Andromeda–Milky Way collision The Andromeda–Milky Way collision
is a galaxy collision predicted to occur in about 4 billion
years between the two largest galaxies in the Local Group—the
Milky Way (which contains the Solar System and Earth) and the
Andromeda Galaxy. While the Andromeda Galaxy contains about 1
trillion (1012) stars and the Milky Way contains about 300
billion (3×1011), the chance of even two stars colliding is
negligible because of the huge distances between the stars. For
example, the nearest star to the Sun is Proxima Centauri, about
4.2 light-years (4.0×1013 km; 2.5×1013 mi) or 30 million (3×107)
solar diameters away. If the Sun were a ping-pong ball, Proxima
Centauri would be a pea about 1,100 km (680 mi) away, and the
Milky Way would be about 30 million km (19 million mi) wide,
about 1⁄5 the distance from the Earth to the Sun. Although stars
are more common near the centres of each galaxy, the average
distance between stars is still 160 billion (1.6×1011) km (100
billion mi). That is analo