I am not for sure if this helps answer the questions @Agnaa and @Kep..
"But for a Universe filled with dark energy, the story is very different. Dark energy is caused by energy inherent to the fabric of space itself, and as the Universe expands, it's the energy density — the energy-per-unit-volume — that remains constant. As a result, a Universe filled with dark energy will see its expansion rate remain constant, rather than drop at all.
If your Universe is filled with matter or radiation, the expansion rate drops faster than your galaxy's distance increases, so the net recession speed will drop over time: your Universe will be decelerating. If your Universe is dominated by dark energy, however, the net recession speed will increase over time: your Universe is accelerating.
Our Universe, today, is made of approximately 68% dark energy. Starting at around 6 billion years ago, our Universe made the switch to accelerating from decelerating, based on the balance of all the different things within it.
But how is this okay? It seems like a Universe filled with dark energy doesn't conserve energy. If the energy density — energy-per-unit-volume — remains constant, but the volume of the Universe is increasing,
doesn't that mean the total amount of energy in the Universe is increasing? And doesn't that violate the conservation of energy?
This should bother you! After all, we think that energy should be conserved in any and all physical processes that take place in the Universe. Does General Relativity offer a possible violation of energy conservation?
The scary answer is maybe, actually. There are a lot of quantities that General Relativity does an excellent and precise job of defining, and energy is not one of them. In other words, there is no mandate that energy must be conserved from Einstein's equations; global "energy" is not defined by General Relativity at all! In fact, we can make a very general statement about when energy is and isn't conserved. When you have particles interacting in a static background of spacetime, energy is truly conserved. But
when the space through which particles move is changing, the total energy of those particles is not conserved. This is true for photons redshifting in an expanding Universe, and it's true for a Universe dominated by dark energy.
So where does the energy for dark energy come from? It comes from the negative work done on the expansion of the Universe itself. There was
a paper written in 1992 by Carroll, Press, and Turner, which dealt with this exact issue. In it, they state: …the patch does negative work on its surroundings, because it has negative pressure. Assuming the patch expands adiabatically, one may equate this negative work to the increase of mass/energy of the patch. One thereby recovers the correct equation of state for dark energy: P = ― ¤üc2. So the mathematics is consistent. " [
https://www.forbes.com/sites/starts...nergy-for-dark-energy-come-from/#52b61d5d1268 ]
That link goes on further explaining.
but the ratio of dark energy in the universe will need a revision due to the new expansion rate.