Betelgeuse dimming explained by dust

Astronomers say they have solved the mystery of why Betelgeuse, one of the sky’s brightest stars, started getting dimmer in 2019. By mid-February this year, Betelgeuse had lost more than two-thirds of its brilliance — a difference noticeable to the naked eye. Some people speculated that this was a sign that the star was approaching the end of its life, but researchers working with the Hubble telescope now say it was probably caused by hot material that the star ejected into space, which then cooled and turned into dust.

The asteroid Ceres seems to have liquid water

The dwarf planet Ceres seemingly has a salty ocean of water beneath its surface. The ocean is the source of mysterious bright areas spotted on the distant world’s surface. Images from NASA's Dawn spacecraft, which dipped to less than 35 kilometres above Ceres’s surface on its 2018 mission, reveal the areas are deposits of mostly sodium carbonate. These were formed as briny water percolated up to the surface and then evaporated.

Scientists crack mystery of the origin of Stonehenge's giant stones

Scientists have solved an enduring mystery about Stonehenge, determining the place of origin of many of the megaliths that make up the famed monument in Wiltshire, England, thanks to a core sample that had been kept in the United States for decades.

Geochemical testing indicates that 50 of Stonehenge's 52 pale-grey sandstone megaliths, known as sarsens, share a common origin about 25 kilometres away at a site called West Woods on the edge of Wiltshire's Marlborough Downs.