Category Astronomy/Space

The Milky Way arcs into a panorama in the southern sky, taken from the Paranal Observatory, Chile. Credit: ESO/H.H. Heyer

When our galaxy was born, ~13B yrs ago, a plethora of clusters containing millions of stars emerged. But over time, they have been disappearing. However, hidden behind younger stars that were formed later, some old and dying star clusters remain, eg E 3. European astronomers have now studied this testimony to the beginnings of our galaxy.

Globular clusters are spherical-shaped or globular stellar groupings which can contain millions of stars. There are about 200 of them in the Milky Way, but few are as intriguing to astronomers as the E 3 cluster. It is 30,000 light years away, in the southern constellation of Chameleon...

This representation of Ceres’ Occator Crater in false colors shows differences in the surface composition. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

2 new studies from NASA’s Dawn spacecraft show insights about mysterious bright features found all over the dwarf planet’s surface. In one study, scientists identify this bright material as a kind of salt. The 2nd study suggests the detection of ammonia-rich clays, raising questions about how Ceres formed.

Ceres has more than 130 bright areas, and most of them are associated with impact craters. The bright material is consistent with a type of magnesium sulfate, hexahydrite.
Nathues and colleagues, using images from Dawn’s framing camera, suggest these salt-rich areas were left behind when water-ice sublimated in the past...

A diagram showing how the meteors will appear to emanate from a radiant in the constellation of Gemini, located in the east in the evening sky. Credit: Greg Smye-Rumsby / Astronomy Now

From 13 to 15 Dec, weather permitting, skywatchers across the world will be looking up as the Geminid meteor shower reaches its peak, in potentially one of the best night sky events of the year. Tens of ‘shooting stars’ or meteors may be visible each hour (the theoretical maximum under ideal conditions is about 120/hr). Meteors are the result of small (mm- to cm-sized) particles entering the Earth’s atmosphere at high speed, burning up and superheating the air around them, which then shines as a characteristic short-lived streak of light...

“Outflows” (red), regions where plumes of hot gas escape the intense nuclear burning at a star’s surface, form at the onset of convection in the helium shell of some white dwarf stars. This visualization depicts early convection on the surface of white dwarf stars of different masses. Credit: Adam Jacobs, Stony Brook University

3D simulations of double-detonation Type Ia supernovas reveal dynamic burning. Exploding stars may seem like an unlikely yardstick for measuring the vast distances of space, but astronomers have been mapping the universe for decades using stellar eruptions, supernovas, with surprising accuracy.

Type Ia supernovas – exploding white dwarf stars -are considered the most reliable distance markers for objects beyond our local group of galaxies...