Simon Lock and Sarah Stewart are intent upon revising our views on how the Moon was formed. Lock is a Harvard graduate student who last year, in company with Stewart (UC-Davis) presented interesting work on what the duo are calling a ‘synestia,’ which is the kind of ‘structure’ resulting from the collision of huge objects. Current thinking about the Moon is that it formed following the collision of a Mars-sized object with the Earth, two huge objects indeed.
What Lock and Stewart asked is whether this formation scenario can produce the result we see today. What it calls for is the ejection of material that forms into a disk and, through processes of accretion, gradually becomes the Moon. The problem with it, says Lock, is that it’s a very hard trick to pull off:
“Getting enough mass into orbit in the canonical scenario is actually very difficult, and there’s a very narrow range of collisions that might be able to do it. There’s only a couple-of-degree window of impact angles and a very narrow range of sizes … and even then some impacts still don’t work.”
Perhaps we’ve misunderstood the original, massive collision. An adjusted formation scenario could explain why ...