ESA Rosetta Mission: Sneak peek at Comet 67/P's "underside" - Cheops

ESA Rosetta NavCam captures a four-image mosaic of 67P/Churyumov-Gerasimenko on Jan. 16, 2015. 

Credit: ESA/Rosetta /NAVCAM – CC BY-SA IGO 3.0

A particularly dramatic view of comet 67P/C-G due to the angle of solar illumination, this is a mosaic made from four images acquired by ESA Rosetta's NavCam on January 16, 2015, from a distance of 28.4 km (17.6 miles).

The assembled image shows the larger "bottom" lobe of comet 67/P, with a flat region called Imhotep along the left side and, on the lower right, the transition area stretching up to the comet's smaller "head" lobe.

Outgassing jets can be seen as faint streaks at the upper right, and ejected dust grains show up as bright specks above its surface.

Also in this view is one of 67P's larger boulders, a somewhat pyramid-shaped rock dubbed "Cheops."

Position of the Cheops boulder on 67P 

Credit: ESA /Rosetta /Navcam

One in a cluster of boulders on 67P's "underside," Cheops is about 45 meters wide and 25 meters high (148 x 82 feet).

When it was first observed in Rosetta images Cheops and the nearby cluster reminded scientists of the pyramids at Giza in Egypt, and so it was named for the largest of those pyramids, the Great Pyramid, a tomb for the pharaoh Cheops (the Hellenised name for Khufu) built around 2,550 BCE.

Scientists are still working to determine the nature of 67P's boulders. It's not yet known what they are made of or how they came to be where they are observed today.

Did they fall into their current positions? Or were they exposed upwards from below as a result of the comet's activity? And why do they have alternating rough and smooth areas on their surfaces?

"It almost looks as if loose dust covering the surface of the comet has settled in the boulder's cracks, but, of course, it is much too early to be sure," said OSIRIS Principal Investigator Holger Sierks from the Max Planck Institute for Solar System Research (MPS) in Germany.

As comet 67P approaches perihelion over the course of the next six months we will get to see firsthand via Rosetta what sorts of changes occur to its surface features, including office-building-sized boulders like Cheops.

OSIRIS image of Cheops acquired on Sept. 19, 2014. 

Credit: ESA /Rosetta /MPS for OSIRIS Team MPS /UPD /LAM /IAA /SSO /INTA /UPM /DASP /IDA

NASA Mars Curiosity Rover: MAHLI Captures a mosaic of Mars

A mosaic of MSL MAHLI images acquired on Sol 613. CLICK on the photo to see the full image

Credit: NASA /JPL-Caltech /MSSS

This is Curiosity's latest "selfie," a mosaic made up of about a dozen images acquired with the rover's Mars Hand Lens Imager (MAHLI) instrument on April 27-28, 2014 (Sol 613).

The 5.5-km-high Mount Sharp (Aeolis Mons) rising in the background.

There are plenty of discrepancies in the mosaic tiling but, some say, it imparts some character to Curiosity.

Visible in the mosaic are Curiosity's cylindrical RUHF antenna and a bit of her Radioisotope Thermoelectric Generator (RTG) visible in the lower center.

NOAO Mosaic CCD camera Image: Eagle Nebula

This wide-field image of the Eagle Nebula was taken at the National Science Foundation's 0.9-meter telescope on Kitt Peak with the NOAO Mosaic CCD camera.

Located in the constellation of Serpens, the Serpent, the Eagle Nebula is a very luminous open cluster of stars surrounded by dust and gas. 

The three pillars at the center of the image, made famous in an image by the Hubble Space Telescope, are being sculpted by the intense radiation from the hot stars in the cluster.

This image was created by combining emission-line images in Hydrogen-alpha (green), Oxygen [O III] (blue) and Sulfur [S II] (red).

Image: T.A.Rector (NRAO/AUI/NSF and NOAO/AURA/NSF) and B.A.Wolpa (NOAO/AURA/NSF)

Harvard Astronomer Pays Tribute to Van Gogh with Hubble Mosaic

One night, Harvard astronomer Alex Parker was camped out at the telescope for a spot of star-gazing, and found himself facing a long, dry period of waiting for the clouds to clear.

To pass the time, he started playing around with various images from the Hubble Space Telescope, and ended up assembling them into a colorful mosaic.

The resulting image? A recreation of Vincent van Gogh's most famous painting, "Starry Night".

Alex Parker, a postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics’ Institute for Theory and Computation, has created several astronomical videos on his own time and posted them on the Internet. 

His latest video depicts the 2,299 planet candidates Kepler has found since it began searching for planets around stars in 2009. 

According to sources "Parker used photo-mosaicing software to assemble the digital collage."

He had been thinking about using Hubble images to make a mosaic for awhile, since the telescope's 22nd anniversary was approaching; he just needed the right circumstances to find the time -- a cloudy night.

"Observing can be all over the map," Parker reported about his artistic endeavour. "You will be shut out by clouds on some nights, have to evacuate the mountain because of high winds and ice on other nights, and other times there isn't a moment to pause because you're taking data at such a high rate all night."