More notes on the ‘wandering planet’ scenario advanced by John Debes (Carnegie Institution of Washington) and Steinn Sigurðsson (Penn State), which suggests that planets ejected from their stars as their solar systems formed could conceivably keep enough internal heat to maintain an atmosphere and sustain a liquid ocean under ice. Debes’ simulations show that a planet with a large moon could survive the ejection process.
Noting that between four and five percent of the simulations the duo ran on an Earth-mass planet with Luna-like companion resulted in the ‘Earth-Moon system surviving, Debes had this to say in an article in Sky & Telescope:
“Anytime something happens in astronomy a few percent of the time, it is interesting to us because on the grand scale of things, it means it’s happening a lot and people should probably know about it.”
Interesting indeed, because a large moon means tidal energies between moon and planet that could cause the interior of the planet to warm. Debes and Sigurðsson think the heating would be localized in hot spots of volcanism or other geothermal processes, making the case for extremophiles like those along Earth’s mid-ocean ridges as a perhaps common form of life in the cosmos. The paper is Debes and Sigurðsson, “The Survival Rate of Ejected Terrestrial Planets with Moons,” Astrophysical Journal 668 (October 20, 2007), L167-L170 (abstract).
The unexpected outburst on Comet 17P/Holmes has made it brighter than any comet in the past decade. Now shining at 2nd or 3rd magnitude, it’s visible all night long at mid-northern latitudes, spanning an apparent diameter of 90 arc-seconds. You can find sky charts for viewing here. Nice to see cometary enthusiasm so intense that, when the Harvard-Smithsonian Center for Astrophysics asked their staff for viewing reports and images, responses poured in despite the competing attraction of the Red Sox in World Series game two. The comet, says one observer: “…looks like a big yellow globular cluster through binoculars. Truly a one of a kind object.” Even more one of a kind would be a Rockies comeback after their hard times at Fenway Park, but hope persists.
Vinton Cerf, now a Google vice president but best known for the invention of the TCP/IP protocols that drive the Internet, told a gathering in Seoul that the InterPlanetary Internet project is on course. According to this AFP story, Cerf expects a key part of the IPN, which would establish broad standards for space communications, to be completed in three years: “This effort is now bearing fruit and is on track to be space qualified and standardized in the 2010 time frame.” Adapting Net protocols to the huge latency problems of deep space missions will result in a robust interplanetary communications infrastructure, one that will maximize the potential of the Deep Space Network as spacecraft collect and pool their data before phoning home.
North Carolina State’s PULSTAR reactor is in the news with the production of the most intense low-energy positron beam operating anywhere. The idea, says NCSU’s Ayman Hawari, is simple: “…if we create this intense beam of antimatter electrons – the complete opposite of the electron, basically – we can then use them in investigating and understanding the new types of materials being used in many applications.” The focus now turns to new intstrumentation such as antimatter spectrometers and microscopes, but propulsion theorists will want to keep a long-term eye on the implications of such work for increasing our ability to produce and deploy antimatter.