QUICK TAKES

HITTING THE BRAKES Earth’s solid inner core may be slowing its rotation so much that it could now be spinning slower than the mantle, an analysis of seismic data shows. This differential rotation between layers may be linked to changes in the planet’s magnetic field and length of day.

ALEXA, FIND ALIENS Astronomers have enlisted a deep-learning algorithm to comb radio data from the Breakthrough Listen project for signs of extraterrestrial intelligence. The AI turned up over 20,000 possible signals; researchers found eight to be “promising” and worthy of follow-up observations.

COSMOLOGICAL COUPLING Measurements of black hole growth in elliptical galaxies could support a theory that black holes are the source of dark energy, the mysterious pressure driving the expansion of the universe. The theory suggests black holes are not singularities but instead enclose vacuum energy, the amount of which grows as the universe expands.

ROVER LIMITATIONS Researchers are questioning the ability of Mars rovers to detect traces of past life. Testing shows current and next-gen rover instruments are barely able to detect fossilized microorganisms in analogous desert environments on Earth, where we know such life flourishes.

CLIMATE MOONSHOT Astronomers have calculated that it would be possible to halt climate change by firing dust from the Moon to the L1 Lagrange point to block sunlight from reaching Earth. In a statement, the team said they are not experts in climate change, just exploring options. —