Ever since it was first spotted by Hubble in 2003, the nature of the curious bright spot on Ceres has been an intriguing mystery for scientists. And even as NASA’s Dawn spacecraft approached the dwarf planet earlier this year the bright spot continued to mystify, gradually resolving into first two and then multiple, separate spots as Dawn got closer and closer. Now in its first mapping orbit of Ceres, Dawn’s view of the bright region is the best it’s ever been – and we’re still not quite sure what it is.
One thing scientists are fairly certain of, though, is that it’s an area of reflective material.
At 3:34 p.m. EDT (19:34 UTC) today, April 30, 2015, after more than ten years in space – and four of them in orbit – the MESSENGER spacecraft’s operational life came to a conclusive end when it impacted the surface of Mercury, as planned.
After revealing the surface of the innermost planet like no mission ever before, MESSENGER’s last act was to contribute one more crater to Mercury’s battered and Sun-scoured face.
The impact site was out of view (and thus out of communication range) of Earth at the time, but based on the spacecraft’s trajectory and time when its signal was last received it’s known that it very likely struck a low ridge just north of a basin named Shakespeare, near 54.5 degrees north latitude and 210.1 degrees east longitude.
Colliding at a velocity of 8,700 mph, MESSENGER’s impact is estimated to have made a crater about 52 feet (16 meters) across.
“Going out with a bang as it impacts the surface of Mercury, we are celebrating MESSENGER as more than a successful mission,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate. “The MESSENGER mission will continue to provide scientists with a bonanza of new results as we begin the next phase of this mission – analyzing the exciting data already in the archives, and unraveling the mysteries of Mercury.”
See MESSENGER’s very last transmitted image below.
As the ice-encrusted moon Enceladus makes it way along its orbit around Saturn it gets repeatedly squeezed by the giant planet’s gravity, like a frozen stress ball with water-filled insides. This constant squeezing and relaxing generates friction heat in the moon’s crust, which could be responsible for keeping some of its internal water liquid and spraying it out into space from long canyons that cut across its southern pole. And sometimes more ice gets shot out than at other times, forming a trail of long tendrils that stretch into the “E” ring – a hazy, diffuse doughnut around Saturn made from Enceladus’ icy exhaust.
These tendrils had been observed by the Cassini spacecraft since 2006, but only now have they been positively confirmed to be the results of specific geysers on the 318-mile-wide moon.
In a historic first – just one of many that will be made over the next several months, to be sure! – the New Horizons spacecraft captured its first color image of Pluto and its partner/satellite Charon on April 9 from a distance of 71 million miles – about equivalent to that between Venus and the Sun. The orange blobs above are the two worlds locked in an orbital dance a mere 12,200 miles apart… that’s 20 times less than the distance between Earth and the Moon!
The image was captured with New Horizons’ “Ralph” instrument, a Multispectral Visible Imaging Camera (MVIC) built for the mission by Ball Aerospace (which is a spinoff of the same company that became famous in the U.S. for its glass canning jars.)
Ralph is one of six science instruments aboard New Horizons; it is paired with “Alice,” an ultraviolet imaging camera. (Think Ralph and Alice Kramden.) When New Horizons makes its close pass by Pluto and Charon on July 14 these cameras will capture details of the icy worlds like never before seen.
The 72-mile (116-km) -wide crater Adedin is seen at an oblique angle in this mosaic made from images acquired by NASA’s MESSENGER spacecraft. The angle highlights the crater’s central peak complex which surrounds a shallow depression that could have a volcanic origin, as well as fine cracks in the floor of its basin and a slumped and terraced section of its far wall. The crater was named after the Bangladeshi painter Zainul Abedin (1914-1976).
And I suggest you enjoy it – it will be one of the last images we see from MESSENGER!
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.