Large portions of the Milky Way's outer disc vibrate, according to study conducted by a team led by scientists at Sweden's Lund University using data from the Gaia space telescope.
The dwarf galaxy that shook our galaxy as it passed by hundreds of millions of years ago is to blame for the ripples; it can now be seen in the constellation Sagittarius.
The Milky Way, our cosmic home, has between 100 and 400 billion stars.
The galaxy is thought to have formed 13.6 billion years ago, originating from a revolving cloud of hydrogen and helium-containing gas.
The research team discusses its results regarding the stars in the outer parts of the galactic disc in a new research that was published in Royal Astronomical Society.
These stars can be seen to sway and move upwards and downwards at various velocities.
A little like when a stone is tossed into a pond, our galaxy experiences wave motions as the dwarf galaxy Sagittarius passes by the Milky Way.
The study's principal investigator, Paul McMillan, an astronomy researcher at Lund Observatory, explains.
The study team was able to explore a far broader portion of the Milky Way's disc than was previously feasible because to data from the European satellite observatory Gaia.
The astronomers have started to put together a complicated picture by measuring the strength of the ripples in various regions of the disc.