Invisible walls in space could help explain how galaxies arrange themselves

Scientists have proposed a new type of physics.
Loukia Papadopoulos
Spiral Galaxy Milky Way.alex-mit/iStock

The universe is a varied and complex entity full of unknowns. To date, astrophysicists' observations about the mapping of the cosmos indicate that small galaxies could be distributed around their host galaxies in random order. 

New data, however, is revealing that these smaller galaxies form thin disks around their hosts, according to a Vice report published on Tuesday. Needless to say, this is confusing as it goes against what previous models of physics dictate.

A new type of astrophysics

To make sense of this new information, two researchers from the University of Nottingham put forth an interesting theory. They speculate that smaller galaxies may be adapting to invisible “walls” created by a new class of particles called symmetrons.

If this turns out to be true, it could rewrite the laws of astrophysics introducing a new type of physics.

The current standard theory, called the Lambda cold dark matter (Lambda-CDM), leaves space for only three key elements to exist in the universe: the cosmological constant, cold dark matter, and the conventional matter we are privy to on a daily basis. This would mean that smaller galaxies would be subjected to the gravitational pull of larger host galaxies and therefore travel in chaotic orbits, a factor that has not been proven thus far by research.

Now, the researchers have conceived of a theory that would explain the unusual orbits of smaller galaxies that pertains to an elusive fifth force.

The creation of invisible walls

This never-before-witnessed force could be responsible for the arrangement of galaxies into disk shapes while particles known as symmetrons could be using this same space to create “domain walls,” types of invisible walls in space.

“We know that we need new particles because we have dark matter and dark energy and so we suspect that we’re going to need to add new particles to our standard model to account for those things,” Aneesh Naik, a research fellow at the University of Nottingham, and lead author of the study told Vice.

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Could Naik's theory prove to be true? Much work needs to be done before it can be considered conclusive but it does open the door to some interesting theories.

The yet-to-be-peer-reviewed study has been published in Cornell University's database.

The observed `planes of satellites' around the Milky Way and other nearby galaxies are notoriously difficult to explain under the ΛCDM paradigm. Here, we propose an alternative solution: domain walls arising in theories with symmetry-breaking scalar fields coupled to matter. Because of the matter coupling, satellite galaxies experience fifth forces as they pass through domain walls, leading to a subset of satellites with orbits confined to the domain wall plane. We demonstrate this effect using simple simulations of a toy model comprising point-like satellites and an infinite domain wall, and explore the efficacy of various planarity metrics in detecting this effect. We believe this is the first potential `new physics' explanation for the observed planes of satellites which does not do away with dark matter.