Scientists have found that another galaxy is slowly pulling apart with “extreme violence”, the Milky Way, our very own galaxy. It is being twisted and deformed! Using a statistical model, researchers from the University of Edinburgh calculated the speed of Milky Way’s stars and our galactic neighbour.
The Milky Way is being pulled apart at 71,600 miles per hour by the gravitational force of the dark matter halo surrounding the LMC, causing our galaxy to be deformed. LMC stands for Large Magellanic Cloud, which is a satellite galaxy of the Milky Way.
It is visible as a faint cloud in the southern hemisphere’s night skies. Its named after Ferdinand Magellan, a renowned 16th-century Portuguese explorer, who was the first to circumnavigate the Earth.
The discovery inverts the belief that our galaxy is relatively static, resulting in a need for new models that will be required to describe the evolution of the galaxy. It will require researchers to study further and re-evaluate how our galaxy was first formed.
Effects on the Milky Way
Dr Michael Peterson, lead author of the study and his colleagues explained that the LMC intruded into the boundaries of the Milky Way, ‘recently’ – 700 million years ago. Large dark matter surrounds this galaxy, which upset the fabric and motion of our galaxy as it fell in.
Dark matter is a mysterious ‘glue’ which holds galaxies together. We are unable to observe it directly since it doesn’t emit, reflect or absorb light.
Peterson said that the effects of this relatively recent collision are still being witnessed today, and should force a revision of the birth of the Milky Way.
Other findings of the study
Previous research has shown us that the LMC is surrounded by a halo dark matter, similar to the milky way and possibly all galaxies. The study revealed that the large attraction of this dark matter is pulling the Milky Way disc at 71,600 mph, or 20 miles a second.
To the surprise of the researchers, the Milky Way is not moving in the LMC’s current direction, as previously thought. Rather, it is moving away from it in the opposite direction, towards constellation Pegasus in the northern sky.
This can be explained by the fact that the LMC itself is floating away at an even faster speed of 800,000 mph or 830 miles per second. Interestingly, this chase between the two galaxies is linked to our galaxy trying very hard to hit a target, but not aiming well. The discovery will enable scientists to study the dynamics between the two galaxies by developing new modelling techniques.
Dr Petersen said, “We were able to show that stars at incredibly large distances – up to 300,000 light-years away – retain a memory of the Milky Way structure before the LMC fell in, and form a backdrop against which we measured the stellar disc flying through space, pulled by the gravitational force of the LMC.”
The researchers now aim to find out the direction from which the LMC first collided with the Milky Way, and the exact time it took place. It will give a much clearer picture of the amount and distribution of dark matter in the Milky Way and the LMC.
Professor Jorge Penarrubia, co-author of the study said, “This discovery definitely breaks the spell that our galaxy is in some sort of equilibrium state. Actually, the recent infall of the LMC is causing violent perturbations onto the Milky Way. Understanding these may give us an unparalleled view on the distribution of dark matter in both galaxies.”
Last year, researchers from Durham University warned that the LMC will destroy Earth in about 2 billion years (phew!) by re-awakening our galaxy’s dormant black hole. Thank god we would have lived out our days by then!