An international team of astronomers has discovered a mysterious magnetic ‘bridge’ linking our two nearest neighboring galaxies, the Large and Small Magellanic Clouds (LMC and SMC) which are each close to 200,000 light-years away from Earth. The magnetic bridge stretches for over 75,000 light-years between the two galaxies and is roughly one millionth of the strength of Earth’s magnetic field.
Astronomers discovered the field, known as the Magellanic Bridge, by examining distant radio signals which switched polarity when passing between the LMC and SMC galaxies. This effect, known as Faraday rotation, happens whenever radio waves pass through a magnetic field. While such fields have long been speculated, this is the first direct observation of one. The researchers’ findings have been published in the open-source journal arXiv.org.
In a press release, lead author Jane Kaczmarek from the University of Sydney states that these magnetic ‘bridges’ remain a relatively unknown astrophysical phenomenon that might help scientists understand the origins of the universe itself:
There were hints that this magnetic field might exist, but no one had observed it until now. In general, we don’t know how such vast magnetic fields are generated, nor how these large-scale magnetic fields affect galaxy formation and evolution. Understanding the role that magnetic fields play in the evolution of galaxies and their environment is a fundamental question in astronomy that remains to be answered.
The researchers speculate that such magnetic bridges might form from the leftovers of smaller galaxies as they are absorbed by larger ones, but this is still a hypothesis. Magnetic fields and magnetism throughout the universe remain somewhat of a mystery even though magnetic fields are ubiquitous in space. These fields can only be detected through their interactions with other matter or energy, making them difficult to discover.