What is the blood-brain barrier?

A pride of lions silently patrolling the grassland at dusk; a cheetah closing in on its prey with mind-blowing speed; a watchful leopard curled artfully in a tree. There’s nothing quite like a big cat

THE MOST DOMINANT FORCE IN THE UNIVERSE IS ALSO ITS MOST MYSTERIOUS AND MOST UNANTICIPATED

Inside an unassuming building, behind a damp car park in Antwerp, Belgium, scientists are teaching two spacecraft to be dance partners for a performance that will take place in front of the Sun. It’s

The land Down Under seems ready-made for soul-stirring adventures. Its 16,000 miles of coastline are one long playground, with vertiginous cliffs riddled with hiking trails and reefs ripe for diving. There’s ancient flora and unique wildlife hiding in the rainforests, and cities that offer every activity under the sun. So pick up your hiking boots, paddle or flippers and get outdoors

When to use this chart 1 December at 00:00 UT 15 December at 23:00 UT 31 December at 22:00 UT On other dates, stars will be in slightly different positions because of Earth’s orbital motion. Stars tha