The ways astronomers find to wrest new findings from raw data never ceases to amaze me. This news release from the Max-Planck-Institut für Radioastronomie focuses on a new way to weigh the planets in our Solar System by using signals from pulsars. The method flows out of work on pulsar timing that has been used in the hunt for gravitational waves and has implications not just for the known planets but for detecting hitherto unknown objects in our system. Pulsar timing supplements earlier ways of weighing planets by measuring their effect on spacecraft flown past them, or extrapolating information from the orbits of their moons. And it seems to be hugely sensitive, to just 0.003 percent of the mass of the Earth and one ten-millionth of Jupiter's mass. "This is first time anyone has weighed entire planetary systems - planets with their moons and rings," says team leader Dr. David Champion (MPIfR). "In addition, we can provide an independent check on previous results, which is great for...

It's almost exhilarating to find that the volume of space studied in new work on the Trojan asteroids near Neptune includes an area through which New Horizons will pass on its way to Pluto/Charon. This used to seem like an all but unknowable region until Voyager 2 made its Neptune pass, and although it's been a long time since we've had a spacecraft there, we're learning much more about the outer system from Earth-based resources, as the discovery of objects like Eris and Sedna makes clear. We can surely look forward to more surprises as New Horizons moves toward its 2015 flyby and pushes on into the Kuiper Belt. The latest find, based on data from the Subaru Telescope in Hawaii and the Magellan telescopes in Chile, is the first Trojan asteroid found at Neptune's L5 Lagrangian point. Both the L4 and L5 Lagrangian points, 60 degrees ahead of and behind the planet, are stable, meaning that objects tend to collect there over time. Six Neptune Trojans are known in the L4 region, but...

Before I move into today's story on Titan, I want to mention that those of us who weren't able to attend the ongoing Second International Symposium on Solar Sailing (ISSS 2010) can take heart in the fact that selected papers from the proceedings have been quickly published online. Conferences vary tremendously in the resources they make available during and after the event, but the ISSS organizers are obviously intent on wide distribution of these interesting talks. Let's hope those papers not yet included will find their way online in coming days. TZF's Pat Galea has posted a number of photos from day one of the event on Flickr, including this shot of JAXA's Osamu Mori delivering an early talk on the IKAROS mission. Project leader for IKAROS, this man is a solar sail pioneer. For those of you who've asked, the focus of ISSS 2010 is indeed near-term, although several longer-range papers will be presented. With our first operational solar sail only recently launched, this is a time to...

We learned in May that Jupiter's South Equatorial Belt (SEB) had disappeared, an event that still has skywatchers puzzled, though it's not without precedent. In fact, the SEB fades out every now and then, with recent fadings in 1989, 1993 and 2010, and we can expect an outburst of storms and vortices when the enigmatic belt returns, probably within the next two years, based on historical precedent. All of which puts the spotlight on Juno, a Jupiter mission intended for launch in August of 2011. Juno is all about the giant planet's core, its magnetic field, its auroras and the amount of water and ammonia in its atmosphere. Juno's Jovian Science Maybe Juno will tell us whether the disappearance of the South Equatorial Belt is the result of ammonia cirrus forming on top and hiding the belt from view. But there is much more to learn. Hydrogen gas deep in Jupiter's atmosphere is pressed into metallic hydrogen, a fluid that acts like an electrically conducting metal and is thought to be...

The idea of 'Nemesis,' a hypothetical dark companion to the Sun, won't quite go away, and it's possible that the WISE mission may help us either identify such an object or else demonstrate that it's not there. The idea is simple enough: Sol's companion would perturb the Oort Cloud in its orbit, causing comets to enter the inner Solar System, thus increasing the likelihood of an impact with the Earth. Throw in an apparent periodicity in extinction events first described back in 1984 and you have an intriguing case. But Adrian Melott (University of Kansas) and Richard Bambach (Smithsonian Institution) have reconsidered Nemesis in terms of extinction events in a new paper, one that looks at the timing of these incidents in light of the movements of Nemesis over time. They extend the original 26 million year extinction periodicity slightly, to 27 million years, and are careful to note that there is no consensus on the matter among paleontologists. But the real question they tackle is...

