Milky Way’s Strange Warped Shape Could Be Caused by an Ongoing Collision With Another Galaxy

The Milky Way has a wierd warped form, and scientists now imagine this can be the results of a comparatively latest or ongoing collision with one other galaxy.

While it’s possible you’ll consider the Milky Way as a flat disk, it’s truly formed nearly like an “S.” Its outer edges seem distorted in comparison with the interior flat disk, curving barely upwards at one finish, whereas the opposite finish curves downwards.

The warp is seen within the distribution of stars, mud and fuel within the galaxy. The orientation of this warp—or its “precession” as astronomers name it—additionally adjustments over time.

Researchers have lengthy debated what the reason for this warping is, and a number of other hypotheses have been proposed to elucidate it. This consists of the affect of a hoop of darkish matter surrounding the galaxy, or the intergalactic magnetic area.

However, evaluation of information collected by the European Space Agency’s (ESA) Gaia area observatory has revealed the precession charge is way quicker than what we might count on to see if darkish matter or the intergalactic magnetic area have been inflicting it. Findings are revealed within the journal Nature Astronomy.

“We measured the speed of the warp using precise measurements from Gaia satellite for millions of stars. Based on our results, the warp is moving very fast, completing one rotation around the Galactic Center in 600 to 700 million years,” lead creator Eloisa Poggio, from the Turin Astrophysical Observatory, Italy, advised Newsweek. “For this reason, something more powerful—like an interaction with a satellite—would be needed to explain our results.”

In gentle of this discovering, the researchers say that the more than likely clarification for such a excessive warp pace is the Milky Way colliding with one other galaxy—an occasion that might contain extremely highly effective gravitational forces able to distorting the form of the galactic disk.

It just isn’t clear which galaxy might be behind the distorted form, or when such a collision may have taken place, in accordance with the scientists. A possible candidate is the dwarf galaxy Sagittarius, which orbits the Milky Way and is positioned round 65,000 light-years from Earth.

This galaxy is assumed to have had encounters with the Milky Way previously. For instance, a examine revealed within the journal Nature in 2018 advised that Sagittarius and the Milky Way almost collided between 300 and 900 million years in the past.

Astronomers predict that the Milky Way will finally devour Sagittarius fully.

According to the authors of the most recent examine, our photo voltaic system is comparatively unaffected by the warping of the Milky Way due to its location, away from the sides. “The sun is at the distance of 26,000 light-years from the Galactic Center where the amplitude of the warp is very small,” Poggio mentioned. “Our measurements were mostly dedicated to the outer parts of the galactic disc, out to 52,000 light-years from the galactic center and beyond.”

Milky Way warped shape
This illustration reveals the warped construction of the Milky Way.
Stefan Payne-Wardenaar; Inset: NASA/JPL-Caltech; Layout: ESA

The researchers say the most recent findings have been solely made potential by the unprecedented knowledge that has been collected by Gaia. The objective of the Gaia mission—which started six years in the past—is to create the most important, most detailed three-dimensional map of the Milky Way by surveying round one p.c of its estimated 100 billion stars. For every of those stars, the area observatory will precisely measure their location and movement across the Milky Way’s Galactic Center.

“With Gaia, for the first time, we have a large amount of data on a vast amount stars, the motion of which is measured so precisely that we can try to understand the large scale motions of the galaxy and model its formation history,” Jos de Bruijne, Gaia deputy undertaking scientist, mentioned in a press release. “This is something unique. This really is the Gaia revolution.”

Milky Way
Stock picture: The Milky Way as seen from the Earth.

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