NATIONAL GEOGRAPHIC'S SPACE PICTURES THIS WEEK LXXVIII

Best Space Photos of the Week: Blue Fire, Raindrop Dunes
By Andrew Fazekas, National Geographic News, 4 October 2013.

A solar display and northern lights are seen this week, along with other sky-watching delights.

1. Blue Fire

Resembling a fiery blue marble, the sun is captured in this dramatic extreme-ultraviolet-light image by NASA's STEREO spacecraft on September 27.

While the sun is at its maximum level of activity on its 11-year sunspot cycle, its surface the past month appears strangely quiet, with few solar storms and nearly no brighter active regions.

Astronomers theorize that this solar cycle's maximum may in fact be a double peak and that we are between peaks now. They also think that both sunspot and storm activity may pick up later this fall or in the winter early next year.

2. Cosmic Lighthouse

Photograph by Pal Jakobsen, National Geographic Your Shot

A lighthouse in northern Norway is illuminated by the green glow of northern lights dancing in the skies above Narvick, Norway, on March 20.

Comet Pan-STARRS appears almost lost in the ghostly glow, seen with its tiny fuzzy tail in the above image, near the horizon just to the left of the lighthouse base.

3. Lagoon Nebula

Photograph by Tobias Kramer, National Geographic Your Shot

The colourful stellar nursery known as the Lagoon nebula is captured through a backyard telescope on August 1.

Located some 5,000 light-years from Earth in the southern constellation Sagittarius, this giant cloud of gas and dust stretches some 100 light-years across and is faintly visible with the naked eye from dark locations.

4. Raindrop Dunes

An infrared view of dark sand dunes on the floor of one of the oldest craters on Mars was captured by NASA's Mars Reconnaissance Orbiter on October 2.

Such raindrop-shaped sand dunes are made of grains of a volcanic rock, basalt, and are among the most widespread wind-formed features on the red planet.

5. Stellar Relic

The final remnants of a sun-like star blown out in a blue, hazy disk of gas and dust is captured by the Hubble Space Telescope.

An Earth-size white dwarf is all that remains of the progenitor star inside this planetary nebula known as NGC 2452, in the southern constellation Puppis.

Astronomers estimate that approximately 5 billion years from now, the same fate awaits our sun.

[Source: National Geographic News. Edited.]