Today in Science: Polarized light reveals black hole mystery

Science, analysis, illumination March 28, 2024: Polarization of light around our galaxy's black hole, hummingbird flight modes, and pop songs are becoming simpler and catchier.  —Andrea Gawrylewski, Chief Newsletter Editor TOP STORIES Polarized Light in the Galaxy's Heart The polarized view of the Milky Way black hole. The lines mark the orientation of polarization, which is related to the magnetic field around the shadow of the black hole. Credit: EHT Collaboration A new image captured by the Event Horizon Telescope (EHT) shows polarized waves of light swirling around the supermassive blackhole at the heart of the Milky Way. The magnetic fields generated by plasma whipping around Sagittarius A* (Sgr A* for short) polarize light waves at a 90-degree angle to themselves. The EHT combines radio observatories on multiple continents to form a virtual Earth-size telescope, an instrument with the highest resolution in all of astronomy. Why this matters: Astronomers have seen polarization around another supermassive blackhole, M87*, which is much more massive than Sgr A*. Polarization around Sgr A* suggests that strong and well-organized magnetic fields could be common to all black holes. Also, because M87*'s magnetic fields drive powerful outflows or "jets," the results hint that Sgr A* could have a hidden and faint jet all of its own. What the experts say: "This new image, along with a strikingly similar polarization structure seen in the much larger and more powerful M87* black hole, shows that strong and ordered magnetic fields are critical to how black holes interact with the gas and matter around them," says Sara Issaoun, research co-leader and NASA Hubble Fellowship Program Einstein Fellow at the Center for Astrophysics at Harvard & Smithsonian. Hummingbird Flight Hummingbirds have an internal speedometer that they use during forward flight. An experiment tracked 3,500 hummingbird flights inside a 12-foot-long tunnel with a perch at one end and a feeder at the other. The researchers projected vertical stripes on the walls of the tunnels, either closer together or farther apart, anticipating that this would affect how the birds perceived the motion of their surroundings while in flight. But when they were flying forward, the hummingbirds did not alter their speed at all in response to the vertical stripes on the wall. The birds' up and down movement WAS dependent on what they saw on the walls.  Why this is interesting: Hummingbirds seem to be able to switch between some internal speed clock and a flight mode that incorporates external signals. Indeed, hummingbird brains have evolved to make rapid transitions from visual signals to motor outputs.  Potential applications: Whatever internal mechanism the birds use to predict how their movement will affect the flow of scenery around them could help engineers improve drone technology, says Bo Cheng, a mechanical engineer at Pennsylvania State University. "Can we develop a mathematical model for this prediction of optical flow?" Cheng asks. If so, "that could be very useful for drones." TODAY'S NEWS • Fruit fly researchers created a virtual AI fly using Google DeepMind, and trained it on hours of video footage of the real insects. | 5 min read • Lyrics to popular songs in the past 50 years have become simpler and more repetitive, according to a new study of hundreds of thousands of songs. | 4 min read • Scientists have begun analyzing the samples brought back from the asteroid Bennu by NASA's OSIRIS-REx mission. So far the results are surprising. | 10 min read Sourced from a 121.6-gram sample returned to Earth by NASA's OSIRIS-REx spacecraft, a small speck of material from the asteroid Bennu sits on a prepared microscope slide in an exhibition at the Smithsonian's National Museum of Natural History in Washington, D.C. Credit: NASA/Keegan Barber More News EXPERT PERSPECTIVES • In vitro fertilization is an exciting and quickly evolving field of scientific innovation that overcomes the biologic inefficiencies of natural conception, helps to treat disease and preserve fertility in people. The Alabama Supreme Court's ruling last month that embryos used in IVF are considered people will have immediate and long-term implications for patients and scientific innovation, writes H. Irene Su, a professor at University of California, San Diego, School of Medicine. "In the long term, this ruling compounds the myriad of U.S. policies that impede scientific progress in reproductive biology and women's health," she says. | 5 min read More Opinion Most of us learned about black holes in grade school, that their gravity is so intense that it pulls in any matter or light in its vicinity. And yet the most direct evidence that they actually exist only first arrived in 2015 with the detection of gravitational waves from the collision of two black holes. In fact, we only got visual proof that they were real in 2019! I'm not sure this all says more about the brilliance of Albert Einstein (who theorized their existence more than 100 years ago), or the captivating power of what a black hole represents. Either way, they're real and they're spectacular.  Email me anytime with ideas and feedback: newsletters@sciam.com. Until tomorrow! —Andrea Gawrylewski, Chief Newsletter Editor Subscribe to this and all of our newsletters here. 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