Centauri Dreams readers should know the name Stuart Atkinson, whose excellent Cumbrian Sky site I've linked to before. I don't have many occasions to reproduce poetry in these pages (although I did quote some lines from Coleridge's 'Kubla Khan' in honor of Huygens' landing), but when I saw what Stuart had sent in to ESA's Rosetta team, I knew I had to highlight it here. Rosetta's encounter with the asteroid 21 Lutetia should bring out a bit of the poet in all of us, but Stuart nails what I felt: For all these years you were merely A smear of light through our telescopes On the clearest, coldest night; a hint Of a glint, just a few pixels wide On even your most perfectly-framed portraits. But now, now we see you! Swimming out of the dark - a great Stone shark, your star-tanned skin pitted And pocked, scarred after aeons of drifting Silently through the endless ocean of space. Here on Earth our faces lit up as we saw You clearly for the first time; eyes wide With wonder we traced the...

Suppose for a moment that you have some novel ideas about astrobiology on Io. The idea seems extreme, but there are scientists who argue for the notion, as we'll see in a moment. In any case, if you wanted to observe Io, how would you go about it? The best solution is a spacecraft, as it was when Voyager 2 sped through the Jupiter system and discovered what tidal effects can do to a small moon. The Galileo probe, despite the failure of its high-gain antenna, was able to send up-close data about both Europa and Io, confirming that the latter's volcanic activity was 100 times greater than what we experience on Earth. And then there was Cassini's lovely view. Image: Gliding past Jupiter at the turn of the millennium, the Cassini spacecraft captured this awe inspiring view of active Io with the largest gas giant as a backdrop, Credit: Cassini Imaging Team, Cassini Project, NASA. But the Voyagers are now close to leaving the Solar System, while Galileo was sent to its destruction in the...

Finding life on Mars would be a huge accomplishment, but finding life on Titan would be a fundamentally different kind of discovery. Martian life might well be related to us because of the exchange of materials between our two worlds, the inevitable result of planetary impacts and the scattering of debris. But Titan is a far more unearthly place than Mars, its chemistry exotic, its climate seemingly beyond the range of any life form we have ever discovered. Life on Titan should be evidence of that 'second genesis' planetary scientists dream of identifying. Image: This artist concept shows a mirror-smooth lake on the surface of the smoggy moon Titan. Cassini scientists have concluded that at least one of the large lakes observed on Saturn's moon Titan contains liquid hydrocarbons, and have positively identified ethane. This result makes Titan the only place in our solar system beyond Earth known to have liquid on its surface. Credit: NASA/JPL. Now we have two papers based on Cassini...

Ralph McNutt's contributions to interstellar mission studies are long-term and ongoing. We've looked at the Innovative Interstellar Explorer concept he has been studying at the Applied Physics Laboratory (Johns Hopkins), but IIE itself rose out of earlier design studies for a spacecraft that would penetrate the heliopause to reach true interstellar space. One possibility for that earlier probe was a 'Sun-diver' maneuver, a close pass by the Sun to gain a gravitational slingshot effect, followed by an additional kick from an onboard booster. The thinking a few years back was to reach 1000 AU in less than fifty years, but Innovative Interstellar Explorer has lost the Sun-diver maneuver and focuses on a more realistic 200 AU, as part of a NASA Vision Mission study that contemplates a gravitational assist at Jupiter and the use of radioisotope electric propulsion. IIE is subject to the same funding constraints as any other mission of this nature but it's well worth perusing its specs on...

