Jim Green, who is director of the Planetary Science Division at NASA headquarters, clearly loves his job, and he got so excited during Thursday's news conference that he kept interchanging Enceladus with Europa in his remarks. Both were in play during the discussion, and the context made it clear what he intended, but I always get a kick out of seeing that kind of enthusiasm showing forth in scientists and academics. It's a reminder of why they got involved in the first place, and for that matter, what drew me into writing about the field myself. The news delivered in the press conference and through two new papers involves two older space missions that are driving planning for yet a third, the Europa Clipper mission, a Jupiter orbiter that is still in the design and planning stages. And with Cassini in its final months of operation, it's fitting that a Cassini flyby through the Enceladus plumes in 2015 should result in what Cassini project scientist Linda Spilker (JPL) called a...

Astronomical investigations can overlap in extremely helpful ways. Consider the Dark Energy Survey, which examines some 12 percent of the sky in an attempt to learn more about whatever force is accelerating the expansion of the universe. DES is trying to map hundreds of millions of galaxies and identify thousands of supernovae while looking for patterns in cosmic structure, using a 570-Megapixel digital camera, DECam, mounted on the Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory (Chile). What DES produces are thousands of images -- its initial search uncovered 1.1 billion candidate objects, most of which are galaxies or background stars. But among the objects are some that move in successive observations, the signature of objects in our Solar System. David Gerdes (University of Michigan) was able to find what appears to be a dwarf planet within the dataset. Called 2014 UZ224 and informally known as DeeDee (for Distant Dwarf), the object has now been characterized...

NASA is to discuss new findings about ocean worlds in our Solar System in a news conference at 1400 EDT (1800 UTC) on Thursday. The prospects for oceans in the outer system are surprisingly varied, ranging from the strong evidence of a subsurface, salty ocean on Europa to other Jovian moons like Ganymede and Callisto, and of course, Saturn's intriguing moon Enceladus. Titan is thought to have a salty ocean perhaps 50 kilometers below its ice shell, while there are also possible ocean venues on Mimas, Triton and even Pluto. The news briefing participants will be: Thomas Zurbuchen, associate administrator, Science Mission Directorate at NASA Headquarters in Washington Jim Green, director, Planetary Science Division at NASA Headquarters Mary Voytek, astrobiology senior scientist at NASA Headquarters Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California Hunter Waite, Cassini Ion and Neutral Mass Spectrometer (INMS) team lead at the Southwest...

The attitude you bring to a star field changes everything. When I was a kid trying to figure out how to use a small telescope, I scanned the usual suspects -- the Moon, Saturn and its rings, the Galilean satellites of Jupiter -- all the while planning to branch out into major wonders like M31 or the Ring Nebula in Lyra. But when I turned to deep sky objects, what I discovered was that I could see little more than faint smudges -- I was using no more than a 3-inch reflector. It was a disappointment for a while, until I accepted the limitations of my equipment. And then I became a cataloger of faint smudges, as avidly tracking down celestial objects as any stamp collector sorting through new finds. A patient uncle showed me how to look slightly away from the object I sought, to pick it up in peripheral vision. I began keeping notebooks listing my first glimpses of various nebulae and clusters. So many celestial objects were out of reach, but somehow a field of stars became wondrous not...

We’re getting a few clues about the nature of planet migration in the early Solar System thanks to a class of objects being described as ‘blue binaries.’ Cold Classical Kuiper Belt Objects (CCKBOs) are generally reddish, but a population of widely separated binaries has now been identified that is thought to have originated in the inner edges of the Kuiper Belt. The paper reporting on this work argues that these objects were pushed out a distance of over 4 AU to their present location among the CCKBOs as the result of gravitational interactions with Neptune billions of years ago, a movement induced by the migration of the planet from 20 to 30 AU. If so, we can draw some conclusions about that migration, and we’re reminded in the process of how rich the Kuiper Belt is in objects of different origins. Led by Wes Fraser (Queen’s University, Belfast), the study used data drawn from the Gemini North instrument and the Canada-France-Hawaii Telescope, both on Mauna Kea, as part of a project...

With my own memories of the July 4, 1997 landing of Mars Pathfinder at Chryse Planitia as fresh as yesterday, it's hard to believe that we are looking at the 20th anniversary of rover operations on the planet. But as the Curiosity rover continues its travels and we look toward the Mars 2020 rover mission, we're also taking a much longer look ahead at the worlds where life may be more likely to be found, the icy moons of Jupiter and Saturn. Ponder this: Testing at the Jet Propulsion Laboratory is showing that ice grains in conditions like we will encounter on places like Enceladus or Europa can behave like sand dunes. That means fine grains that could stall an improperly designed rover, leading NASA engineers to begin rethinking designs harking back to the early days of Moon exploration, lightweight commercial wheels attached to a flexible chassis, a system that has worked for a variety of missions but will need adjustment for future work. The rovers that use these systems will, in...

An obscure instrument called a blink comparator became world famous following Clyde Tombaugh's discovery of Pluto in 1930. It was by rapidly switching between astronomical photographs that the young Tombaugh was able to compare objects in the field of view where 'Planet X' was presumed to hide. Pluto turned out to be a good deal smaller than Percival Lowell had imagined, leading to thoughts of still more distant planets, but for a time the new planet was best known as a faint dot on a series of plates, moving against a fixed field of stars. Image: Clyde Tombaugh at the Blink Comparator five years after the Pluto discovery. Credit: Lowell Observatory Archives. All of this is wonderfully told in Michael Byers' 2010 novel Percival's Planet (Henry Holt and Co.), which draws on Tombaugh's story and depicts the entire Lowell Observatory scene in his time there (see A Tour de Force of Planetary Discovery for my review of the book). Or if you want the inside view, Tombaugh's own Out of the...