If the Earth and our galaxy, as well as all the neighboring galaxies, were inside a large bubble, then this would solve a number of questions related to the nature of the Universe.
The universe may seem like a relatively calm and static place. But astronomical observations over the past century have shown that it is expanding with acceleration caused by mysterious forces called dark matter and dark energy. At the same time, scientists cannot agree on their estimates of the rate of expansion of the boundaries of space.
The answer may lie in the fact that we live in the “Hubble bubble” – a giant region of space, with a different density than the rest of the universe. Such a theory was put forward by the theoretical physicist from the University of Geneva, Lucas Lombreiser.
The bubble hypothesis has been around for more than two decades, but the other day, Physics Letters published an article describing the possible size and characteristics of this speculative bubble.
Lombreiser argues that there is no need to invent new physics to explain the discrepancy between the two Hubble constants. The difference may lie in the density of the bubble relative to the average cosmic density of the substance.
“We know the universe is not homogeneous,” explains Lombreiser. “The density of particles in the earth, atmosphere or in the space between the Earth and the Moon, as well as the Sun, is different.”
In his article, Lombreiser suggests that we may be in a relatively empty region that has a radius of 40 megaparsecs (roughly 125 million light years). “Such regions are relatively common in the universe in standard cosmological theory,” Lombreiser argues.
If our bubble contains about half as much matter as the rest of the cosmos, that may explain why we keep getting different results for the Hubble constant.
The bubble idea is just a hypothesis, and to prove it, additional observations will be required, during which it can be determined whether the uneven distribution of matter in the universe can explain the discrepancy between the observed Hubble constants.