In this paper it is shown that in Brans-Dicke (BD) theory, if one considers a non-minimal coupling between the matter and scalar field, it can give rise to a bouncing universe (i.e. an expanding universe preceded by a contracting universe). Two examples of such universes have been considered in a spatially flat FRW universe and their physical properties have been studied.

The first theoretical evidence for the Big Bang came from Alexander Friedmann in 1922, when he showed that Albert Einstein’s theory of general relativity predicted that the universe was either expanding or contracting. Einstein was so upset with this result that he introduced a cosmological constant into his theory which would make the universe static. Later he said that this was his biggest bl...

We have studied the time dependence of ω for an expanding universe in the generalised B-D theory and have obtained its explicit dependence on the nature of matter contained in the universe in different era.Lastly, we discuss how the observed accelerated expansion of the present universe can be accomodated in the formalism.

Wewanttofindthecosmologicalconstantinfluenceoncosmicmicrowavebackground(CMB)temperatureduetomovinglinearcosmicstrings.Usingthespace-timemetricofalinearcosmicstringinanacceleratedexpandinguniverse,theGott-Kaiser Stebbins(GKS)effect,asanimportantmechanisminproducingtemperaturediscontinuityinthe(CMB),isconsidered;then,itsmodificationduetotheeffectofthecosmologicalconstantiscalculated.Theresultshowsthat...