Although it's currently theoretical, one of the most scientifical conclusions to all of life is that the universe is simply going to freeze, thus killing all life. This is called The Big Freeze theory.
This is a scenario in which the universe becomes too cold to sustain life due to continued expansion and the decay of free energy due to the action of entropy. It could occur if the universe's geometry is either flat or hyperbolic, as either of those would mean that the universe would expand indefinitely eventually reaching absolute zero.
If it is hyperbolic, which is usually pictured as a saddle shape, then the density must be lower than the critical density (which is approximately three hydrogen atoms per cubic meter), which means that the universe isn't heavy enough to collapse under gravity. If our Universe is flat, then the density will be exactly at the critical point, preventing the universe from collapsing as well. If the universe is heavier than the critical point, it will result in a shrinking universe, which leads to another theory, called the Big Crunch.
For the Big Crunch to occur, the shape of the Universe would have to be spherical. The problem with measuring the current density of our Universe is that we cannot see most of the matter in it, and it is theorized that most of the universe may be made up of dark matter, a hypothetical, invisible form of matter in space (Which is theorized to be why the night sky is dark).
This is only one of multiple theory's as to the ultimate fate of the universe. If it where to happen, it would probably happen around 150 billion years from now. As of note, our Universe is roughly estimated at just around 13.7 Billion years old.
