NASA - NASA's Hubble Shows Milky Way is Destined for Head-On Collision
http://www.nasa.gov/mission_pages/hubble/science/milky-way-collide.html
x First Row, Left: Present day.
x First Row, Right: In 2 billion years the disk of the approaching Andromeda galaxy is noticeably larger.
x Second Row, Left: In 3.75 billion years Andromeda fills the field of view.
x Second Row, Right: In 3.85 billion years the sky is ablaze with new star formation.
x Third Row, Left: In 3.9 billion years, star formation continues.
x Third Row, Right: In 4 billion years Andromeda is tidally stretched and the Milky Way becomes warped.
x Fourth Row, Left: In 5.1 billion years the cores of the Milky Way and Andromeda appear as a pair of right lobes.
x Fourth Row, Right: In 7 billion years the merged galaxies form a huge elliptical galaxy, its bright core dominating the nighttime sky.
