Astronomers may have discovered a new type of thermonuclear explosion that only occurs in neutron stars every 1,000 years. They call it a hyperburst.
An April launch is no longer possible for Artemis 1, which will send an uncrewed Orion capsule around the moon using a huge Space Launch System megarocket.
The Russian invasion of Ukraine has led top Ukrainian scientists to withdraw from final approvals of a landmark climate report.
With one of the world's most precise atomic clocks, physicists have observed time dilation, confirming Einstein's theory of relativity.