Summary: The existence of a positive and possibly varying \(\Lambda\) term opens a much wider field of possibilities for the future of our Universe than it was usually thought before. Reliable predictions may be made for finite (though very large) intervals of time only, as well as in other branches of science. In particular, our Universe will continue to expand as far as the \(\Lambda\) term remains positive and does not decay to other forms of matter, even if the Universe is closed. Two new effects due to the presence of a constant \(\Lambda\) term are discussed: a sign reversal of the time change of the redshift for sufficiently close objects and inaccessibility for us of sufficiently distant objects in the Universe. A number of more distant and speculative possibilities for the future evolution of the Universe is listed, including hitting a space-time singularity during an expansion phase. Finally, in the fantastically remote future, a part of our Universe surrounding us can become supercurved and superdense due to various quantum-gravitational effects.
This returns us to the past, to the origin of our Universe from a superdense state about 14 Gy ago. According to the inflationary scenario, this state was almost maximally symmetric (de Sitter- like). Though this scenario seems to be sufficient for explaning the observable properties of the present Universe, and its predictions have been confirmed by observations, the question of the origin of the initial de Sitter (inflationary) state itself remains open. A number of known conjectures regarding the very origin of our Universe, ranging from “creation from nothing” to “creation from anything”, are discussed.