Beliefs about crop circles have changed over time:
People used to think it [the crop circle phenomenon] was [caused by] witches and fairies; then it was aliens. Today, people think it might be electro-magnetic pollution, caused by the proliferation of radio masts and mobile phones.
Could they be related to "ancient ley lines?"
It may well be that the earth does have these energy lines, and it may well create some sort of current when these lines intersect with the magnetic fields.
Some scientists believe that crop circles are somehow connected to
sound formations. (The link depicts the geometric
formation found at Silbury Hill in 1997 and compares it to a remarkably similar sound vibration that had been captured on film.) The pioneering efforts of Swiss scientist,
Hans Jenny may help to explain the crop circle phenomenon:
In 1967, Swiss scientist Hans Jenny published the first of his painstaking
studies of the vibrational affects on physical mediums such as water, plaster, oil and sand-cymatics. By transmitting sound in the shape of a monitored frequency through these elements he was able to capture on film the exact geometric pattern that sound makes as its vibrations move through these substances. Changing the vibration altered the shape of the geometry captured in the receiving substance - a low frequency produced a simple circle encompassed by a ring, whereas a higher frequency increased the number of concentric rings around a central circle. As the frequencies rose so too did the complexity of shapes, to the point where tetrahedrons, mandalas and pythagorean forms could be discernible. Jenny not only managed to
solidify sound, he also enabled humanity to observe frozen music.
Did he also, unwittingly, help cereologists understand how naturally occurring crop circles are formed? No one - not even the scientists - can be sure. (Scroll down 50%.)