Satellite Gaia Identified That Milky Way’s Warp Is Due To A Collision With Another Galaxy

Satellite Gaia Identified That Milky Way’s Warp Is Due To A Collision With Another Galaxy
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One of the astronomers’ questions about why is Milky Way warped might get an answer after so many years. Information about ESA’s star-mapping satellite Gaia indicates the distortion might be the cause of a continuous impact with another galaxy.

Such an event would leave ripples through the galactic disc, similar to a rock thrown into the water. Milky Way’s disc is not flat but slightly curved upwards on one edge and downwards on the other. Astronomers knew that fact since the late 1950s.

For decades, they discussed what is causing this warp. Various theories were released, such as the influence of the intergalactic magnetic field, or the influences of a black hole. If such a disc had an unusual shape, its gravitational could change the galactic disc. But things might be a little bit different than that.

Milky Way’s Warp Cause Identified As A Collision With Another Galaxy

The Gaia satellite might have the necessary data for solving this puzzle and answer astronomers’ questions. A team of researchers utilizing information from a second Gaia data release found something quite intriguing. The warp is not static but modifies its orientation sometimes. Scientists dubbed this action phenomenon precession, and it could resemble the wobble of a spinning top as its axis twists.

Also, the velocity at which the phenomenon is performed is speedy than previously believed. For example, it is way faster than the dark matter halo would permit or than the intergalactic magnetic field. That fact indicates that the warp must be a result of something else. Something more steady, such a crash with a different galaxy.

“We measured the speed of the warp by comparing the data with our models. Based on the obtained velocity, the warp would complete one rotation around the center of the Milky Way in 600 to 700 million years,” detailed Eloisa Poggiofrom the Turin Astrophysical Observatory.


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