Dark energy in its simplest formulation takes the form of the cosmological constant term in Einstein field equations of general relativity, but its composition and mechanism are unknown and, more generally, the details of its equation of state and relationship with the Standard Model of particle physics continue to be investigated both through observation and theoretically.
Most Scientists agree that there was a Big Bang that got everything going in all that we have seen thus far in The Universe. But Dark Matter is one strange little item that we still cannot quite get our minds wrapped around. Where does it fall in place exactly? And people are now pondering if there was a 2nd Big Bang that took place like maybe a repercussion after the 1st. Or even a boomerang effect. But only Dark Matter could have caused the many Questions that still remain such as Where did all the water on Mars go? Sound Strange? Both are so much as we learn more information of Dark Matter.
There are still many questions that we have about the Universe. No one has all the answers. But all of us will see many answers coming out all the time.