Complex sentence: We need to once again apply the concept of "negative time" to the "beginning of time and space", because the overwhelming enigma of "zero", in this case "zero time", gives us seemingly insurmountable challenges.
Split into simpler sentences: We need to once again apply the concept of "negative time" to the "beginning of time and space". The overwhelming enigma of "zero", in this case "zero time", gives us seemingly insurmountable challenges.