Will the universe keep on expanding forever or is there enough gravity to slow down the expansion?

There is more of this unidentified dark energy than there is gravity, and it is much stronger. The only theories regarding the fate of the Universe are as follows: if the number and size of galaxies increase, the density of the Universe (and therefore the gravity) will also increase, slowing down the Universe and potentially leading to its collapse.

The universe will either expand forever, leading to a "Big Freeze" or "Heat Death" scenario, or it will expand at a constant rate, depending on the density and rate of expansion of matter and energy in the universe. If the density is high enough, gravity will eventually slow down the expansion and may even lead to a contraction, resulting in a "Big Crunch." Current observations suggest that dark energy is causing the universe to expand faster, which favors the scenario of eternal expansion. However, research is ongoing to understand the ultimate fate of the universe.