Category Archives: Comets and Asteroids
The more NASA’s Dawn spacecraft observes of the dwarf planet Ceres the weirder it seems to get. Closer investigations of the “bright spots” first seen in Hubble images in 2003 and then in Dawn images upon approach during the first few months of 2015 show an ever-increasing cluster of smaller bright areas (eight at last count) and now a strange lone conical mountain has been found, rising 3 miles (5 km) from Ceres’ surface.
What are the origins of these features? The bright spots are only known at this point to be reflective (rather than light-emitting) substances, and the “great pyramid of Ceres” as it’s being called could be volcanic in origin… but only further investigation will tell.
Dawn will drop down to an altitude three times lower in July, after which much more detailed images will be acquired. What will be discovered then? Stay tuned…
After a brief period of silence (due to its position on the dwarf planet’s night side) NASA’s Dawn spacecraft is now sending back images from orbit around Ceres, revealing amazing details of its surface and giving another look at those mystery “bright spots” that have intrigued scientists since their discovery in 2003.
The animation above shows Ceres’ northern hemisphere as it rotated into the sunlight on April 14. The brightest bright spot can be seen in the crater at right – as Dawn was on approach earlier this year it resolved that spot into two distinct regions.
Scientists still aren’t sure exactly what those are, but soon Dawn will be getting an even better look.
ESA’s comet-chasing Rosetta mission is best known today for its two historic firsts of entering orbit around a comet and sending a lander onto the surface of said comet, in May and November of 2014 respectively. But Rosetta didn’t just go directly from its March 2, 2004 launch to comet 67P; it had to perform several flyby maneuvers beforehand with planets and asteroids on its way out to meet a comet. And now, ESA has shared many of the images acquired during those close passes during its cruise phase in a series of online albums for the public to easily access.
The image above shows the Moon beyond the hazy line of Earth’s atmosphere, acquired on March 4, 2005 during Rosetta’s first gravity-assist flyby of Earth just over a year after its launch. (Rosetta made three such passes by our planet before gathering enough velocity to make it out to 67P!)
See a list of Rosetta’s flybys below and find out how to access the albums.
The first attempt by ESA and Rosetta to hear back from Philae has turned up only radio silence – but that doesn’t necessarily mean the lander is on permanent shutdown. It may just be that it’s still too cold and dark where Philae is to have sufficiently warmed up its components for reactivation.
“It was a very early attempt; we will repeat this process until we receive a response from Philae,” said DLR (Germany’s Aerospace agency) Project Manager Stephan Ulamec. “We have to be patient.”
After landing in an as yet unconfirmed location on comet 67P on November 12, 2014, Philae performed all of its primary science tasks before running out of battery power and entering a hibernation “safe” mode. Its reawakening is anticipated by mission engineers as the comet gets closer to the Sun over the next several months.
It’s official – NASA’s Dawn spacecraft has arrived at the dwarf planet Ceres! Today, March 6 2015, at 7:39 a.m. EST (12:39 UTC) Dawn was captured by Ceres’ gravity at a distance of 38,000 miles (61,155 km). Mission controllers at JPL received a signal from the spacecraft at 8:36 a.m. EST (13:36 UTC) that Dawn was healthy and thrusting with its ion engine, indicating Dawn had entered orbit as planned.
Over the next several weeks Dawn will move into a lower orbit around Ceres, making observations along the way.
Dawn is the first spacecraft to successfully enter orbit around two worlds* and the first to orbit a dwarf planet. Its first target was the asteroid Vesta, which it orbited from July 2011 to September 2012. Now at Ceres two and a half years later, it will remain in orbit both during its primary science phase and beyond… Ceres will be Dawn’s permanent home.
“Since its discovery in 1801, Ceres was known as a planet, then an asteroid and later a dwarf planet. Now, after a journey of 3.1 billion miles and 7.5 years, Dawn calls Ceres home.”
– Marc Rayman, Mission Director and Dawn chief engineer
Congratulations Dawn and the mission team! Follow the Dawn mission news here (and of course right here on Lights in the Dark!)