Gaze upon the cosmic mystery of the Waterfall Nebula

Just like regular clouds here on Earth, it's easy to see shapes in the interstellar clouds of dust and gas that make up nebulae. But this waterfall-shaped nebula is particularly spectacular... and nobody quite knows why it looks like that.

Located in the Great Orion Molecular Cloud Complex, nebula HH-222 is considered one of the most mysterious objects in known galaxy. A NASA astronomer explains why:

The elongated gaseous stream stretches about ten light years and emits an unusual array of colors. One hypothesis is that the gas filament results from the wind from a young star impacting a nearby molecular cloud. That would not explain, however, why the Waterfall and fainter streams all appear to converge on a bright but unusual non thermal radio source located toward the upper left of the curving structure.

Another hypothesis is that the unusual radio source originates from a binary system containing a hot white dwarf, neutron star, or black hole, and that the Waterfall is just a jet from this energetic system. Such systems, though, are typically strong X-rays emitters, and no X-rays have been detected. For now, this case remains unsolved. Perhaps well-chosen future observations and clever deductive reasoning will unlock the true origin of this enigmatic wisp in the future.

Via NASA.