I love the philosophical method of a “gedanken experiment’ which is A thought experiment whereby a hypothetical situation in which a
The smallest particle is a vibrating, one dimensional string. It size is incredible small but it cannot be zero. (Could it possibly be the Planck constant of 6.55x 10 ^-34 m?} Its vibration is the temperature. The lowest vibration is very close to minus 273.15 degrees Celsius (zero degrees Kelvin}, but can also not be zero and if there is an upper limit it is incredibly high. Since vibration takes time, we have now the 4 dimensions. The single particle dimension, the two vibrational dimensions which together create space and the time dimension, because vibrating takes time. Since negative vibrating is not possible in reality, but only in mathematics, it explains why time is one-directional and not reversible.
The three dimensions needed for the vibrating one dimensional string we call Space. For very high vibration (high temperature) we need very little space for one vibration cycle. For a very low ones we need a lot of space per cycle. Since the Universe is cooling from very high temperature at a minimum size to a cold temperature (entropy?) it must expand and probably does not stop until the temperature is close to minus 273.15 degree Celsius (zero degrees Kelvin) at an enormous size. If the universe is a closed system then the energy is constant throughout the whole process, so the temperature can get very, very low but cannot be zero. Energy cannot be created nor destroyed.
I have to leave it to our smart astronomers, cosmologists and mathematicians to come up with actual experiments to prove or disprove any of the above. Afterall it is their research so far, which gave me the ideas expressed above. Now let me hear from you and what you think.