On 4 March 2024, the MeerKAT radio telescope in South Africa recorded a radio pulse a few milliseconds long. The signal, catalogued as FRB 20240304B, had been travelling for roughly ten billion years: it was emitted when the universe was about three billion years old. It is the most distant fast radio burst yet identified, as Becky Ferreira reports for 404 Media, and its host galaxy sits at redshift 2.148 ± 0.0013, according to the paper in Science led by Manisha Caleb of the Sydney Institute for Astronomy — more than twice as distant as the next-farthest FRB on record, a burst found in 2023. The burst arrived in 2024; the localization, follow-up and analysis took more than two years to publish.
Redshift, written z, is the stretching of a signal’s wavelengths as they cross expanding space: higher z means a longer journey and an earlier emission. A z of 2.148 means every wavelength from FRB 20240304B arrived stretched by a factor of about 3.1. The sample context is what makes the record more than a trivia entry. Fast radio bursts are millisecond transients with no settled explanation, and only about one hundred of them have identified host galaxies with measured redshifts. The distribution of those hundred is not a fair sample of the universe, as Caleb’s team notes:
Only a small number of FRB host galaxies have been identified at z ≳ 1. This observational bias is driven by the sensitivity limit of radio observations that are capable of detecting FRBs and localizing their coordinates.
In other words, the known FRB population says as much about telescope sensitivity as about where bursts actually occur. The detection chain here shows what beating that limit takes. MeerKAT localized the burst precisely in the radio, but, per NASA’s account of the follow-up, the world’s largest ground-based telescopes could see nothing at that position. The James Webb Space Telescope, observing in the near-infrared, resolved what it described as a “low-mass, clumpy, starforming galaxy” hosting the burst. Ground-based optical astronomy had run out of photons; the host only existed on the sky for JWST.
A magnetar candidate, not a magnetar
What made the burst is unknown, as it is for FRBs generally — some repeat, some are one-offs, which suggests more than one progenitor class. For this one, the team speculates a magnetar, the intensely magnetized remnant of a massive star that ended in a supernova. The evidence is consistency, not identification: “The low stellar mass, active star formation, and low metallicity of the host galaxy are consistent with a magnetar origin of the FRB,” the researchers write. A young, chemically primitive, star-forming dwarf is the kind of environment where massive stars live fast and die young, so the host fits the theory. Nothing observed rules the alternatives out.
The payoff for finding bursts this far back is what the signal picks up en route. An FRB’s frequency spread and polarization are altered by the plasma and magnetic fields along its entire line of sight, so a pulse from z = 2.148 has effectively sampled ten billion years of intervening matter. One burst gives one line integral through the cosmos; a population of high-redshift bursts would let cosmologists compare the intergalactic medium then and now. That is the projected use, not a measured result — it requires exactly the sample this discovery argues is now within reach.
Quantum spin shoves a 100-mg diamond
Three other papers in the week’s stack run from the largest scale to the smallest and back. In Science Advances, a team led by Anshuman Nayak at the Okinawa Institute of Science and Technology moved a centimetre-scale diamond weighing 100 milligrams using quantum spin — described as by far the largest object ever manipulated by a quantum effect, and the first massive enough that gravity cannot be neglected in the experiment. A hundred milligrams of diamond is roughly 5 × 10²¹ carbon atoms (0.1 g at 12 g per mole), driven by forces originating in electron spins — angular momentum at the single-particle scale — inside the crystal’s nitrogen-vacancy (NV) centres.
The mechanism: a green laser polarises the NV electrons into a chosen spin state, which shifts the slab’s magnetic moment; that moment couples to a magnetic-field gradient and produces a net mechanical force on a diamagnetically levitated oscillator. Extending such a force beyond atomic scales had resisted experiment, the team wrote: “We have demonstrated the motional driving of a massive diamagnetically levitated mechanical oscillator by the force of NV spins in a gradient magnetic field.” A levitated diamond that moves when you flip its electrons’ spins is a benchtop bridge between quantum and everyday mechanics — the claim here is a demonstration, not yet a device.
Yak X, a bovine that kept to itself
In Current Biology, researchers co-led by Jonas Oppenheimer and Alexandre Gillardet of Stockholm University report sequencing ancient genomes from bones in Siberia’s Denisova Cave and identifying a previously unknown bovine, informally named yak X. The lineage began diverging from living yaks about 400,000 years ago and was genetically its own population by 250,000 years ago. The youngest bones date to roughly 27,200 years ago, so extinction came sometime after that, in the late Pleistocene. Domestic cattle dominate the bovine family today; aurochs, steppe bison and now this lineage record how much of that family is gone.
The striking finding is what the genomes do not show. “Yak X is a Pleistocene megafaunal species previously unknown to genomics,” the team writes, and it “appears to have become genetically isolated from other bovines including bison and aurochs despite their apparent geographic proximity.” They contrast this directly with the cave’s other inhabitants: “This lack of gene flow is in notable contrast to hominins at Denisova Cave, which displayed complex patterns of admixture among multiple divergent lineages.” Neanderthals and Denisovans interbred at this address; the local yak, surrounded by relatives, did not.
A planet born from stellar ash — and being eaten
In Nature Geoscience, a team led by Jamie Williams at the University of Warwick reports what it calls the first direct evidence of a second-generation planet: a world formed after its star died. HS 0209+0832, a white dwarf about 270 light years from Earth, was once Sun-like; some five million years ago it shed its red-giant shell and collapsed. Out of that ejected material, the researchers infer, a new planet coalesced — and is now falling back in. The white dwarf’s spectrum shows zinc, copper and niobium, elements they associate with second-generation material, distinct from the silicon and iron of first-generation planets like Earth. The material being accreted is “unlike any Solar System object,” the team writes — spectral inference, not a picture of the planet, so “candidate” is the honest word.
Each of these four results is one datum: one burst at high redshift, one levitated slab, one extinct genome, one polluted white dwarf. The numbers to watch are the sample sizes. For the FRB, the prediction to test is whether MeerKAT-class surveys and JWST follow-up turn z ≳ 1 from a rarity into a population. For the white dwarf, Williams’s team says what comes next: “Establishing a sizable sample of such systems will open a window on second-generation planet formation.”