It took more than 200 years to find out, but a globular cluster discovered in 1778 by comet-hunter Charles Messier turned out to be the first such star swarm located outside the Milky Way. As astronomers discovered in 1994, the cluster, known as M54 in Messier’s famous catalogue, is actually located some 90,000 light years away in the Sagittarius Dwarf Elliptical Galaxy, about three times farther than Earth is from the center of the Milky Way. But if you wait a while – a very long while – M54 will become part of Earth’s galaxy as the Sagittarius dwarf slowly merges with the larger body. This photograph of M54 was taken in 2011 by the Hubble Space Telescope’s Advanced Camera for Surveys.
The eerie glow of a dead star, which exploded long ago as a supernova, reveals itself in this NASA Hubble Space Telescope image of the Crab Nebula in the constellation of Taurus. But don’t be fooled. The ghoulish-looking object still has a pulse. Buried at its centre is the star’s telltale heart — a neutron star which beats with rhythmic precision.
The subject of this NASA/ESA Hubble Space Telescope image is known as NGC 3597. It is the product of a collision between two good-sized galaxies, and is slowly evolving to become a giant elliptical galaxy. This type of galaxy has grown more and more common as the universe has evolved, with initially small galaxies merging and progressively building up into larger galactic structures over time.
In this new image of the nebula Messier 78, young stars cast a bluish pall over their surroundings, while red fledgling stars peer out from their cocoons of cosmic dust. ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA) sees near-infrared light, which passes right through dust, permitting astronomers to probe deep into the heart of the stellar environment.