Comets are time capsules from the dawn of the solar system, but their solid nuclei are almost always hidden behind a thick veil of dust. Because comet 2P/Encke has unusually low dust activity, astronomers managed a rare feat: looking straight at its bare nucleus from the ground, in thermal infrared, and measuring an elongated, potato-shaped body a few kilometers across, warmed to about 55 degrees Celsius. We explain the finding, and why the shape and size rest on a model.

Some cosmic explosions are impostors: they look like supernovae, but the star survives and sometimes keeps erupting. The impostor AT 2016blu has flared roughly every 113 days for over a decade. Now astronomers, helped by amateur observers who timed the outburst, have caught it in X-rays for the first time, revealing the culprit: not a lone star erupting, but a hidden compact companion feeding on a giant star at each close passage. We explain the finding and what’s solid versus still open. To access the full content, become a member by clicking the link below.

Little red dots are among JWST’s strangest finds: compact crimson objects that hint at feeding black holes yet stay oddly quiet in X-rays and radio. Most are too distant to study in detail, so astronomers turned to a nearby cousin. Mining three decades of radio data, they found that this local little red dot carries a compact, slowly brightening radio signal best explained by a feeding black hole, not a starburst. We explain the finding, and why the black-hole origin is inferred by elimination. To access the full content, become a member by clicking the link below.

En 1976, el módulo Viking 2 posó en Marte un sismómetro que durante casi medio siglo se consideró un fracaso: iba atornillado a la cubierta de la nave, y el viento marciano la sacudía tanto que ahogaba cualquier temblor del suelo. Ahora, un reanálisis del equipo de Constantinos Charalambous y Benjamin Fernando, apoyado en lo aprendido con la misión InSight, rescata de aquel ruido una decena de eventos candidatos que no parecen ni viento ni vibración del módulo: posibles terremotos marcianos que quedaron registrados sin que nadie lo notara. Para acceder al contenido completo, hazte miembro haciendo clic en el enlace que aparece a continuación.