Our Milky Way Galaxy Is Rippling And The Reason Is Surprising

Photo Credit: NASA

Milky Way, one of the 125 billion galaxies in the observable universe, where our solar system lives, is rippling like a pond disrupted by a stone. At least that’s what scientists want us to believe. In this case, the rock that’s causing the disruption is the neighboring Sagittarius dwarf galaxy, which is equivalent to the size of 400 million Suns, according to Live Science.

But earthlings shouldn’t worry as this hurtling won’t have any effect on them. A new study published in the journal of the Royal Astronomical Society explains that this ancient wobbling will allow astronomers to understand Milky Way’s chaotic past life and how it evolved.

Chaotic Cosmic Dance That Takes Eons To Calm

Scientists also suspect that such rippling might have happened several times in the past as well. The study explains how the Sagittarius dwarf galaxy crashed into the Milky Way eons ago.

Whatever is being observed right now could be a result of age-old cosmic impacts that made stars throughout the galaxy oscillate at different speeds without any reason. Frequent waves of energy ripples across the Milky Way’s surface that jostled the stars take eons to calm down. But how did scientists find out the rippling if we cannot see or feel it?

ESA Gaia Data Used To Draw Conclusions

To observe the wobbling of the galaxy, a team comprising international scientists took the help of the data collected by the European Space Agency's Gaia space observatory. They studied the movements of more than 20 million stars in our galaxy and compared their whereabouts.

The team used a process called “galactic seismology,” which helped them model the ripples as well as the time the Sagittarius dwarf galaxy might have collided with the Milky Way, which they conclude happened hundreds of millions of years ago.

"We can see that these stars wobble and move up and down at different speeds," said co-author of the study Paul McMillan, who is also an astronomer at Sweden's Lund University.

Is Milky Way On Another Collision Coarse?

While other studies done in the past have also concluded that the Milky Way galaxy is rippling, none have managed to show that the effects are seen to its furthest reaches -- suggesting that the dwarf galaxy was actually much bigger than what it might be today.

The latest study also aligns with the hypothesis that our galaxy has crashed into the Sagittarius galaxy on multiple occasions. The study also opens doors for astronomers to study the chaotic history of our galaxy and the likelihood of a similar event in the future.