Back in 2004, archaeologists excavated two pits in northern China that looked a lot like home brewing operations. Constructed between 3400 and 2900 BC by the Yangshao culture, each pit contained the remnants of a stove and assorted funnels, pots and amphorae.

Now, Jiajing Wang of Stanford University and colleagues report that the pottery shards contain residue and other evidence of starches, chemicals and plant minerals from specific fermented grains. The ancient beer recipe included broom corn millet, barley, Job's tears and tubers - that probably gave the beer a sweet flavor, the team wrote in the Proceedings of the National Academy of Sciences.

The findings predate the earliest evidence of barley in China by around 1,000 years. Beer may have been consumed at social gatherings, and brewing, not agriculture, spurred the introduction of barley to China, sciencenews.org reported.

Our home planet is young at heart. According to new calculations, Earth's centre is more than two years younger than its surface.In Einstein's general theory of relativity, massive objects warp the fabric of spacetime, creating a gravitational pull and slowing time nearby. So a clock placed at Earth's centre will tick ever-so-slightly slower than a clock at its surface. Such time shifts are determined by the gravitational potential, a measure of the amount of work it would take to move an object from one place to another. Since climbing up from Earth's centre would be a struggle against gravity, clocks down deep would run slow relative to surface timepieces, a report in sciencenews.org said.Over the 4.5 billion years of Earth's history, the gradual shaving off of fractions of a second adds up to a core that's 2.5 years younger than the planet's crust, researchers estimate in the May European Journal of Physics. Theoretical physicist Richard Feynman had suggested in the 1960s that the core was younger, but only by a few days.The new calculation neglects geological processes, which have a larger impact on the planet's age. For example, Earth's core probably formed earlier than its crust. Instead, says study author Ulrik Uggerhøj of Aarhus University in Denmark, the calculation serves as an illustration of gravity's influence on time - very close to home.

Sea turtles do not have an easy start to life. After hatching, they have to break out of their shell, dig their way out from beneath the sand, then make a mad dash across the beach to the water where they may or may not find food and safety - hopefully without getting snapped up by a predator. All of this requires a bit of luck and a lot of energy. And the energy a hatchling expends on breaking out of the nest is energy that can't be used on surviving the rest of the journey.Now, a new study has quantified the amount of energy a baby sea turtle uses to dig itself to the surface. Having lots of siblings - and, thus, lots of help - can really be a time and energy saver, researchers have reported in the Journal of Experimental Biology. That also implies that the conservation technique of dividing clutches may instead make hatchlings worse off.Figuring out the energy expenditure of baby sea turtles took some trial and error, a report in sciencenews.org said. For the final experiment, the scientists buried clutches of eggs just about to hatch beneath 40 centimeters of beach sand in a chamber with opaque walls.