Scientists believe that young planetary systems experience extreme growing pains as protoplanets collide and fuse—the process thought to have produced the Earth and moon. But such smashups have been difficult to observe in other solar systems.
Now astronomers at MIT, the National University of Ireland Galway, Cambridge University, and elsewhere have discovered evidence of a giant impact around the 23-million-year-old star HD 172555, 95 light-years away. It appears that at least 200,000 years ago, a roughly Earth-size body and a smaller one collided at more than 22,000 miles per hour—a crash so powerful that part of the larger body’s atmosphere was blown away.
The researchers examined data taken by the Atacama Large Millimeter Array in Chile to analyze the dust around HD 172555 and found carbon monoxide circling in large amounts, surprisingly close to the star; a star’s light normally causes this gas to break down at such close range. Their conclusion was that it must be the remnant of an atmosphere-stripping collision. “The only plausible process that could produce carbon monoxide in this system in this context is a giant impact,” says the study’s lead author, Tajana Schneiderman, a graduate student in MIT’s Department of Earth, Atmospheric, and Planetary Sciences.
“This is the first time we’ve detected this phenomenon of a stripped protoplanetary atmosphere in a giant impact,” says Schneiderman. “Everyone is interested in observing a giant impact because we expect them to be common, but we don’t have evidence in a lot of systems for it. Now we have additional insight into these dynamics.”
Toronto wants to kill the smart city forever
The city wants to get right what Sidewalk Labs got so wrong.
Saudi Arabia plans to spend $1 billion a year discovering treatments to slow aging
The oil kingdom fears that its population is aging at an accelerated rate and hopes to test drugs to reverse the problem. First up might be the diabetes drug metformin.
Yann LeCun has a bold new vision for the future of AI
One of the godfathers of deep learning pulls together old ideas to sketch out a fresh path for AI, but raises as many questions as he answers.
The dark secret behind those cute AI-generated animal images
Google Brain has revealed its own image-making AI, called Imagen. But don't expect to see anything that isn't wholesome.
Get the latest updates from
MIT Technology Review
Discover special offers, top stories, upcoming events, and more.