More than 2,000 years ago the Hindu yogis of India made a special effort to tune in to, and map, the energies of the 'aura' or 'subtle body'. Since then various, sometimes contradictory, descriptions have come down to us via a number of different routes including 'tantric yoga', 'laya yoga', kundalini yoga' and (relatively recently) 'theosophy'. The apparent contradictions between different traditions surely illustrate that this can be a complex and difficult area to investigate.
The energy of the subtle body is not something that can be seen with the normal eye, and even though yogis began to model it a long time ago, with sensitivities developed through meditative practise, currently science tends not to admit it's existence. As yet such things cannot be measured with the tools of normal scientific research. But. Acupuncture (for instance) works, (even if science can't explain how it works) and acupuncture also deals with the energies of the subtle body. So clearly something is going on!
Clearly the energies of the subtle body are not completely illusory. However, we do need to proceed with caution. Here are some of the problems we face:
Firstly, few of us are strongly clairvoyant, with the ability to percieve subtle body energies directly with some kind of 'inner eye'.
Secondly, because we are not naturally or strongly clairvoyant, few of us are in a position to come to our own conclusions about the veracity of the often-conficting maps of the subtle body that have been handed down, where one tradition says that a certain chakra is red, whilst another says that it is gold, and so on.
The third important point to bear in mind is one that has often been overlooked by Western writers. It concerns the traditional images of the individual chakras, where each one supposedly has a number of 'petals', along with a colour or colours for the central area, and a colour or colours for the petals.
Traditionally, also, a chakra will have been represented as having a certain set of Sanskrit letters inscribed on the petals, along with symbols in the centre such as crescent moons, geometric shapes and so on …
The important point to remember here however is that these images were not meant to be 100% figurative. They were not meant to represent chakras as they would look if only we had sufficient paranormal ability to see for ourselves.