○Dark energy is to expand the space.
☆Two of the nature of the following is assumed.
（１）Repulsive force between the antimatter at the interface of the real universe produces dark energy.
・・・However, it is hard to explain the re-acceleration of the universe expansion by this assumption.
（２）☆Dark energy is considered to be a particle with the structure like dark matter(fine particles having a three-dimensional structure) .
・・・The inflation of the universe can be explained by this assumption.
・・・The re-acceleration of the universe expansion can also be explained.
⇒☆Expansion of the universe is likely to stop in abruptly like an automatic umbrella.
・・・However, if the dark energy is the transition such as in the figure below, it can explain the re-acceleration even not have a structure.