Galaxy-collision simulator

Follow two galaxies through close passages, tidal tails and a gravitational merger lasting billions of years.

Milky Way–Andromeda-style encounterInitial approach

Galaxy A starsGalaxy B starsGas and young stars

Core separation780 kpc

Relative velocity110 km/s

Elapsed time0.00 Gyr

Close passages0

Merger progress0%

Core separation

Particle populations

Stars rarely collide

Galaxies overlap, but individual stars are so widely separated that direct stellar collisions are extremely unlikely. Gravity reshapes their collective orbits.

Tidal tails

Uneven gravitational forces pull stars and gas into long bridges and tails. Prograde encounters often produce especially prominent structures.

Repeated passages

Dynamical friction transfers orbital energy into the surrounding stars and dark matter, drawing the galactic cores together into a merger remnant.

Model note: Representative particles respond to softened moving galaxy potentials. Particle sizes, timescales, gas behaviour and friction are educational approximations rather than a full N-body hydrodynamic calculation.