Einsteins Twist: Princeton Astrophysicists Unravel the Mystery of Black Hole Jets and Galactic Lightsabers

Princeton researchers have found that the M87* black hole emits energy outwards, which contributes to the formation of massive jets. This discovery, rooted in Einstein’s theory of relativity, challenges the traditional view of black holes and may be tested using advanced telescopes. The study opens up new ways of understanding black hole dynamics, although it stops short of explaining the jets’ power source. Source: SciTechDaily.com

A group of astrophysicists at Princeton has now determined that the energy close to black hole M87* pushes outside, not inside, a long-standing debate within the field.

The one thing everyone knows about black holes is that everything nearby gets sucked into them.

tight-fitting everything, it’s done.

“Although black holes are defined as objects from which nothing can escape, one of the most surprising predictions of Einstein’s theory of relativity is that black holes can actually lose energy,” said astrophysicist Eliot Quataert, Charles A. Young Professor of Astronomy at Princeton on Astronomy. Class of 1897 Foundation. “They can spin, and just as a spinning top slows down over time and loses momentum as it spins, a spinning black hole can also lose momentum around it.”

Scientists have widely accepted this model since the 1970s. They know that magnetic fields probably extract energy from spinning black holes – they just don’t know how.

A team of Princeton astrophysicists has now determined that the energy near the event horizon of the black hole M87* is pushing outward, not inward. (M87 is the name of the galaxy, Messier 87, so the black hole at its center is designated M87*.) The researchers also developed a way to test the prediction that black holes lose rotational energy. , Quataert said, and to establish it. it’s that energy that produces “the amazingly powerful currents we see that we call jets.”


An animation showing how the magnetic field crossing the black hole’s event horizon twists as the black hole spins faster. A faster spinning black hole “spins” the magnetic field faster, causing the black hole to lose more energy to its surroundings. A team of Princeton astrophysicists observed the wind-up of magnetic field lines in images from the Event Horizon Telescope of linear polarization from a black hole. Credit: Video by George Wong, Institute for Advanced Study and University of Princeton

These jets of energy flow “like a million-light-year-long Jedi lightsabers,” said former Princeton postdoc Alexandru Lupsasca, and they can extend 10 times longer than Milky Way galaxy.

The results of their work were recently published in the Astrophysical Journal. Andrew Chael, an associate research scholar in astrophysics, is the paper’s first author. He and co-author George Wong are both members of the Event Horizon Telescope team and have played key roles in developing the models used to interpret black holes. Chael, Wong, Lupsasca and Quataert are all theorists affiliated with the Princeton Gravity Initiative.

The team gave Chael credit for the key insight at the core of the new paper: that the direction in which magnetic field lines move reveals the direction of energy flow. From that, “the rest kind of fell into place,” Quataert said.

Model of M87* Twisting Magnetic Fields

The black hole M87* (the asterisk refers to the black hole at the center of the galaxy M87) caught the world’s attention when it was first detected by the Event Horizon Telescope. Since then, Princeton astrophysicists have discovered that the rotating magnetic field around a black hole determines the tell-tale polarization spiral seen in black hole images. In particular, the direction of energy flow (from hole to field or vice versa) determines how the polarization twists. By measuring which way the polarization spirals, it can be determined whether the magnetic field is extracting spin energy from the hole or pumping spin energy into it. Credit: Model by Andrew Chael, George Wong, Alexandru Lupsasca and Eliot Quataert, Princeton Gravity Initiative

“If you took the Earth, turned it all into TNT and blew it up 1,000 times a second over millions and millions of years, that’s the amount of energy we’d get from M87,” Wong said. is an associate research scholar with the Princeton Gravity Initiative and a member of the Institute for Advanced Study.

Scientists have known for decades that as a black hole begins to spin, it will drag the fabric of spacetime around it. The magnetic field lines passing through the black hole drag, and that slows the rotation, leading to the release of energy.

“Our new, sharp prediction is that every time you look at an astrophysical black hole, if it has magnetic field lines attached to it, there’s a transfer of energy — really crazy amounts of energy transfer,” said Lupsasca, a former Princeton research associate who is now an assistant professor of physics and mathematics at Vanderbilt University, and won the 2024 New Horizons in Physics Prize from the Breakthrough Prize Foundation for in his research on black holes.

As the energy flow near the event horizon of M87* flows outward, the team says the energy flow could theoretically enter another black hole. They are confident in their link between the flow of energy and the direction of magnetic field lines, and their prediction that the flow of energy from a black hole will be tested with the launch of the still theoretical “next generation” Event Horizon Telescope.

For the past year and a half, black hole researchers around the world have been proposing specs for the future instrument, Wong said. “Papers like ours can play an important role in determining what we need. I think it’s an incredibly exciting time.”

The four researchers emphasize in their paper that they have not shown that the spinning black hole “actually accelerates the extragalactic jet,” although the evidence certainly leans in that direction. Although the energy levels shown in their model are consistent with what jets need, they cannot rule out the possibility that the jet could be powered by rotation. plasma except for black holes. “I think it’s very likely that the black hole is driving the jet, but we can’t prove it,” Lupsasca said. “Even so.”

Reference: “Black Hole Polarimetry I. A Signature of Electromagnetic Energy Extraction” by Andrew Chael, Alexandru Lupsasca, George N. Wong and Eliot Quataert, 14 November 2023, The Astrophysical Journal.
DOI: 10.3847/1538-4357/acf92d

The research was supported by the Princeton Gravity Initiative, the Taplin Fellowship, the National Science Foundation (grant 2307888) and a Simons Foundation Investigator award.


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Image Source : scitechdaily.com

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