A Non-empty Bouncing Milne Model
for the Universe
Moncy V. John
Abstract In the late 1990s, a paradigm shift occurred in cosmology when observations of Type Ia supernovae indicated that our universe is undergoing an accelerated
expansion at present and that this is possibly due to the presence of some otherwise unknown, mysterious ‘dark energy’, in addition to ordinary matter and the
already speculated ‘dark matter’. Just before that, a theoretical model of the universe published by the present author and Prof. K. Babu Joseph predicted a universe
expanding linearly (Milne-type coasting evolution), which had a bounce from an
earlier contracting epoch. It suggested the presence of dark matter and dark energy
in the universe, though with densities different from that estimated by the supernova
search teams. It also suggested the possibility that matter is continuously being created in the universe at the expense of dark energy. In addition to broadly agreeing
with all major cosmological observations, the model has the advantage that it has no
cosmological problems. The linear coasting model has several interesting follow-ups
in the literature, such as the R h = ct cosmological model which are reviewed. In the
second part of the present paper, I present a complex extension of the classic Milne
model of the universe and show that this can lead to a bouncing non-empty, coasting
cosmological model as in the case of the above coasting model. In the new model,
the universe had a previous contracting phase and it emerged to the present coasting
expansion phase after a bounce that occurred during a very small time of the order
of Planck time. The present model has the advantage that the space-time attains the
usual Lorentzian signature for the metric tensor after the Planck epoch, though at the
minimum radius corresponding to the bounce, the signature is Euclidean.
Keywords Physical cosmology · Coasting models · Quantum cosmology
M. V. John (B)
School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala, India
Department of Physics, St. Thomas College, Kozhencherry, Kerala, India
e-mail: moncyjohn@yahoo.co.in
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
K. S. Sreelatha and V. Jacob (eds.), Modern Perspectives in Theoretical Physics,
https://doi.org/10.1007/978-981-15-9313-0_1
3
for the Universe
Moncy V. John
Abstract In the late 1990s, a paradigm shift occurred in cosmology when observations of Type Ia supernovae indicated that our universe is undergoing an accelerated
expansion at present and that this is possibly due to the presence of some otherwise unknown, mysterious ‘dark energy’, in addition to ordinary matter and the
already speculated ‘dark matter’. Just before that, a theoretical model of the universe published by the present author and Prof. K. Babu Joseph predicted a universe
expanding linearly (Milne-type coasting evolution), which had a bounce from an
earlier contracting epoch. It suggested the presence of dark matter and dark energy
in the universe, though with densities different from that estimated by the supernova
search teams. It also suggested the possibility that matter is continuously being created in the universe at the expense of dark energy. In addition to broadly agreeing
with all major cosmological observations, the model has the advantage that it has no
cosmological problems. The linear coasting model has several interesting follow-ups
in the literature, such as the R h = ct cosmological model which are reviewed. In the
second part of the present paper, I present a complex extension of the classic Milne
model of the universe and show that this can lead to a bouncing non-empty, coasting
cosmological model as in the case of the above coasting model. In the new model,
the universe had a previous contracting phase and it emerged to the present coasting
expansion phase after a bounce that occurred during a very small time of the order
of Planck time. The present model has the advantage that the space-time attains the
usual Lorentzian signature for the metric tensor after the Planck epoch, though at the
minimum radius corresponding to the bounce, the signature is Euclidean.
Keywords Physical cosmology · Coasting models · Quantum cosmology
M. V. John (B)
School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala, India
Department of Physics, St. Thomas College, Kozhencherry, Kerala, India
e-mail: moncyjohn@yahoo.co.in
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
K. S. Sreelatha and V. Jacob (eds.), Modern Perspectives in Theoretical Physics,
https://doi.org/10.1007/978-981-15-9313-0_1
3