The planet we live on, our entire solar system, our galaxy, and all neighboring Milky Way Galaxies may reside inside a massive, “empty” cosmic bubble.
We’ve tried understanding our place in the cosmos since time immemorial. Now, as human civilization has reached technological heights of unseen proportions, we are able to try measuring the universe, our galaxy, and immediate cosmic neighborhood, hoping to understand our place in the cosmos.
However, the journey to do so has not been easy, mostly because the more answers we seem to obtain, the more questions arise.
This is the case with the attempted measurements of how fast our universe is expanding. Scientists attempting to measure the speed the cosmos is expanding have run into certain contradictions, and estimates differ greatly.
Now, a Swiss physicist called Lucas Lombriser may have an answer for at least one cosmic dilemma: why do we run into so many contradictions when we attempt to measure the speed by which the universe expands?
To understand the limitations that are present, Lombriser argues that we may actually live within a supermassive cosmic bubble, that encompasses several galaxy clusters close to ours.
The bubble we live in
In a new study published in Physics Letters B, the researcher speaks of an “underdense” region (of low density) that extends a maximum distance of 40 million parsecs (approximately 125 million light-years) from our planet.
The same galactic density values as within the next 10 million parsecs are recorded at X-rays at this height and range from 0.56 to 0.71 with respect to the “Hubble constant.”
In this way, Lombriser’s idea calls into question the expansion rate calculated decades ago by astronomer Edwin Hubble based on the redshift of dozens of galaxies.
However, the Swiss author stated in a letter that it is not necessary to invent a new physics to explain the discrepancies between the two values obtained.
The difference could come from an overestimation of how dense our corner of the universe is, believes Lombriser, who is a professor of Theoretical Physics at the University of Geneva.
“We know that the universe nearby is highly inhomogeneous,” Lombriser explained in an email to Vice.
These variations in density can also occur on much larger scales, something that is consistent with standard cosmological theory.
According to Lombriser, we may live within a very empty region of space that comprises a region along a radius of around 40 megaparsecs (roughly 125 million light-years) or a total diameter of 250 million light-years.
“Such regions are relatively frequent in the cosmos in the standard cosmological theory,” the Swiss physicist explained.
Measuring the speed by which the universe is expanding is a tough thing to do. Astronomers have attempted calculating the distances to supernovae to estimate how fast the universe is expanding, but the numbers obtained may be somewhat distorted by the wrong estimate of the amount of matter in our cosmic neighborhood.
For his part, Lombriser hopes that novel areas of science, such as gravitational wave astronomy (which measures waves in the fabric of space-time), will help solve the problem, heling us answer more longstanding questions about the universe we live in.