Rearranging Deck Chairs on Sinking Planet Theories
Supernovas come in handy as theory rescue devices.
Fortified iron: Here’s a puzzle: moon rocks have measurable levels of iron-60, Space.com says. But they shouldn’t. Iron-60 has a half-life of 2.6 million years, far too short to have been there billions of years ago when the moon supposedly formed. To keep the moon old, astronomers propose the following auxiliary hypothesis:
Now, scientists have discovered unusually high levels of iron-60 in moon rocks gathered during Apollo missions 12, 15 and 16 between 1969 and 1972. This finding suggests that debris from a nearby supernova sprayed Earth and the rest of the solar system in the past few million years.
Have they thought through the consequences on life if a supernova sprayed the Earth between 1.7 and 2.6 million years ago, when human ancestors were roaming Africa in the evolutionary scheme?
Magnetic magic: One thing we do know is that Earth is better off with its moon. A sun-like star named Kappa Ceti is showing astronomers that a magnetic field is critical for life, Astrobiology Magazine says. Space.com points out that a magnetic field would have been crucial when the Earth formed to keep it from getting sterilized by the superflares that young suns are prone to. Now, PhysOrg adds that the moon–among its many benefits for life—now appears to “play a major role in maintaining Earth’s magnetic field.” Actually, this proposal turns out to be a theory rescue device for another problem:
To maintain this magnetic field until the present day, the classical model required the Earth’s core to have cooled by around 3,000° C over the past 4.3 billion years. Now, a team of researchers from CNRS and Université Blaise Pascal suggests that, on the contrary, its temperature has fallen by only 300° C. The action of the moon, overlooked until now, is thought to have compensated for this difference and kept the geodynamo active.
Blasting gold: Where does gold come from? Science Daily proposes that it comes from supernovas, but “At this time, no one knows the answer.” The puzzle goes for other heavy elements, too. A downstream problem is how it arrived in sufficient quantities on the surface of Earth to cover the tomb of Tutankhamen and other ancient works of art (see 10/20/15 and 3/17/13).
Missing dwarfs: Is it dwarfs or dwarves? Whichever, they’re missing. Science Daily tells about “the missing brown dwarfs” that are too large to be planets but too small to be stars. They should be all over the place, but the sky turned up empty in a search. It’s crisis time again. Planets are supposed to be composed of heavy elements that formed in supernovas. Now, the supernova deficit impinges on a star-formation deficit.
The scientists concluded that there should be many more brown dwarfs in the solar neighbourhood that are yet to be discovered and that will fill the observed gap. If they are right, this would mean that star formation fails significantly more often than previously thought, producing one brown dwarf for every four stars. In any case, it appears, the established picture of the solar neighbourhood and of its brown dwarf population will have to be rethought.
Rearrange the chairs again: The problems reported above are subsumed in a bigger problem reported by New Scientist. The headline, “How two tiny dots defy the history of life and the solar system,” indicates that zircons from Australia’s Jack Hills formation are throwing theories into a tizzy, and along with that, the notions of a Late Heavy Bombardment so trendy in solar system formation models. “When it came to explaining how these things all got started, we thought we had it more or less worked out,” Colin Stuart writes, indicating that prior confidence was unwarranted. “It was a nice story,” he laments. His chart shows how these zircons require scrapping the LHB, moving planetary migration half a billion years earlier, and moving the origin of life 300 million years earlier. But with those corrections, other things stretch and break. How did the Earth cool so fast? How did life get started so quickly? When were the large impact basins on the moon formed? “Future work” will be required to put the new pieces together without breaking something else.
Modern science marches on. Aren’t you glad we have such wise and competent wizards to explain reality? The reality of the 1970s, of course, never was reality to begin with. Today’s reality may be tomorrow’s fiction. There are an infinite number of ways to rearrange the deck chairs, so these adjustments are likely to continue far past our lifetimes. Each generation will be presented with a comforting picture of reality to keep the funding flowing to the scientific wizards. Occasional anomalies are good for this system; it keeps them looking busy. If they ever figured everything out, there would be nothing more to do but keep climbing, until they reach the summit, where the theologians have been sitting for centuries.