Bedtime Astronomy

A baffling cosmic event, designated AT2025ulz, was detected by LIGO and Virgo and is now considered a candidate for a never-before-seen phenomenon: a superkilonova. This oddball event, which took place 1.3 billion light-years away, initially resembled a kilonova—an explosion caused by the merger of two dense neutron stars. Kilonovae are known to forge the heaviest elements, such as gold and uranium.However, after about three days, AT2025ulz started to look more like a supernova, brightening, turning blue, and showing hydrogen in its spectra. The gravitational-wave data indicated that at least one of the colliding objects was less massive than a typical neutron star.Astronomers hypothesize that this "superkilonova" was a kilonova spurred by a prior supernova blast. The leading theory suggests that a rapidly spinning, massive star went supernova, birthing two "forbidden" sub-solar mass neutron stars. These newborn stars may have then spiraled together and merged, creating a kilonova. This scenario would explain why the event displayed features of both a supernova and a kilonova, potentially obscuring the initial merger. This potential cosmic rarity challenges our understanding of stellar death and the formation of heavy elements.

This episode explores a new five-year astronomical survey of the Large and Small Magellanic Clouds using the 4MOST spectrograph on the VISTA Telescope.Led by the Leibniz Institute for Astrophysics Potsdam, the 1001MC project will collect high-resolution spectra from nearly 500,000 stars to reveal their motions, chemical composition, and history.We discuss how this data could answer long-standing questions about the formation and evolution of these dwarf galaxies, with full operations starting in 2026.

New James Webb Space Telescope observations reveal that a seemingly ordinary young galaxy, seen just 800 million years after the Big Bang, hides a rapidly growing, dust-enshrouded supermassive black hole.Infrared data from JWST’s MIRI instrument challenge established models of black hole and galaxy co-evolution and suggest that many similar objects may remain undetected across the universe.

Discover the fastest cosmic explosion ever recorded! We explore GRB 230307A, a gamma-ray burst detected by NASA's Fermi Space Telescope that reached 99.99998% of light speed—a breakthrough led by University of Alabama graduate researchers.Learn how this ultrarelativistic jet from a neutron star merger revealed an associated kilonova, offering new insights into how heavy elements like tellurium form in our universe.This episode highlights cutting-edge space science and the crucial role of student researchers in unlocking cosmic mysteries. Key topics: gamma-ray bursts, neutron star mergers, kilonova, heavy element formation, relativistic physics

Mars wasn't always the barren desert we see today. New research has mapped sixteen massive ancient river systems across the red planet for the first time—and the scale is staggering.Scientists at the University of Texas at Austin used orbital laser data to trace drainage basins that once carried enormous volumes of water across Mars's surface. These ancient watersheds produced roughly 28,000 cubic kilometers of sediment—evidence of rivers that flowed for potentially millions of years.But here's the mystery: where did all that water go? Mars was once warm and wet enough to sustain vast river networks, yet today it's a frozen wasteland with an atmosphere 100 times thinner than Earth's.In this episode, we explore what these newly mapped river systems tell us about Mars's vanished oceans, the catastrophic loss of its magnetic field that stripped away its atmosphere, and the climate collapse that transformed a potentially habitable world into the desolate planet we see today.The maps also raise tantalizing questions: if Mars had this much flowing water, could it have harbored life? And what can this planetary death teach us about Earth's own fragile climate?The red planet's rivers are long gone—but their ghosts remain, etched into the landscape, waiting to tell their story.