We only have Kirk's theory that it was a relic of a long ago conflict. Spock had identified it's course as coming from outside of our galaxy, whether that meant from a race living in space stations beyond the rim or another galaxy itself is never explained and if the DDM travelled here from another galaxy then without super-light speed it would have taken a thousand years or more and would it have had a stockpile of energy to make it here? Seeing the weapon hitting the energy barrier would have been awesome and I wonder if anyone has ever done a video of it and put it on YT?
I thought Andromeda was our closest galactic neighbour? A satellite of the Milky Way seems a bit off to me as the home to the Planet Killer, I'd be surmising a large spiral cluster with many hundreds of planets...

JB
Your comment is awakening my inner Spock.
No, Andromeda is not the nearest galaxy to our mIlky Way Galaxy. In fact there are dozens of small galaxies much closer to our gaalxy.
https://en.wikipedia.org/wiki/List_of_nearest_galaxies
https://en.wikipedia.org/wiki/Andromeda_Galaxy
https://en.wikipedia.org/wiki/Local_Group
Your term "spiral cluster" is inaccurate. There is no astronomical term "spiral cluster"..
In astronomy, star clusters, galaxies, and clusters of galaxies are three separate things.
Star clusters are clusters of stars. The two main types are galactic or open clusters, and globular clusters. Open clusters are smaller and contain only hundreds or thousands of stars. Globular clusters are larger and densely packed, containing tens of thousands of stars.
The three main forms of galaxies are irregular, elliptical, and spiral. IIrregular and spiral galaxies contain open star clusters. All three types of galaxies usually have globular clusters, tens, hundreds, or thousands of them.
The smallest sized dwarf galaxies might have only about a million stars each, which is still somewhat larger than the largest globular star clusters. Galaxies vary greatly in size, with the largests ones having trillions of stars.
Glaxies are usually grouped into clusters of galaxies, and many clusters of galaxies are grouped into superclusters of galaxies.
So there is no such thing as a "spiral cluster" A large spiral galaxy would have hundreds of billions of planets, not a few hundred planets. Even the tiniest spiral galaxies would have millions of planets.
Andromeda is the closet full "galaxy" but, there are a number of smaller clusters like the Greater and Less Magellanic Clouds (along with a bunch of others) that are much closer.
LIke Johnnybear, you are arousing my inner Spock by confusing star clusters with galaxies.
Astronomers never refer to other galaxies as clusters. The Greater and Lesser Mgellanic Clouds are defined by astronomers as galaxies, not cluseters. Irregular galaxies to be precise.