Dark Matter Expanding The Universe?

According to this theory, in the far distant future(millions of years) the earth's night sky will be far lonelier place. With the stars far fainter than they are now.

Were it not for dark energy, a mysterious repulsive force in the universe, our Milky Way galaxy would've long since crashed into its only neighbor, Andromeda. And instead of being lonely travelers in space, the galaxies would be nestled in the Virgo cluster, with hundreds more neighboring galaxies so close they'd be visible to the naked eye.

NASA/APOD

"The most distant object easily visible to the unaided eye is M31, the Andromeda galaxy some two million light-years away. If not for the mysterious effects of dark energy, Andromeda and other galaxies in the cluster would be nearer to -- and perhaps colliding with -- the Milky Way."

-