Recently we've been talking about long-distance repair, and how any probe launched beyond the Solar System is going to have to fix its own problems rather than relying solely on transmissions from Earth. New Horizons, halfway to Pluto/Charon in terms of distance, isn't yet in that category. It's going to eventually make its way into the Kuiper Belt, but for now, it's close enough for controllers to wake it up periodically for checks. In fact, the next wakeup call, which comes tomorrow, begins a nine-week period of rigorous tests. Long-term missions like New Horizon demand annual checkouts, and this one (as opposed to last year's) is to be comprehensive, ranging from conducting heliospheric cruise science to uploading a series of code enhancements and bug fixes to the spacecraft's fault protection software. The spacecraft's backup systems will be checked and its seven scientific instruments re-calibrated. Principal investigator Alan Stern describes the process in his latest report. I...

Raw images from Cassini's Enceladus encounter yesterday are becoming available, the most fascinating of which show the view of the plumes as the spacecraft approached the moon from the night side. And check the image below, which is an extraordinary combination of Cassini targets the like of which I never thought I would see. At the bottom of the image, darkened almost to invisibility, is Enceladus' south pole as the spacecraft speeds over its surface (click on the image to enlarge). Swinging into view beyond it are Saturn's rings and Titan, its atmosphere clearly visible. Cassini will make a Titan flyby late this evening, in the early hours of May 20 UTC, this time passing to within 1400 kilometers of the surface in a study that will fill out Titan's thermal map. Enceladus and Titan are so aligned that Cassini will be able to make this second flyby with no additional maneuvering required. By studying the gravitational pull on the spacecraft, researchers hope to learn more about...

I love what William Bains (University of Cambridge) has to say about extraterrestrial life and how it might appear to us. "Wouldn't it be sad if the most alien things we found in the galaxy were just like us, but blue and with tails?" He's thinking, of course, of some science fiction evocations of aliens and their general similarities to our own species, perhaps the result of Hollywood budgetary constraints as much as lack of imagination. But Bains is interested in alien life for more than cinematic reasons. He's looking hard at Titan, and envisioning what life there might look like. Image: A flat, calm, liquid methane-ethane lake on Titan is depicted in this artist's concept. Copyright 2008 Karl Kofoed. Life on Titan would be, by our standards, a bit unusual. Says Bains: "Life needs a liquid; even the driest desert plant on Earth needs water for its metabolism to work. So, if life were to exist on Titan, it must have blood based on liquid methane, not water. That means its whole...

A new instrument that lets us look deeper into things almost always changes the game. Such an instrument is CRIRES, the Cryogenic High-Resolution Infrared Echelle Spectrograph. Now operational at the Very Large Telescope, CRIRES has already done yeoman work on Pluto, and has now been used to study the atmosphere of Neptune's large moon Triton in more detail than ever before. The result: A new understanding of Triton's carbon monoxide, whose existence in its upper surface layer is now confirmed and shown to be an icy 'film' that, over time, adds to the atmosphere. Image: Artist's impression of how Triton, Neptune's largest moon, might look from high above its surface. The distant Sun appears at the upper-left and the blue crescent of Neptune right of centre. Using the CRIRES instrument on ESO's Very Large Telescope, a team of astronomers has been able to see that the summer is in full swing in Triton's southern hemisphere. Credit: ESO/L. Calçada. It should come as no surprise that...

I know I should be staggered by everything about the Large Hadron Collider, but frankly, what really has me jazzed this morning is that I'm writing this with a window on one side of my screen showing a live webcast from CERN and another in an upper corner showing a Saturnian moon. There is something truly science fictional at being able to follow ongoing events both here and in space from a PC fed by a worldwide dataflow, and what events they are. The LHC is emphatically in business. Following the successful collision of two 3.5 teraelectronvolt beams (1106 GMT), CERN director general Rolf Heuer said the obvious: "It's a great day to be a particle physicist." Remarkable things will come out of the LHC, and it's stunning to see the quality of data flowing out of CERN from events that are no more than an hour old, a tribute to the quality of the installation and the team behind it. I'm keeping a CERN window open on my (wide) screen, and the Twitter flow via #LHC is great fun -- much...

