“Surprise” or “puzzling” are the most common words in news reports about bodies in the solar system. Here are recent examples that discuss the inner planets.
Mercury: too many volcanoes: A press release from Brown University says the planet Mercury goes against expectations. Mercury has an “abnormally large iron core,” but the evidence for extensive and ongoing volcanism ruins an earlier model that its outer layers had been stripped off. That would also have stripped off its volatile elements. Although it was “long thought” to be depleted in volatiles, new findings show Mercury had plenty, and “held on to them for longer than scientists had expected” —
The surface of Mercury crackled with volcanic explosions for extended periods of the planet’s history, according to a new analysis led by researchers at Brown University. The findings are surprising considering Mercury wasn’t supposed to have explosive volcanism in the first place, and they could have implications for understanding how Mercury formed.
Venus: too few moons (0): Venus is the only large inner planet without a moon. Elisabeth Howell says this on Universe Today: “Considering the amount of stuff flying around the Solar System early in its history, it’s quite surprising to some astronomers that Venus does not have a moon today.” Rescuing Venus from theory, she suggests astronomer’s favorite answer to every solar system anomaly: impacts. “Venus could have been smacked by a large rock at least twice.” When that answer doesn’t work, there’s always the catch-all hypothesis: “There could be other explanations as well, however,” she says.
Venus: possible active volcanoes: Space.com says that there is tentative evidence volcanoes are active on Venus today. A scientist from Max Planck Institute says this could have “major implications” for understanding the planet’s interior, surface and atmosphere.
Moon: hot flashes: Scientists are finding quite a few bright flashes on the moon revealing ongoing impacts, New Scientist reports. Some 300 impacts have been seen since 2006, caused by objects ranging in size from a golf ball to a bowling ball. These impacts send out debris at shotgun speeds – a factor that could endanger future astronaut bases. One bright flash on March 13, 2013 sent debris at 200 miles per second out 18 miles from the main crater, that measures 60 feet across.
Moon: an appetite for apatite: Basalt crystals called apatites provide clues about the water content of volcanic material. Astronomers were discouraged to find that lunar apatites showed similar water content to those on Earth. This damages the popular theory that an impact on Earth formed the moon, because it was expected no volatiles would survive as the moon coalesced. Science Magazine published a new model that preserves those volatiles from “The Lunar Apatite Paradox,” but this is damage control, according to Mahesh Anand’s Perspective piece: “The paradigm of a ‘dry Moon’ was recently challenged on the basis of reexamination of lunar samples collected during the Apollo missions, raising the possibility of a volatile-rich lunar interior.” The latest theory-rescuing model is only one possibility to explain the “dramatic change in our understanding of lunar volatiles” that has arisen in the past decade.
Mars: water wishing: Wet-Marsers have wished for evidence of extensive water on the red planet for decades, so that they could sustain hopes that life might be found there. Nature News says now, though, that the atmosphere has likely been too thin over the planet’s history to allow for much water. Mars may have gotten warm enough for water only intermittently. How? Impacts to the rescue: “a 200-kilometre-wide object slamming into Mars would boost air pressure enough to keep the planet above freezing for around a century,” Sid Perkins ends the article. That’s a little too short a period for life to evolve.
Mars: flood geology: The evidence for cold temperatures flies in the face of another article, posted on Live Science, that gives geological evidence that some canyons on Mars were formed by megafloods. That certainly would have required extensive water. The resemblance of some of these Martian canyons to ones in Idaho that are now interpreted as having formed by large floods (12/19/13) is striking. One canyon photographed recently, Echus Chasma, has the same amphitheater-shaped heads as Stubby Canyon in Idaho. It also contains clays that presumably only could have formed in water. Maybe floods hit Mars within the short periods of heating after large impacts.
Asteroids: disappearing act: A press release from Southwest Research Instituteexplains the fine dust, or regolith, on asteroids coming from “thermal fatigue” or “thermal fragmentation” – i.e., heating and cooling cycles as the body rotates cause microcracks to form in surface rocks, breaking them down relatively quickly. This explanation disputes the former notion that micrometeoroids are the source of the fine regolith dust found on Eros and other asteroids, because the impact debris would reach escape velocity. It means, though, that asteroids could disappear in much less time than the assumed age of the solar system. While the effect is greater on asteroids closer to the sun, “The results of this study suggest that thermal fragmentation, combined with solar radiation pressures that sweep away surface particles, could completely erode small asteroids at distances closer to the Sun (about 28 million miles) in about 2 million years.” That’s 4/100 of one percent of the solar system’s assumed age of 4.5 billion years.
Heather A. Viles discussed these findings about the paper published in Nature, whose authors state that either process (micrometeoroids or thermal fatigue) can rapidly erode near-Earth asteroids in a few million years. On the moon as well, this process may predominate for regolith formation. The model could be applied even to planets with atmospheres, like Earth and Mars. Main-belt asteroids may take ten times longer to break down, but that’s still just 4/10 of one percent of the assumed age of the solar system. Viles states, “Their micromechanical model simulates the measured growth of cracks and shows how growth from an initial crack 30 micrometres in length leads to rapid breakdown of centimetre-sized boulders and the production of finer-grained particulate material.” The authors experimented on rocks undergoing similar thermal cycles and found cracks forming. “Their work has obvious ramifications for developing the study of the geomorphology of asteroid surfaces,” Viles adds. “Diurnal temperature cycling has previously been neglected as a potential contributor to surface modification and regolith production on asteroids.”
Once again, we need to emphasize that while we respect and honor the observational abilities and mathematical prowess of solar system astronomers, there’s a difference between observation and understanding. Secular astronomers are determined to force every observation into a 4.5-billion-year timeframe involving only physical processes – no intelligence allowed. When they keep banging their heads against reality, though, what should bystanders think? Why not use their brains for something more workable, like the possibility that Earth and the planets were created more recently? Why stick to timeframes that contradict their own models? Answer: Darwin needs the time.
This report will continue with an entry on the outer planets, then with a look at current theories for planet formation.