The discovery of a star that survived an encounter with a supermassive black hole and came back for more has left astronomers stunned. For decades, scientists have observed spectacular flares caused by stars falling onto these cosmic monsters, only to be destroyed in the process. However, a team of researchers from Tel Aviv University has made a groundbreaking finding: one such flare, named AT 2022dbl, was repeated nearly two years after its initial occurrence, suggesting that at least part of the star survived.

Led by Dr. Lydia Makrygianni and Prof. Iair Arcavi, the study published in the Astrophysical Journal Letters reveals that this flare might not have been a full stellar disruption as previously thought. Instead, it could be a result of the partial destruction of the star, with much of its material surviving to come back for a second, nearly identical passage.

The implications of this finding are significant. If future flares from the same location occur at regular intervals, it would suggest that these events might not be one-off occurrences but rather part of a more complex and dynamic process. “This discovery upends conventional wisdom about such tidal disruption events,” says Prof. Arcavi. “We’ll have to re-write our interpretation of these flares and what they can teach us about the monsters lying in the centers of galaxies.”

The study’s findings also challenge long-held assumptions about black holes, which are notoriously difficult to study due to their complete darkness. By observing the aftermath of a star’s encounter with a supermassive black hole, scientists have gained valuable insights into these enigmatic objects.

As researchers continue to investigate this phenomenon, they may uncover even more secrets about the complex interactions between stars and supermassive black holes. The question now is: will we see a third flare after two more years, in early 2026?

The mysteries of black holes have long been shrouded in an aura of mystery. These cosmic monsters are capable of warping space and time around them, creating regions from which nothing – not even light – can escape. However, recent research has revealed that these enigmatic entities also possess a hidden harmony, a “singing” quality that scientists are only now beginning to understand.

Quasinormal modes, as they’re called, are the ripples in space-time produced by disturbances around black holes. These vibrations can be strong enough to detect from Earth, offering a unique opportunity to measure a black hole’s mass and shape. However, calculating these vibrations through theoretical methods has proven a major challenge, particularly for those that rapidly weaken.

A team of researchers at Kyoto University has developed a new method for calculating the vibrations of black holes using the exact Wentzel-Kramers-Brillouin (WKB) analysis. This mathematical technique involves extending space near the black hole into the complex number domain, revealing a rich structure of the black hole’s geometry.

The research team found that this approach allowed them to follow wave patterns in great detail, even in regions difficult to analyze with other existing methods. They incorporated complex features such as Stokes curves, which designate where the nature of a wave suddenly changes, into their analysis. The findings revealed that the team had succeeded in developing a method that systematically and precisely captures the frequency structure of rapidly weakening vibrations.

This breakthrough makes it possible to analyze the “ringing sounds” of black holes across a wide range of theoretical models. Ultimately, this may help improve the precision of future gravitational wave observations and lead to a deeper understanding of the true nature of our Universe and its geometry. The research team plans to extend their approach to rotating black holes and explore the application of exact WKB analysis in studies related to quantum gravity effects.

Cosmic particles known as neutrinos have long been shrouded in mystery, their properties and behavior still not fully understood by scientists. These ghostly entities, which come in three “flavors” – electron, muon, and tau – can be lethal to massive stars more than 10 times the size of our sun. Neutrinos are notorious for being slippery, making it nearly impossible to collide them with each other in a lab setting.

Recently, researchers from the Network for Neutrinos, Nuclear Astrophysics, and Symmetries (N3AS) have made a groundbreaking discovery through theoretical calculations. They found that massive stars can act as “neutrino colliders,” where neutrinos steal thermal energy from these stars, causing their electrons to move at nearly the speed of light. This drives the star to instability and collapse.

As the collapsing star’s density becomes incredibly high, its neutrinos become trapped, leading to a series of collisions among themselves. With purely standard model interactions, the neutrinos will predominantly be electron flavor, resulting in a relatively “cold” matter core that might leave behind a neutron star remnant.

However, if secret interactions are at play, changing the flavor of neutrinos radically, the outcome is drastically different. In this scenario, neutrinos of all flavors collide, producing a mostly neutron “hot” core that may eventually give rise to a black hole remnant.

Future experiments like the Deep Underground Neutrino Experiment (DUNE) at Fermi National Accelerator Lab might be able to test these ideas, and observations of neutrinos or gravitational waves from collapsing stars could provide further insights into this phenomenon. The research, led by UC San Diego researchers and published in Physical Review Letters, has been funded by institutions such as the National Science Foundation and the Department of Energy, underscoring the importance of continued study in this area.