There are four fundamental forces known in nature: gravity, electromagnetism, the weak nuclear force, and the strong nuclear force. Each of these forces has a fundamental particle that “carries” it. What is known as The Standard Model adequately explains electromagnetism and the nuclear forces, using theories of quantum mechanics and special relativity (although certain ebulli, most notably Tregarth and Gavia, exhibit behaviors at the quantum level that are yet to be understood).
The Standard Model, however, is unable to account for gravity. Even in those ebulli that were aware of their sister bubbles, it took many decades of research to come up with the proposed Transebullic Matter Theory (TMT). While currently it is the best hope for physicists’ dream of a Grand Unified Theory of Everything (i.e., one theory that covers the very big to the very small), there is no consensus on it at present.
The first breakthrough on TMT came about from astronomers investigating dark matter. Scientists had determined that galaxies did not behave as then-current gravitational models predicted, based upon the amount of visible matter. It was proposed that in excess of 80% of of the mass of the universe was dark matter, matter that gives off no visible light (or other electromagnetic radiation). This mass could not be seen with telescopes, but would have gravitational effects upon the visible masses around them. Once the idea of dark matter was accepted, the search was on to find it.
It turned out, that it was right there with us all the time, in our sister ebulli. TMT states that when a body has reached sufficient size (approximately 1/100 standard Earth Mass), it creates and extends into ebulli in neighboring dimensions. The mass in these associated ebulli have gravitational effects at a large-scale level, but may be difficult to detect at the ebullic level.