Are the Milky Way and the Andromeda Galaxy on a Collision Course?

A collision between the Milky Way and the Andromeda Galaxy could radically change our cosmic neighborhood. A new study takes a closer look.

FRANKFURT – It may sound fantastic, but it’s also scary: One day, our Milky Way galaxy and its neighboring Andromeda galaxy are expected to collide. The first recognition of this possible collision dates back to 1912, when American astronomer Vesto Slipher noticed that the light from Andromeda showed a shift toward the blue part of the light spectrum – indicating that it was approaching our galaxy.

Previous research, based on observations and calculations, predicted that a collision between the two galaxies would be inevitable within the next five billion years. This collision would not only radically change the structure of both galaxies, but would also catapult our solar system into an outer arm of the newly merged galaxy.

Are the Milky Way and the Andromeda Galaxy Already on a Collision Course?

However, new research based on data from the Gaia and Hubble space telescopes calls these assumptions into question. The research team incorporated the gravitational interactions of four large galaxies—the Milky Way, the Andromeda Galaxy, the Triangular Nebula (M33), and the Large Magellanic Cloud—into their models and concluded that the probability of a collision between the Milky Way and Andromeda is about 50 percent. The four galaxies are part of the Local Group, a collection of galaxies whose largest members are the Milky Way and Andromeda.

The new study, which so far only On the pre-print server Archive Published The theory, which has yet to be verified by experts, suggests that the potential collision of the giants – if it ever happens – will not occur for at least eight billion years. “We found that the uncertainty in the current positions, motions and masses of all the galaxies leaves room for very different outcomes, and there is about a 50 percent chance that there will be no merger between the Milky Way and Andromeda in the next 10 billion years,” said the research team.

Other galaxies affect the Milky Way and the Andromeda Galaxy.

Previous studies of the fate of the Milky Way and its neighboring galaxies have not taken into account the gravitational influences of other galaxies in the Local Group. These could affect both the Milky Way and Andromeda in ways that may or may not one day collide. M33 and the Large Magellanic Cloud could “dramatically and dramatically influence the orbits of the Milky Way and Andromeda,” the research team said in the study.

The researchers now hope to gain more accurate information about the future fate of the Milky Way and Andromeda with more data from the recently recalibrated Gaia space probe. “Future Gaia data will improve the constraints on self-motion, and the mass models will be continually improved,” the research group said. The only thing certain so far is that the two massive galaxies are approaching each other. Time will tell whether they will collide in a few billion years. (unpaid invoice)