We have two patches of glass in the desert. One is round, the other is oval-shaped, but has the center gouged out of it. Which is the more likely explanation:
a) Some ancient people developed an advanced civilization, apparently without ever experiencing the worldwide population boom we've experienced, and without leaving any evidence behind whatsoever of any skyscrapers, modern-style roads or other modern-type structures. They developed nuclear weapons, and delivery systems (presumably missiles), yet all of these were somehow destroyed. They fired some kind of nuclear weapon that, by some unknown mechanism, created an oval-shaped glass patch, rather than a round one, and which in addition only created glass in a ring, leaving the center untouched.
Or, b) Sometime during the last million years or so, a somewhat structurally unstable meteor came into the earth's atmosphere at an angle above the desert. Shortly before impact, it split into two pieces. One piece exploded with violent heat very close to the earth, forming an oval glass patch in the desert, except for the center which was gouged out by a fragment. The other piece, perhaps larger, exploded a big higher and thus created an essentially circular patch.
why start now?