The Milky Way is part of the set of galaxies known as the Local Group, formed by several dozens of galaxies and with an estimated diameter of about 10 million light years. Our galaxy and Andromeda are the two most massive galaxies in the group.
The galaxies of the Local Group also interact with each other by their gravitational force. To predict the future interaction between the Milky Way and Andromeda, it is necessary to know their relative movement, which is not easy to measure. In particular, the tangential velocity between one and the other is the one that presents the most difficulties to be measured. Until the beginning of this year, the results obtained with the Hubble Space Telescope indicated a very small tangential velocity, so it was expected that in the future there would be an almost direct collision between the two galaxies. Recently, the results obtained with the European mission Gaia indicate a greater tangential speed, so it is possible that the collision with Andromeda is less direct. Based on these results, it is estimated that the Milky Way and Andromeda will merge in about 6,000 million years, although the collision process will begin 2,000 million years ago. [wp_ad_camp_3]
The Sun will not run any risk during this process. The density of the stars in space is too low for there to be a reasonable likelihood of direct collision with other stars or even a very close approach that may alter the stability of the planetary system.
But the Sun’s orbit around the Milky Way will certainly be affected. Although it is not possible to determine the final destination with complete certainty, once the collision process ends, it is very likely that the Sun will end up with an orbit much further away from the center of the galaxy than now. The new galaxy will be very different from the current galaxy, since it will be an elliptical and non-spiral galaxy such as the Milky Way and Andromeda.