The Absolute Cosmos: Large Magellanic Cloud encounter violently disturbed Milky Way
The Large Magellanic Cloud- a satellite galaxy of the Milky Way can be seen as a faint cloud in the night skies of southern hemisphere. A 16th century Portuguese explorer Ferdinand Magellan spotted the galaxy first in 1519- hence the galaxy now bears his name.
It is thought that the Large Magellanic Cloud crossed our galaxy’s boundary about seven hundred million years ago, which according to scientists, is a recent event in cosmological terms.
The gravitational force of The Large Magellanic Cloud (LMC) is pulling, twisting and deforming the spiral shaped disk of stars and planets in our home galaxy Milky Way.
Because of LMC’s large dark matter content it hugely unsettled the Milky Way’s motion and fabric as it fell in and its effects are still being observed today.
In the past, scientists have established that LMC, more like our galaxy Milky Way, is enveloped in a halo of dark matter.
Dark matter doesn’t absorb, emit or reflect light, thus making it highly difficult to detect. Scientists can only infer its existence from the gravitational effects it seems to have on visible matter.
A team of scientists from the University of Edinburgh, used a statistical model to measure the speed of Milky Way’s most distant stars.
They found that towards the Pegasus constellation, gigantic attraction from the Magellanic Cloud’s dark matter halo is twisting and pulling the Milky Way disk at thirty two kilometres per second.
The study also shunned the previously thought idea that Milky Way was moving towards the current location of LMC, instead it was revealed that Milky Way is moving towards a point on its past trajectory.
The team believes that this is due the fact that LMC, because of its massive gravitational force, is moving away from the Milky Way at even faster rate of 370 kilometres per second.
Scientists now plan to work out the direction from which the LMC first fell in to our galaxy and exactly when it happened. This will further help in measuring the distribution and amount of dark matter in the LMC and Milky Way galaxy.
As per team, the stars at extremely large distances (up to 300,000 light years), bears the memory of Milky Way fabric before the LMC fell in and created a backdrop against which scientists measured the stellar disk moving through space pulled by LMC’s gravitational force.
For more information: Detection of the Milky Way reflex motion due to the Large Magellanic Cloud infall.