When our universe was less than half as old as it is today, a burst of energy that could cook a sun’s worth of popcorn shot out from somewhere amid a compact group of galaxies. Some 8 billion years later, radio waves from that burst reached Earth and were captured by a sophisticated low-frequency radio telescope in the Australian outback. 

The signal, which arrived in June 2022, and lasted for under half a millisecond, is one of a growing class of mysterious radio signals called fast radio bursts. In the last 10 years, astronomers have picked up nearly 5,000 of them. This one was particularly special: nearly double the age of anything previously observed, and three and a half times more energetic. 

No one knows what causes fast radio bursts. They flash in a seemingly random and unpredictable pattern from all over the sky. But despite the mystery, these radio waves are starting to prove extraordinarily useful. Read the full story.

—Anna Kramer

The depressing truth about TikTok’s impending ban

Trump’s 2020 executive order banning TikTok came to nothing in the end. Yet the idea—that the US government should ban TikTok in some way—never went away. It would repeatedly be suggested in different forms and shapes. And eventually, on April 24, 2024, things came full circle with the bill passed in Congress and signed into law.

A lot has changed in those four years. Back then, TikTok was a rising sensation that many people didn’t understand; now, it’s one of the biggest social media platforms. But if the TikTok saga tells us anything, it’s that the US is increasingly inhospitable for Chinese companies. Read the full story.

—Zeyi Yang