Milky Way's impending collision with its neighbor, Andromeda, will result in the two galaxies merging together

In the vast expanse of the universe, two titans are set to collide in an epic event known as the Andromeda-Milky Way collision. This cosmic encounter, which is inevitable due to the trajectory of Andromeda's satellite galaxies, was the subject of a recent study published in the April 2021 issue of a certain website.

The simulation of this collision paints a fascinating picture. Over billions of years, the two galaxies will engage in a series of close passes, their structures distorted in the process. The details of this dance depend on the intricate details of the galaxies' structures and the assumptions about the haloes of dark matter that surround them.

The authors of the study estimate that the collision will occur about 10 billion years from now, a timeline longer than in previous studies. This collision will result in a new, larger galaxy, named 'Milkdromeda'. Unlike its forebears, this new galaxy will be an elliptical galaxy.

At the heart of this new galaxy, a binary black hole pair will form. The supermassive black holes at the centers of both the Milky Way and Andromeda will interact, spiralling inward due to the influence of their surroundings. This interaction will emit gravitational waves, a ripple in spacetime itself.

As the black holes draw closer, they will lose energy through gravitational waves, driving a final inward spiral and merger in about 17 million years. This merger will be a significant event, with the gravitational wave signal detectable by ESA's LISA mission, but not by LIGO.

Sadly, the Sun will not live long enough to find a home in the new galaxy. However, the findings of this study may help us compare the fate of the Milky Way's black hole with similar events elsewhere.

It's worth noting that measurements can only tell us about the motion directly towards or away from the observer. For instance, measurements of the Doppler shift of the Andromeda Galaxy's spectral lines indicate it is getting closer to our galaxy.

The exact time of the collision between the Andromeda Galaxy and the Milky Way is generally estimated to be in about 4.5 billion years. This study provides us with a fascinating glimpse into our galaxy's future, a future that involves a cosmic collision of epic proportions.

The article was read by Chris Lintott and can be found online at arxiv.org. As we look to the stars, we can't help but wonder what lies ahead in our galaxy's grand cosmic dance.

Milky Way's impending collision with its neighbor, Andromeda, will result in the two galaxies merging together