Live by the cloud, die by the cloud. At least, that's the way it felt this morning when I realized Gmail was down, and along with it, several emails with pointers to stories I had planned to look at for possible use today. But let's talk about a different kind of cloud, for we still have the interesting news out of UC-Berkeley about what some reports are calling 'helium rain' on Jupiter. That's a colorful way to describe an exotic process, but it may not be the best analogy given the difference between Earth's comparatively gentle rainfall and the hellish conditions where neon 'rain' might fall. After all, this is work aimed at creating models of planetary interiors, in this case a gas giant where helium forms droplets between 10,000 and 13,000 kilometers below the tops of Jupiter's hydrogen clouds. Down in that realm pressures and temperatures reach absurd levels and both hydrogen and helium act like fluids. What we're calling 'rain' then is actually made up of drops of fluid helium...

One of the things we need to learn about the Alpha Centauri stars is whether Proxima Centauri is gravitationally bound to Centauri A and B. Much hinges on the issue, for if Proxima is merely passing in the night, then whatever disruptive effect it may have upon an outer halo of comets around the Centauri stars would be a one-shot affair. On the other hand, if Proxima is a stable part of this system, then it may send comets laden with volatiles into whatever planetary systems are around Centauri A and B. Proxima might be, in other words, the difference between dry rocky worlds and planets with abundant water, with all that implies about the possibilities for life. We've seen the same kind of thinking applied to our own Solar System in the form of the star dubbed 'Nemesis.' As the theory goes, Nemesis could be a red or perhaps a brown dwarf that could account for what seems to be a periodicity in terms of extinction events on Earth. Disrupting cometary orbits in the Oort Cloud, such an...

Titan's Sikun Labyrinthus is a an area of connected valleys and ridges that bears a certain similarity to features on Earth. The area appears analogous to what we call 'karst topography,' created on our planet when layers of bedrock are dissolved by water, to leave rock outcroppings and sinkholes. The Darai Hills of Papua New Guinea are an example, as are the White Canyon of Utah and the Cockpit Country of Jamaica. Liquid methane and ethane may be what is producing such landscapes on Titan, but the processes seem familiar indeed. Which brings us to Mike Malaska, without whose insights we might not be talking about this. Malaska is an organic chemist out of Chapel Hill NC who approached Jani Radebaugh (Brigham Young University) about a potential collaboration regarding Titan. Malaska works with visualizing NASA data and shares his results with contributors on unmannedspaceflight.com, where amateur astronomers and space exploration enthusiasts regularly discuss the latest findings. The...

Although we've been preoccupied largely with theoretical matters this week, I don't want it to close without reference to the new Cassini imagery of Enceladus. This shot was made at a phase angle of 145 degrees when Cassini was about 14,000 kilometers from Enceladus, during the flyby of November 21. The remarkable jets spraying from the fractured surface in the south polar region are clearly visible. Image: Dramatic plumes, both large and small, spray water ice out from many locations along the famed "tiger stripes" near the south pole of Saturn's moon Enceladus. The tiger stripes are fissures that spray icy particles, water vapor and organic compounds. More than 30 individual jets of different sizes can be seen in this image and more than 20 of them had not been identified before. At least one jet spouting prominently in previous images now appears less powerful. Credit: NASA/JPL/SSI. I keep thinking about Project Orion, back in the crazy days before the Test Ban Treaty of 1963...

The Stardust spacecraft recently completed a course adjustment maneuver as it continues on its way to comet Tempel 1. The burn began at 2221 UTC on February 17 and lasted 22 minutes and 53 seconds. The net result: A change of the spacecraft's speed by 24 meters per second. That may not sound like much, but it has big ramifications for this interesting mission. Tempel 1 is a rotating object, and mission scientists want to have a look at places previously imaged by the Deep Impact mission of 2005 (and yes, this is the first time we've revisited a comet). An adjustment to Stardust's encounter time of eight hours and 20 minutes should maximize the chances of seeing the right surface features on the 2.99-kilometer wide potato-shaped mass. The burn took place almost exactly a year before the spacecraft will reach Tempel 1. You may remember Stardust as the first spacecraft to collect cometary samples and return them to Earth for study. After the sample return capsule was retrieved in 2006,...