This is not a visible light image, thus the ghostly aspect. It is an X-ray portrait (I love the 50s sci-fi sound of the term "X-ray") of the center of the Abell 400 galaxy cluster, a dance of high energy particles as two massive black holes orbit each other. These black holes - the two bright dots at the center - are gravitationally bound and will one day collide, in a burst of gravitational waves and cosmic waves that will be seen and felt quite literally across the universe.
The plumes shooting along the diagonal of the image are jets of super-charged particles shooting out from the poles of the things. The swept back appearance of the jets is due to both black holes rushing through a cloud of hot gas at 1200 kilometers per second. Think of a smoker exhaling smoke out of the open window of a speeding car.
The Chandra X-Ray Observatory took the picture.
