China has pulled off two-way laser communication between Earth and the moon, making it only the second nation after the United States to do so. But the data rates it achieved were well behind those recorded by Nasa more than a decade ago, and that has left space experts scratching their heads. Using telescopes in Yunnan province and an experimental satellite that is now orbiting the moon after a launch mishap in 2024, the team recorded a downlink speed of 100 megabits per second and an uplink...