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

Trumpler 14

Trompler 14This glittering star cluster that contains some of the brightest stars our galaxy. Trumpler 14 is located 8,000 light-years away in a large star-formation region called the Carina Nebula. Because the cluster is relatively young, only 500,000 years old, it has one of the highest concentrations of massive, luminous stars in the entire Milky Way.

The dark spot left of center is a blob of gas and dust seen in silhouette.

Image Credit: NASA / ESA

The Veil Nebula

Veil Nebula smallThe Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus. It’s the visible portions of the Cygnus Loop, a large but relatively faint supernova remnant. The source supernova exploded between 5,000 to 8,000 years ago, and the remnants have since expanded to cover a swath of the sky roughly 3 degrees across, about 6 times the diameter of the Full Moon.

Image Credit: NASA