Jess Speedie, a PhD candidate at the University of Victoria (UVic), has helped solve one of the universe's many mysteries. 

Most physicists and astronomers have believed that planets form via core-accretion, whereby particles in a star's protoplanetary disk 香蕉视频直播� a rotating, Frisbee-shaped cloud of gas and dust 香蕉视频直播� stick together over millions of years. 

香蕉视频直播淭he stuff that the planets form out of is basically the leftovers of the star香蕉视频直播檚 formation," said Speedie. "You have many small particles and they ... conglomerate into larger and larger objects until, eventually, you get a planet.香蕉视频直播�  

For decades, however, others have theorized that planets can form in another way, as result of gravitational instability in a star香蕉视频直播檚 disk. In these cases, some physicists and astronomers argued that the gaseous Frisbees can be so massive and dense that matter can drift away from stars, resulting in the formation of spiral arms. 

"In the spiral arms, that's where you have regions of higher density, and those spiral arms basically fragment into clumps, and those clumps go on to further collapse into giant planets," said Speedie, who added that these planets can form in just thousands of years, as opposed to millions. 

However, there has been no proof to support this theory 香蕉视频直播� until now. 

In 2020, Dr. Cassandra Hall, an assistant professor of computational astrophysics at the University of Georgia, predicted that the disks surrounding gravitationally unstable stars emit detectable radio-wave signatures.  

香蕉视频直播淪he discovered the equivalent of a COVID test, but to tell whether or not a disc is gravitationally unstable,香蕉视频直播� said Speedie. 

To put her prediction to the test, in 2022, Hall and a team of 10, which included Speedie and Ruobing Dong, an assistant professor of astronomy and physics at UVic, secured time on the Atacama Large Millimeter Array (ALMA), a telescope located in a high-elevation desert in northern Chile.  

ALMA香蕉视频直播檚 operators soon aimed the 66-antenna machine at AB Origae 香蕉视频直播� a star 529 light years away from Earth. Not long before, physicists and astronomers discovered planets circling the distant A-type star whose formation couldn香蕉视频直播檛 be explained by core accretion 香蕉视频直播� an indicator that the star香蕉视频直播檚 disk is gravitationally unstable. 

For two years, Speedie poured over the radio waves ALMA collected in search of gravitational instability signatures. Then, two years later, in 2024, Speedie found what she was looking for, proving Hall香蕉视频直播檚 test accurate. This confirmed that the planets in AB Origae香蕉视频直播檚 disk formed via gravitational instability 香蕉视频直播� a discovery of huge significance.

"To understand the planet-formation process will help us understand how we get this diversity of planets around other stars," said Speedie, who added that the next step for future research is to observe other young stars and build statistics about how often planets form via gravitational instability.

The finding could also shed light on other mysteries, including those closer to home.

香蕉视频直播淸Planets are] where the life could be,香蕉视频直播� she said. 香蕉视频直播淭hat's where you could have consciousness. It's not going to happen on the surface of stars, it's not going to happen on the surface of black holes. Planets are where the stories happen.香蕉视频直播� 

"How did Earth form? How did Jupiter form? Is our solar system unique in this diversity of planets in the Milky Way?香蕉视频直播� Speedie added. 香蕉视频直播淲e want to know our own origin stories. We want to know how we got here."