Hubble spies a lonely spiral

The NASA/ESA Hubble House Telescope’s Large Discipline Digicam 3 imaged this lonely spiral galaxy known as UGC 9391.

The galaxy resides 130 million light-years from Earth within the constellation Draco close to the north celestial pole. Its star-studded spiral arms stand in splendid isolation towards a backdrop of distant galaxies, that are solely seen as vague swirls or smudges because of their huge distances from Earth. The picture additionally options some a lot brighter foreground stars nearer to residence. These shiny close by stars are ringed with diffraction spikes—distinguished spikes attributable to mild interacting with the interior workings of Hubble’s secondary mirror helps.

This picture is from a set of Hubble observations which astronomers used to assemble the “Cosmic Distance Ladder”—a set of related measurements that permit astronomers to find out how far probably the most distant astronomical objects are. Astronomical distances are solely instantly measurable for comparatively close by objects—nearer than 3,000 light-years or so. For distances past this, astronomers depend on a set of measured correlations calibrated towards close by objects.

UGC 9391 helped astronomers enhance their distance estimates by offering a pure laboratory wherein to check two measuring methods—supernova explosions and Cepheid variables. Bettering the precision of distance measurements helps astronomers quantify how shortly the universe is increasing—certainly one of Hubble’s key science objectives.