Eruptions can come in two types: literal and figurative. Some planetary bodies are literally erupting. Others are causing figurative eruptions in theories. Here are some recent news stories about planets, moons, comets and other objects circling our sun and other stars. There hasn’t been much news from Mercury or Venus this month, so we’ll start on the home planet and work outward.
Earth volcanoes: Earth is busting out all over. You can watch the fireworks going on at Mt. Etna on this BBC News video clip. Live Science has a video of the hottest, deepest volcano on earth, found underwater near Fiji. New Scientist resurrected the “heretical” view that the dinosaurs were killed by lava, not a meteor; two giant blobs of mantle that erupted onto the surface. One geologist remarked, “This will be controversial – it flies in the face of much of the research from the last 30 years.” Wynne Perry at Live Science (see MSNBC) entertained the entertaining question, “Did a methane burp clear the way for the dinosaurs?” Over at Science Daily, the idea was presented that much of earth’s surface was formed from ancient flood basalts, “giant lava eruptions that coat large swaths of land or ocean floor” periodically. Incidentally, geologists are not sure where Earth’s internal heat comes from, especially since Japan’s KamLAND antineutrino detector came up short (see Science Daily). “One thing we can say with near certainty is that radioactive decay alone is not enough to account for Earth’s heat energy,” remarked Stuart Freedman of Lawrence Berkeley National Lab. “Whether the rest is primordial heat or comes from some other source is an unanswered question.”
Moon volcanoes: A region of volcanism was found on the back side of the moon. Most of the volcanic evidence, the maria, is on the near side, but in the middle of the cratered regions on the far side, reported PhysOrg, “a small volcanic province created by the upwelling of silicic magma” was reported by remote sensing of chemical clues by the Lunar Prospector. “The unusual location of the province and the surprising composition of the lava that formed it offer tantalizing clues to the Moon’s thermal history.”
Mars volcanoes: A Texas geologist is pouring lava on hopes for life on Mars by resurrecting a “heretical” view that most of Martian history was created by lava, not water. According to PhysOrg, David Leverington (Texas Tech) argues that slippery, low-viscosity lavas mimicked the action of water, carving the channels and basins that so tantalize astrobiologists. “If Leverington is right, the odds of life on Mars plummet to near zero,” because Mars would have been bone dry most of its history. “But that’s a big ‘if’,” the article cautioned. Arguments on both sides of the debate were presented. JPL’s next Mars rover Curiosity, scheduled for launch this fall, has a target for its August 2012 landing: Gale Crater, which is thought to have had liquid water in the past (Live Science). Mission scientists, who love to look for water with visions of life, are probably hoping Leverington is wrong.
Vesta geology: JPL’s DAWN spacecraft arrived in orbit at the giant asteroid Vesta on July 17. It’s too early for science results, but the BBC News posted some of the best early images of the colorful, crater-packed surface.
Jupiter moon mysteries: Live Science posted a review of “The Greatest Mysteries of Jupiter’s Moons” by Adam Hadhazy. He presented the traditional tidal-flexing model of Io’s volcanism, but then admitted that tidal forces alone “might not account for all this oomph.” The Juno spacecraft, readying for its launch in August, may make Io a prime target for study. News media like PhysOrg and the Los Angeles Times have been exaggerating its capabilities as if one mission could “find the recipe for planet-making.”
Titan volcanoes: Out at the Saturn system, the source of Titan’s atmosphere is still a puzzle. New Scientist said that planetologists are still unsure whether material has erupted onto the giant moon’s surface and replenished the methane which otherwise would be gone within 15 million years (a third of 1% the assumed age of the moon). The article by Jeff Hecht reviews the findings and mysteries of this major enigmatic body of the solar system.
Enceladus showers: Saturn is feeling the eruptions from its little geysering moon Enceladus. That surprising announcement came from the news room of the Herschel Space Observatory, a mission of the European Space Agency. “Enceladus rains water onto Saturn,” PhysOrg said; New Scientist headlined, “Moon-showers give Saturn an aquatic belt.” The infrared instrument on the orbiting telescope was able to detect the water and estimate that 5 percent of the eruptive water vapor (250 kg per second) “falls on Saturn where it collects to form a ring extending five times the width of the planet.” This process is “unique to Saturn,” PhysOrg said. The water belt extends out 10 Saturn radii and is one Saturn radius thick. What happens to the other 95 percent? “Although most of the water from Enceladus is lost into space, freezes on the rings or perhaps falls onto Saturn’s other moons, the small fraction that does fall into the planet is sufficient to explain the water observed in its upper atmosphere.”
Pluto moon: The Pluto system has added a child: Hubble discovered another small moon, bringing the family to four moons and a parent “dwarf planet” as Pluto is now labeled (PhysOrg). Space.com quoted Alan Stern, principal investigator of the New Horizons spacecraft slated to swing by Pluto in July 2015. “This is a whole new kind of planet,” he said. “It’s going to blow our doors off.” One door ready to be blown is the dynamical problem of how such a small body could have four objects in orbit around it for billions of years.
Comet eruptions: A “theory eruption” has taken place regarding comets. Sample returns and remote sensing has established that some cometary material formed at high temperatures, contrary to decades of assumptions. PhysOrg presented work by European researchers who came up with a model employing “photophoresis,” that assumes material from the hottest parts of the inner solar system got cooked sunny side up. The difference in temperature on the two sides of a particle leads to migration, they say, conveying the cooked material outward by sunlight pressure, where it became incorporated into comets. “This novel physical explanation could account for the position of certain dust rings observed in protoplanetary disks and thus shed light on the conditions of planet formation,” they said. Whether the model works if the grains rotate was not clear from the article. Comet Hartley 2 is a real-world comet that made the news on PhysOrg. Its tail includes particles as large as golf balls.
Extrasolar planets: Space.com is dabbling in the occult. Its article, “How to keep lonely planets snug: just add dark matter” calls on mysterious unknown stuff to warm up lonely exoplanets wandering through the darkness of space. Neither isolated planets nor dark matter have ever been observed, but the author quoted an astrobiologist who went even further into speculation, imagining life on such worlds subsisting off the internal heat from imaginary dark matter interactions with the imaginary planets.
On his blog The Procrustean, physicist Rob Sheldon told a personal story of his friend’s quest to measure the solar wind. It led to the Genesis mission, which found that the oxygen isotope ratios differ between the solar wind and earth, leading to the conclusion that Laplace, inventor of the nebular hypothesis, was wrong – not only in his physics, but his metaphysics (compared to Newton’s). Tied into the discussion was Cornelius Hunter’s recent philosophical entry on his blog Darwin’s God about Laplace, Kant, Darwin, and god-of-the gaps hypotheses.
We are very fortunate to live in an age of exceptional discoveries in astronomy. We are less fortunate to live in a time of incorrigible materialism, when our science representatives spend reckless drafts on the bank of time to a point where we face an international debt crisis that is unlikely to be paid back, even with higher taxing of credulity.