david-butler 3 years ago
science-cosmology specialist #Space and Time

How Far Away Is It | 15 - Colliding Galaxies

In this segment of our “How far away is it” video book, we cover interacting or colliding galaxies.

We describe what it means for galaxies to collide given the great distances between stars within each galaxy. We then take a look at some of the interacting galaxies photographed by the Hubble Telescope.


These include: The Antennae Galaxies, The Mice, NGC 2207 with IC 2163; Apr 256; ESO 576-69; APR 142; NGC 6240; the Tadpole Galaxy; UCG 1810 with UCG 1813; the spectacular APR 147; NGC 454; South America Galaxy; and ZW II 28.


We spend some time on peculiar galaxy NGC 7603 with its multiple red-shift objects that challenge well accepted theories on Dark Matter and Cosmology.

Next, we discuss how we go about seeing a process that takes a billion years by observing interactions at various stages along the process as understood by computer simulations.


Here we show a few that illustrate the phases of an interaction: the initial approach with NGC 6786 and LEDA 62867; first contact with VV 304A and VV 304B; penetration with Mayall’s Object; out the other side with ESO 77-14; wrap around with VV 705; and merge with The Owl. 

We end with another simulation.


This time it’s the collision between Andromeda and the Milky Way.

David Butler
science-cosmology-specialist