury. Known as BepiColombo, the linked craft are expected to enter orbit around Mercury in November before splitting up for a fuller survey. BepiColombo's laser instrument should confirm how much Mercury is withering as a result of internal cooling, said Gaku Nishiyama, the study's lead author who is taking part in the space mission. The shrinkage could be even more than his team is estimating based on measurements from NASA's Messenger spacecraft in the 2010s. Only one other spacecraft has ever visited Mercury, NASA's Mariner 10 in the 1970s.

Read more of this story at Slashdot.

alternative_right shares a report from ScienceDaily: A new analysis of more than 1,700 supernovae is questioning whether the universe is really accelerating at all. After accounting for the ages of the stars that produce these explosions, researchers found signs that cosmic expansion may actually be slowing. They also argue that the apparent acceleration changes with direction, which would be difficult to explain with dark energy. Other cosmologists dispute the conclusion, setting up a major test for upcoming observatories. The analysis has been published in Monthly Notices of the Royal Astronomical Society. The conclusion is disputed, though. The report mentions a separate paper co-authored by Professor Maria Vincenzi, also at the University of Oxford, that "concludes that observations continue to support an accelerating universe."

Read more of this story at Slashdot.