Strange things happen on our nearest neighbor. Stranger things happen in the heads of theorists trying to figure out our nearest neighbor.
The first news item involves legitimate puzzle-solving about a previously-unheralded physical process: lightning in lunar dust. This lightning, explained below, could “garden” the lunar dust as much as meteoroid impacts. NASA explains:
Powerful solar storms can charge up the soil in frigid, permanently shadowed regions near the lunar poles, and may possibly produce “sparks” that could vaporize and melt the soil, perhaps as much as meteoroid impacts, according to NASA-funded research. This alteration may become evident when analyzing future samples from these regions that could hold the key to understanding the history of the moon and solar system.
The moon is, therefore, physically bombarded by things small as well as things large. Planetary scientists have not been unaware, of course, that the moon is continually buffeted by charged particles in the solar wind. What’s new is the realization that permanently-shadowed regions (PSRs) near the poles are not safe spaces. A video in the article shows that starlight casts its own dim light into these shadowed craters—light that the Lunar Reconnaissance Orbiter can measure. Something unusual happens in these cold, dark craters.
In August 2014, however, Jordan’s team published simulation results predicting that strong solar storms would cause the regolith in the moon’s permanently shadowed regions (PSRs) to accumulate charge in these two layers until explosively released, like a miniature lightning strike. The PSRs are so frigid that regolith becomes an extremely poor conductor of electricity. Therefore, during intense solar storms, the regolith is expected to dissipate the build-up of charge too slowly to avoid the destructive effects of a sudden electric discharge, called dielectric breakdown. The research estimates the extent that this process can alter the regolith.
We all experience “dielectric breakdown” when our fingers zap a doorknob after scuffing shoes on a dry carpet. On the warmer parts of the moon, negative electrons from the solar wind travel deeper into the lunar soil than the positive ions, setting up a voltage. The warmer temperatures, however, allow the charges to migrate toward each other and dissipate calmly. The PSRs are so cold, they cannot migrate as fast. The dielectric (i.e., the insulator) of the frigid soil can’t hold the charges apart forever. Eventually, it breaks down, creating an explosive spark on a very tiny scale. The sparking is strong enough, though, to blow dust grains apart, breaking up the lunar soil just as effectively as micrometeoroids do. This same process disrupts spacecraft orbiting the earth. It’s “the leading cause of spacecraft anomalies,” Bill Steigerwald writes.
What this implies is that PSRs have a second cause of lunar soil gardening that goes on continually. Jordan estimates that it would take a million years for micrometeoroids to garden the lunar soil. Now, this second physical process of explosive sparking could produce an equal amount of soil disruption in PSRs, particularly during large solar storms. His team estimates about 10–15% of the soil could be affected this way. For a primer on what static electricity can do, see article on The Conversation.
But does sparking occur only in the PSRs? Maybe not. It’s possible the entire lunar surface could be affected, Jordan says. That’s because the moon experiences very cold temperatures during the two-week-long lunar night. At midnight, even the equatorial regions could get cold enough to feel the micro-lightning process of dielectric breakdown. Over time, this could add up to significant gardening of the regolith (lunar soil). Although more research is needed, Jordan thinks even the Apollo samples might show evidence of this disruptive process. The lunar soil may have more gardeners at work than thought.
The PSRs are important locations on the moon, because they contain clues to the moon’s history, such as the role that easily vaporized material like water has played. But to decipher that history, we need to know in what ways PSRs are not pristine; that is, how they have been weathered by the space environment, including solar storms and meteoroid impacts.”
Another implication of the research involves the lifetime of water deposits in these permanently shadowed regions – not only on the moon, but Mercury, Ceres and other planets and solid bodies in the solar system. No place is really permanently shadowed. Even the darkest crater floors receive radiation from space, which contributes small amounts of thermal energy. Over assumed billions of years, would this radiation disrupt a surface and slowly release its volatiles to space? Further research may answer this question. The fact that scientists were surprised by the amount of “space weathering” going on in these assumed sheltered locations indicates the possibility for impacts of another kind: the sound of sparks as reality zaps theory assumptions.
