Al Jackson reminds me in a morning email that today is the 100th anniversary of the Arthur Eddington expedition that demonstrated the validity of Einstein’s General Relativity. The bending of starlight could be observed by looking at the apparent position of stars in the vicinity of the Sun during a solar eclipse. Eddington’s team made the requisite observations at Principe, off the west coast of Africa, and the famous New York Times headline would result: “Lights All Askew in the Heavens . . . Einstein Theory Triumphs.” Al also sent along a copy of the original paper in Philosophical Transactions of the Royal Society of London, where authorship is given as "F. W. Dyson, A. S. Eddington and C. Davidson." This created an agreeable whimsy: I imagined the evidently ageless Freeman Dyson continually traveling through time to provide his insights at major achievements like this, but the reality is that this Dyson was Frank Dyson, then Britain’s Astronomer Royal. Ron Cowen does a wonderful...

An ocean inside Pluto would have implications for many frozen moons and dwarf planets, not to mention exoplanets where conditions at the surface are, like Pluto, inimical to life as we know it. But while a Plutonian ocean has received considerable study (see, for example, Francis Nimmo's work as discussed in Pluto: Sputnik Planitia Gives Credence to Possible Ocean), working out the mechanisms for liquid ocean survival over these timeframes and conditions has proven challenging. A new paper now suggests a possible path. Shunichi Kamata of Hokkaido University led the research, which includes contributions from the Tokyo Institute of Technology, Tokushima University, Osaka University, Kobe University, and the University of California, Santa Cruz. At play are computer simulations, reported in Nature Geosciences, that offer evidence for the potential role of gas hydrates (gas clathrates) in keeping a subsurface ocean from freezing. At the center of the work, as in so much recently written...

Another reminder that the days of the lone scientist making breakthroughs in his or her solitary lab are today counterbalanced by the vast team effort required for many experiments to continue. Thus the armies involved in gravitational wave astronomy, and the demands for big money and large populations of researchers at our particle accelerators. So, too, with space exploration, as the arrival of early results from New Horizons in the journals is making clear. We now have a paper on our mission to Pluto/Charon and the Kuiper Belt that bears the stamp of more than 200 co-authors, representing 40 institutions. How could it be otherwise if we are to credit the many team members who played a role? As the New Horizons site notes: "[Mission principal investigator Alan] Stern's paper includes authors from the science, spacecraft, operations, mission design, management and communications teams, as well as collaborators, such as contributing scientist and stereo imaging specialist (and...

Few destinations in the Solar System have excited the imagination as much as Europa. Could a deep ocean beneath the ice support a biosphere utterly unlike our own? If so, we could be looking at a second emergence of life unrelated to anything on Earth, with implications for the likelihood of life throughout the cosmos. But so much depends on what happens as Europa's surface and ocean interact. Alex Tolley, a fixture here on Centauri Dreams, today looks at new work suggesting the deeply problematic nature of Europa's ocean from the standpoint of astrobiology. He also offers an entertaining glimpse at what Europa might become. by Alex Tolley Image: Plume on Europa's Surface. Credit: NASA With the abundance of newly discovered exoplanets, a fraction of them being both rocky and in their habitable zones (HZ), the excitement at finding life on such worlds is increasing. Given the ambiguous results of the attempt to detect life on Mars with the Viking experiments in 1976 and the subsequent...

I rarely get the chance to talk about the exotic dwarf planet Haumea, but it’s a personal favorite when it comes to the outer Solar System. That’s because of its odd shape (a bit like an American football), evidently the result of a catastrophic collision, which makes it an interesting object for close study if we can get a probe to it to examine its composition. Back in 2009, Joel Poncy and colleagues at Thales Alenia Space in France went to work on a fast orbiter mission, an extraordinarily tough challenge that would push our propulsion technologies hard. But Haumea would surely repay close study. A rapid rotator (3.9 hours, itself a likely indicator of a turbulent past), it’s a dwarf world with a ring as well as two moons, the larger of which, Hi’iaka, is some 300 kilometers in diameter. Add to this the fact that Haumea is quite reflective, indicating a surface covered with crystalline water ice. We know we can get a probe to Haumea, but orbiting it is an order of magnitude...

What an interesting thing Titan's atmosphere turns out to be. A fine haze produced by sunlight breaking apart methane molecules settles continuously to the surface, leaving organic liquid and solid sediments. Titan also has large lakes, but these contain about a third of the necessary methane, available through evaporation, to replenish that atmosphere, which should be depleted over geological time scales. What produces Titan's supply of methane? It was to answer that question that Caitlin Griffith (University of Arizona Lunar and Planetary Laboratory) and colleagues embarked on a study of cryovolcano activity on Titan. Cryovolcanoes erupt not with molten rock but volatiles like water or methane, and thus could provide an answer if they are venting methane found in subsurface reservoirs. A feature on Titan's surface called Sotra shows cryovolcanic features that imply past icy flows. Image: A giant of a moon appears before a giant of a planet. Titan, Saturn's largest moon, measures...