French astronaut Thomas Pesquet stepped out on his first spacewalk Friday to help upgrade the power system outside the International Space Station with new, refrigerator-sized lithium-ion batteries.

Accompanied by American astronaut Shane Kimbrough, the men switched on their spacesuits internal battery power to mark the official start of the spacewalk at 6:22 am (1122 GMT), more than a half hour earlier than scheduled.

Japanese scientists say that silicon is likely the mystery element in the Earth's inner core, claiming progress on solving one of the planet's deepest secrets.

The part of the human brain that is involved in face recognition keeps developing into adulthood, a pair of new studies found, surprising scientists who thought brain tissue growth stopped in early childhood.

A mysterious type of radio wave from deep space, discovered only a decade ago, has been traced to a precise source for the first time, astronomers said Wednesday.

India will launch a rocket carrying 103 satellites next month in a record single mission, a report said Wednesday, as its famously frugal space agency looks to zoom ahead in the commercial space race.

The European Space Agency on Wednesday released stunning images of baby stars taking shape inside the Milky Way's Orion nebula.

The eggs of nonavian dinosaurs took three to six months to hatch, a long incubation period that could help explain dinosaurs' mass extinction 65 million years ago, according to new research.

As if 2016 has not been long enough, the year's dying minute will last an extra second to make up for time lost to Earth's slowing rotation, timekeepers say.

Groundbreaking astrophysicist Vera Rubin, who confirmed that the bulk of the universe is made up of invisible dark matter, has died in Princeton, New Jersey aged 88.

"Vera Rubin was a national treasure as an accomplished astronomer and a wonderful role model for young scientists," said Matthew Scott, president of the Carnegie Institution for Science.

Cheetahs are "sprinting" to extinction due to habitat loss and other forms of human impact, according to a new study out this week which called for urgent action to save the world's fastest land animals.