Category Archives: Comets and Asteroids
NASA’s Dawn spacecraft is just a few days away from getting snagged by the pull of Ceres, a dwarf planet existing amongst the asteroids. As it’s approaching via the slow but steady thrust of its ion engines Dawn is getting better and better images of Ceres, bringing the world’s features into focus. But on Friday, March 6 (at 7:20 a.m. EST / 12:20 UTC) it will finally feel the gentle tug of Ceres’ gravity and will soon become the first spacecraft to enter orbit around two different targets.
“Dawn is about to make history,” said Robert Mase, project manager for the Dawn mission at NASA’s Jet Propulsion Laboratory in Pasadena, California. “Our team is ready and eager to find out what Ceres has in store for us.”
One of the biggest mysteries that has arisen during Dawn’s approach to Ceres is the true identity of the two bright spots located within a crater on its northern hemisphere. Shining like the eyes of some nocturnal creature, the bright region was first seen in Hubble images captured in December 2003. Now Dawn has gotten close enough to resolve it into two separate spots, one brighter than the other… but not much more is known about its true nature yet. Read the rest of this entry
Here’s your weekly Ceres update! The dwarf planet’s features are coming into better and better focus for the approaching Dawn spacecraft, which will be captured by Ceres’ gravity on March 6. The image above is yet another “best-ever” of Ceres (as will be each one we see now), captured on Feb. 19, 2015, from a distance of about 29,000 miles (46,000 km).
This was one of a trio of images from Dawn released today. The others can be seen below, including one that shows the intriguing bright spot that has been observed for over a decade.
On Saturday, Feb. 14, 2015, the Rosetta spacecraft performed a bit of a barnstorming act, swooping low over the surface of comet 67P/C-G in the first dedicated close pass of its mission. It came within a scant 6 km (3.7 miles) of the comet’s surface at 12:41 GMT. The image above is a mosaic of four individual NavCam images acquired just shortly afterwards, when Rosetta was about 8.9 km from the comet.
Higher-resolution OSIRIS images should be downlinked from the spacecraft within the next few days.
The view above looks across much of the Imhotep region along the flat bottom of comet 67P’s larger lobe. (See a map of 67P’s named regions here.) At the top is the flat “plain” where the Cheops boulder cluster can be seen – the largest of which, Cheops itself, is 45 meters (148 feet) across.
After the close pass Rosetta headed out to a distance of about 253 km (157 miles) before beginning preparations to approach closer again. Over the course of Rosetta’s mission this year flybys will be the “new normal,” but none will be as close as the Feb. 14 pass.
Watch a video from ESA about the close pass below, and find more images from the flyby in my article on Universe Today here.
Won’t you look at that! Here’s a view of Ceres captured by NASA’s Dawn spacecraft on Feb. 12, 2015, from a distance of about 52,000 miles (83,000 km). No longer just a grey sphere with some vague bright spots, actual features can now be resolved – craters, mountains, and scarps that quite literally no one has ever seen before! Fantastic!
Two images were captured by Dawn’s framing camera as Ceres rotated within view over the course of its 9-hour day. See both below:
And the show is on! The dramatic images above show the actively jetting comet 67P/Churyumov-Gerasimenko on Jan. 31 and Feb. 3, imaged by Rosetta’s NavCam from a distance of about 28 km (17 miles). Each is a mosaic of four separate NavCam acquisitions, and I adjusted and tinted them in Photoshop to further enhance the jets’ visibility. (You can view the original image mosaics here and here.)
The small bright spots and flecks in the images are bits of icy debris and dust that have been ejected from the comet. In the second image you can see what looks like deflection of the jets from the comet’s lower lobe off the underside of the upper lobe as well as a shadow of the upper section being cast down through the reflective icy spray.
These views are just a hint at what’s in store; 67P’s jet activity will only be increasing in the coming weeks and months and, this Saturday, Rosetta will be swooping down for an extreme close pass over its surface. Luckily for us we get to experience the adventure vicariously through Rosetta!
This is the second animation from Dawn this year showing Ceres rotating, and at 43 pixels across the images are officially the best ever obtained!
NASA’s Dawn spacecraft is now on final approach to the 590-mile-wide dwarf planet Ceres, the largest world in the main asteroid belt and the biggest object in the inner Solar System that has yet to be explored closely. And, based on what one Dawn mission scientist has said, Ceres could very well be called the Solar System’s “hipster planet.”
“Ceres is a ‘planet’ that you’ve probably never heard of,” said Robert Mase, Dawn project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California. “We’re excited to learn all about it with Dawn and share our discoveries with the world.”
(Hmm… so does this mean Ceres has gone “mainstream?”)