Using a telescope in Chile, astronomers were able to record the picture millions of kilometres away.
An Arizona-based NSF lab has just reported an astounding finding they made two days after last month's planetary-defense test.
Dust and other debris ejected from the impact crater can be seen growing into a comet-like tail in the picture.
Which is more than 6,000 kilometres in length.
The tail is predicted to lengthen and spread even farther, eventually becoming so faint that it cannot be seen by the naked eye.
After then, the material "will be like any other dust flying throughout the solar system,".