In the vast expanse of the universe, where unimaginable forces and celestial bodies coexist, astrophysicists have discovered a mesmerizing phenomenon. After a star is torn apart by a supermassive black hole, radio waves continue to burst forth from the ensuing wreckage for hundreds of days. This revelation challenges our previous understanding and raises intriguing questions about the behavior of these cosmic giants.
With the help of three powerful radio telescopes – the Very Large Array in the United States, MeerKAT in South Africa, and the Australian Telescope Compact Array – an international team of astrophysicists conducted a groundbreaking study. They meticulously collected long-term data on 24 black holes, all of which had consumed stars.
To their astonishment, the researchers observed that ten of these black holes emitted a sudden burst of radio waves between 500 to 2,000 days after their stellar feast. This timeframe far exceeded their expectations, as existing theories suggested the radio waves would dissipate within weeks or months.
The implications of this discovery are profound. Astrophysicist and lead author Yvette Cendes remarks that “up to half of all black holes that shred a star ‘burp’ material years after the initial event.” This unexpected revelation has been dubbed a case of “cosmic indigestion.” The team is still grappling to comprehend the underlying reasons behind this peculiar behavior.
When a star ventures too close to a black hole, it experiences an extreme gravitational pull, causing it to morph into the shape of spaghetti. The resulting tidal disruption event is accompanied by a blinding optical flare, one of the brightest phenomena in the universe.
The initial stages of these events typically generate radio waves in 20 to 30 percent of cases. However, the scientific community has historically focused on capturing the early stages of these events and swiftly moved on to other research endeavors. As Cendes candidly remarks, “radio telescope time is precious,” and the impulse to examine the aftermath of past explosions has been minimal.
In recent years, a paradigm shift has begun to occur. Last year, Cendes and her team stumbled upon a black hole twenty million times more massive than the Sun emitting jets of radio waves nearly three years after devouring a star. This unexpected discovery, affectionately nicknamed Jetty McJetface, prompted the researchers to question what the other 23 black holes they were studying might be doing.
This discovery defied popular belief that black holes function as cosmic vacuum cleaners sucking stars into oblivion. Instead, they create a messy scene where only a fraction of the star’s matter actually passes the event horizon. Roughly half of the stellar material gets expelled into the surrounding galaxy, while the remainder forms an accretion disk that orbits the black hole.
The team of astrophysicists presents two potential explanations for the late emission of radio waves. One theory suggests that it takes a significant amount of time for the debris revolving around the black hole to settle into a stable orbit. This settling period could contribute to the delayed radio wave emissions.
Another possibility focuses on the weakly bound debris forming a spherical envelope around the supermassive black hole. The authors propose that this envelope must cool and contract extensively to generate an accretion disk, which could account for the late-onset radio waves observed in the study. The accretion process could potentially supply the energy needed for the envelope to contract fully.
The discovery of late-onset radio waves from star-swallowing black holes challenges our understanding of these enigmatic cosmic entities. It compels us to broaden our research focus and explore the aftermath of stellar collisions with greater depth and curiosity. While many questions remain unanswered, this remarkable finding shines a light on the astonishing complexity of our universe and the ceaseless wonders it has yet to reveal.