Compelling evidence that the structure of matter surrounding supermassive black holes has changed over cosmic time has been uncovered by an international team of astronomers. If true, the research led by the National Observatory of Athens and published today in Monthly Notices of the Royal Astronomical Society would challenge a fundamental law which has existed for almost five decades. Quasars – first identified in the 1960s – are some of the brightest objects in the universe. They are powered by supermassive black holes as matter, pulled by strong gravity, spirals inwards, forming a rotating disc-like structure which eventually plunges into the black hole.

The cosmos has served up a gift for a group of scientists who have been searching for one of the most elusive phenomena in the night sky. Their study, presented today in Science Advances, reports on the very first observations of a swirling vortex in spacetime caused by a rapidly rotating black hole. The process, known as Lense-Thirring precession or frame-dragging, describes how black holes twist the spacetime that surrounds them, dragging nearby objects like stars and wobbling their orbits along the way.

A new study posits a scenario in which a supernova shockwave sent critical ingredients for the formation of Earth-like rocky planets during the creation of the solar system. The creation of the solar system’s rocky planets likely required an injection of short-lived radionuclides (SLRs), including aluminium-26 (²⁶Al), from a supernova. Preexisting models have not been able to explain how this explosion could have injected necessary levels of the ingredients without causing the destruction of the protosolar disk. The newly proposed “immersion” mechanism preserves the disk, indicating that the conditions that lead to terrestrial planets may be more widespread in the universe than previously thought. “At least 10%, possibly 50% of Sun-like stars are likely to host protoplanetary disks with SLR abundances similar to those of the protosolar disk,” Ryo Sawada and colleagues write. “Our results suggest that Earth-like, water-poor rocky planets may be more prevalent in the Galaxy than previously thought.” Prior simulations could not achieve the SLR level necessary for terrestrial planet evolution (levels established from past meteorite analyses) without obstructing the solar system’s genesis. Now, Sawada et al. describe how a supernova roughly 1 parsec away could have produced the requisite SLR abundance without imperiling the protosolar disk. Their immersion mechanism incorporates shockwave-driven injections of the SLRs manganese-53 and iron-60 into the protosolar disk, triggering cosmic-ray nonthermal nucleosynthesis of ²⁶Al and additional SLRs. The calculations indicate that solar-mass stars in star clusters have a high probability of encountering a supernova within a distance of a parsec. This means there may be far more systems with the needed SLR abundances for terrestrial planet development.

For 10 months, a SETI Institute–led team watched pulsar PSR J0332+5434 (also called B0329+54) to study how its radio signal "twinkles" as it passes through gas between the star and Earth. The team used the Allen Telescope Array (ATA) to take measurements between 900 and 1956 MHz and observed slow, significant changes in the twinkling pattern, or scintillation, over time.

Pulsars are spinning remnants of massive stars that emit flashes of radio waves, a type of light, in very precise and regular rhythms. Due to their high rotation speed and incredible density. Scientists can use sensitive radio telescopes to measure the exact times at which pulses arrive in the search for patterns that can indicate phenomena such as low-frequency gravitational waves. However, gas in interstellar space can scatter a pulsar’s radio waves—spreading them out and slightly delaying when each pulse is received. Understanding and correcting these tiny, changing delays, which can be as small as tens of nanoseconds (a nanosecond is one-billionth of a second), helps keep pulsar timing as precise as possible.

Just as starlight “twinkles” in Earth’s atmosphere, pulsar radio waves also “twinkle”, or scintillate, in space. As the signal travels through clouds of electrons between the pulsar and Earth, it creates bright and dim patches across radio frequencies. These patterns aren’t static; they evolve as the pulsar, the gas, and Earth move relative to each other. This twinkling delays the pulses, and the amount of scintillation matches the extent of the delay. By frequently monitoring a single bright, nearby pulsar, the team observed these patterns shift and translated them into tiny timing delays. These methods can then correct the delays that matter for the most precise pulsar experiments.