The Milky Way galaxy seems to be under the effects of near collision like an incident that took place sometime in the past 300-900 million years and as a result, millions of stars were set in motion like that of ripples in a pond, the European Space Agency (ESA) has said.
As per the analysis of the motions of about six million stars present in the Milky Way disc, which forms a major component of our Galaxy, done by ESA’s star-mapping mission Gaia, revealed an interesting and totally unexpected pattern.
One of those shapes was a snail shell-like pattern in the graph that plotted the altitude of the stars above or below the plane of the Galaxy in the same direction but against their velocity.
“At the beginning, the features were very weird to us,” said lead researcher Teresa Antoja from the Universitat de Barcelona in Spain.
“I was a bit shocked and I thought there could be a problem with the data because the shapes are so clear,” she added.
The study, which appeared in the journal Nature, the team along with its chief Antoja investigated to find out what had hit the Milky Way to cause this kind of behavior in the stars.
During their investigation, they were able to find that the unexpected rippling movements of stars in the Milky Way took place when the Sagittarius dwarf galaxy sailed past it between 300 and 900 million years ago.
There are a few tens of millions of stars in this small galaxy and as of now is in the process of being cannibalized by the Milky Way.
Antoja said that its gravity, when passes closely by our Galaxy, would have perturbed some of the stars in our Galaxy, exactly like a stone dropping into the water.
Gaia was designed primarily to investigate the origin, evolution, and structure of the Milky Way and is one of ESA’s cornerstone missions.
By using a combination of their position in the space and their velocity, Gaia measures a three-dimensional movement of stars.
The Milky Way galaxy contains our Solar System. If seen from the Earth, Milky Way appears to be a band due to its disk-shaped structure as viewed from within. Until the start of 20th century, most astronomers considered that the Milky Way was a cluster of stars present in the Universe.
But when the research was done, it was found that it was one of some 100 billion galaxies in the whole universe.
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