The two principal abiogenic petroleum hypotheses, the deep gas hypothesis of Thomas Gold and the deep abiotic petroleum hypothesis, have been scientifically reviewed without confirmation. Scientific opinion on the origin of oil and gas is that all natural oil and gas deposits on Earth are fossil fuels and are, therefore, biogenic.
In short a Thru Axle design incorporates a solid rod or hollowed shaft that passes directly through the hub and both legs of the fork or rear frame members. It is then secured to one side of the fork leg or rear frame member (typically on the brake rotor side) by a threaded mechanical connection.
In split-axle designs, the wheel on each side is attached to a separate shaft. Modern passenger cars have split drive axles. In some designs, this allows independent suspension of the left and right wheels, and therefore a smoother ride.n cars and trucks, several senses of the word axle occur in casual usage, referring to the shaft itself, its housing, or simply any transverse pair of wheels.