Closing In On The Comet

Rosetta 20140924This is a four-image NAVCAM mosaic taken by the Rosetta spacecraft on 24 September from a distance of 28.5 km from the centre of comet 67P/C-G. The images are processed to remove some striping and fixed noise patterns.

As the spacecraft moves closer to the comet, it is harder to create accurate mosaics because of combined effect of the comet rotation between the first and last images taken in the sequence (about 10 degrees over 20 minutes), and the fact that the spacecraft has been moving (up to a couple of km).

Image Credit: ESA

A Colossal Interaction

An interacting colossusThis picture shows a galaxy known as NGC 6872 in the constellation of Pavo (The Peacock). Its unusual shape is caused by its interactions with the smaller galaxy called IC 4970 that can be seen just above it. The pair are roughly 300 million light-years away from Earth.

NGC 6872 measures over 500,000 light-years across. It’s the second largest spiral galaxy discovered thus far. Our own galaxy, the Milky Way, measures around 100,000 light-years across.

The upper left spiral arm of NGC 6872 appears distorted and is filled with star-forming regions which appear blue on this Hubble image. That may have been be caused by IC 4970 recently (only about 130 million years ago) passing through this spiral arm. Astronomers have noted that NGC 6872 seems to be relatively sparse in terms of free hydrogen, which is the basis material for new stars. It is probable that if it weren’t for its interactions with IC 4970, NGC 6872 might not have been able to produce these new bursts of star formation.

Image Credit: NASA / ESA

A Comet’s Terrain Map

Rosetta Terrain MapThis map of the view looking toward the “belly” and part of the “head” of comet 67P/Churyumov-Gerasimenko is divided into several regions of differing types of terrain.

Based on analysis of images of the comet’s surface taken by OSIRIS, Rosetta‘s scientific imaging system, the mission science team has defined several different regions, each of which has a distinctive physical appearance.

Image Credit: ESA