Aurora on Saturn


aurora uvThis is the first image of Saturn’s aurora that was taken by the Hubble Space Telescope in 1997 when Saturn was 1.3 billion km from Earth. Saturn’s auroral displays are caused by an energetic wind of charged particles from the Sun that sweeps over the planet. Unlike the Earth’s, Saturn’s aurora is only seen in ultraviolet light. Because the UV doesn’t penetrate our atmosphere, Saturn’s aurora can only be observed from space.

Image Credit: NASA

A Galactic Merger


One from manyThis is an odd galaxy known as NGC 1487. It’s not a single galaxy but two or more galaxies in the act of merging. Each of the old galaxies has lost almost all traces of its original appearance as the stars and gas have been thrown about by gravitational interactions. Unless one of the merging galaxies is very much bigger than the other(s), galaxies are always disrupted by the violence of the merging process, so it’s essentially impossible to determine exactly what the original galaxies looked like or how many of them there were. In this case, it may be that this NGC 1487 is the merger of several dwarf galaxies that were previously part of a small group.

Although older yellow and red stars can be seen in the outer regions of the new galaxy, its general appearance is dominated by bright blue stars that probably formed in a burst of star formation triggered by the merger.

Image Credit: ESA / NASA

NGC 986


An Often Ignored BeautyThis is the spiral galaxy NGC 986 in the constellation of Fornax (The Furnace). The galaxy is about 56 million light-years away, and we see it almost perfectly face-on from Earth, allowing us to see the two main spiral arms and also a central bar-shaped structure, composed of stars and dust, which makes it a barred spiral galaxy.

Image Credit: ESO

Pictor A


Pictor AThis image combines X-ray and radio astronomy data. The Chandra X-ray image of Pictor A shows a spectacular jet that emanates from a black hole in the center of the galaxy and extends across 300,000 years toward a brilliant hotspot and a counter jet pointing in the opposite direction.

Image Credits:
X-ray: NASA / CXC / Univ. of Hertfordshire / M. Hardcastle et al.
Radio: CSIRO / ATNF / ATCA