Lunar Origins: Multiplied Miracles
The leading theory for the origin of the moon – coalescence from debris after Earth was hit by a Mars-size object – is being obliterated by insurmountable problems coming in like death comets. But is the replacement model better? If one impactor hitting at just the right speed and angle amounted to a miracle, how about 20? Space.com tells the new story coming from three scientists at the Weizmann Institute in Israel:
The new, multiple-impact hypothesis suggests that about 20 moon– to Mars-size objects struck the Earth, flinging debris from the planet into orbit. There, the debris formed disks around the Earth that looked somewhat like Saturn’s rings. Over centuries, debris in several disks accreted to form moonlets that migrated farther and farther from the Earth due to tidal interactions. Eventually, the moonlets settled at a distance known as the Hill radius, coalescing to form one big moon.
The new theory, published in Nature Geoscience, was motivated by a serious problem in the old model: “it doesn’t provide a good explanation for the strong similarity between the composition of the moon and the Earth.” The authors indicate why new models are needed, but don’t assess the probability of multiple impactors of the right size hitting the same planet (Earth) in succession.
The hypothesis of lunar origin by a single giant impact can explain some aspects of the Earth–Moon system. However, it is difficult to reconcile giant-impact models with the compositional similarity of the Earth and Moon without violating angular momentum constraints. Furthermore, successful giant-impact scenarios require very specific conditions such that they have a low probability of occurring. Here we present numerical simulations suggesting that the Moon could instead be the product of a succession of a variety of smaller collisions. In this scenario, each collision forms a debris disk around the proto-Earth that then accretes to form a moonlet. The moonlets tidally advance outward, and may coalesce to form the Moon. We find that sub-lunar moonlets are a common result of impacts expected onto the proto-Earth in the early Solar System and find that the planetary rotation is limited by impact angular momentum drain. We conclude that, assuming efficient merger of moonlets, a multiple-impact scenario can account for the formation of the Earth–Moon system with its present properties.
On the surface, this theory appears outrageously more improbable than the previous model. How do so many bodies find the Earth, which from a few astronomical units away, is a mere speck? One impactor too large coming in too rapidly would obliterate the entire Earth before another could contribute its mass to an “Earth-Moon system” possessing any properties at all. And “assuming the efficient merger of moonlets” goes against what is known about accretion of small particles (they bounce; they don’t stick). The Israeli team is working on the accretion problem next.
Will NASA buy this new model? (It’s actually a revival of a “discarded theory,” Phys.org points out in its article titled, “Study crashes main Moon-formation theory.”) Time will tell, but what are they going to say? The old model has two insurmountable problems: probability and angular momentum. Modeling the origin of the moon for the time being, therefore, will continue to be a crapshoot.
Crapshoot: perfect description. Defined as “a risky or uncertain matter,” it also implies that modelers are saying behind closed doors, “Oh, crap!” and flinging their wasted theories out the window like you-know-what. Science reporters, finding the you-know-what on the ground, spray perfume on it and market it to the public as the latest Science Fudge. Now you know the reason behind fudging data in science.
I ask our skeptical readers: Do you see progress here? Are planetary scientists getting warmer? Look at them: reviving a discarded theory! Is this not like a drunken sailor’s walk around the lamppost? Sometimes the sailor’s gotta go, so he deposits Science Fudge for the reporters to pick up. Why not look at the Lamp to find out where the moon came from? Why is that so unthinkable? Look at the situation; all the leading theories are hopelessly improbable. You have to admit the moon looks designed. We all believe in miracles anyway. Why not pick a miracle that is designed for a purpose and fits the observations?
The story about sparking in the lunar soil is worth further study. Non–moyboy physicists might want to take a serious look at the data and see if the observations militate against millions and billions of years, because the Science Fudge emerging from the secular scientist’s A.S.S. (age of the solar system) indicates pathology.