As the universe started its creation with a big bang nearly about 13.7 billion years ago. The universe consists of trillions of galaxies receding from each other with the expansion of the universe. From the study of general relativity, the universe must have an end. The two possiblities of end depend upon the density of the universe. If the density of the energy and matter is less than a certain value called critical density the universe after expanding for some time will come to contract its initial state. The end is called big crunch and the universe is closed. But if the density of the universe will be greater than the critical density, the universe will be expanding forever untill its temperature comes to freeze. This end is known as big chill and the universe is open. General relativity fails to explain the ultimate end of the universe. Today's mordern theory is the M-theory and i think the only reason to know the end of this universe is known first how universe was created. According to concept of M-theory. The universe came to existance with the collusion of two multidimensional branes (branes are the multidimensional planes). There energy of collusion created the matter and energy of this universe. Understanding this very sensitivily, when the two branes collide with each other it is obvious that after the collusion the branes move apart from each other and allowed this universe to expand freely without any disturbance of their density. Presently, the universe is expanding due to the spreading of the two branes from each other and minimizing the effect of their density on this universe. The decreasing effect of the density of two branes increases the expansion energy of this universe. Physicist called this dark energy. The reason of increasing dark energy is due to spreading of branes from eachother. Now when the two branes can come back again for collusion as it was at the time of big bang when they will come towards each other the effect of their density on this universe as a bubble will slow down its expansion and will make it to contract. The space of this universe will contract with all matter and energy and thus finally when the branes will again collide the universe contracts to zero volume and thats singularity. Thus this makes the universe cyclic. I hope this makes us to understand the ultimate demise of this universe through the study of this new modal from M-theory. Thankyou! Sharik khursheed, Researcher, American physical society.