It might sound like the tagline from an old science fiction B-movie (It Came from the Ant Nebula!), but as it turns out, there really is a powerful laser beam shooting out of the distant Ant Nebula some 8,000 light-years away. Is this an attempt at intergalactic communication, or is some strange and unknown natural phenomenon afoot?
Probably the latter. Although would we really be able to tell the two apart? The anomalous laser from the Ant Nebula was discovered by the European Space Agency (ESA) at the Herschel space observatory, one of the largest infrared telescopes in space. Recent observations conducted by Herschel have revealed an intense laser emission coming straight from the core of the nebula, and scientists aren’t quite sure exactly what is producing the beam.
There are a few extremely rare phenomena which can generate lasers inside of nebulae. Curiously, astronomer Donald Menzel was the first to suggest that lasers could be produced by nebulae in space, and Menzel also happens to be the astronomer who discovered the Ant Nebula (its official name is Menzel 3). According to Menzel’s theories, certain types of radioactive gases can accrete in dense clouds close to stars, and these gases can amplify stars’ light enough to produce beams of laser light.
We detected a very rare type of emission called hydrogen recombination laser emission, which is only produced in a narrow range of physical conditions. Such emission has only been identified in a handful of objects before and it is a happy coincidence that we detected the kind of emission that Menzel suggested, in one of the planetary nebulae that he discovered.
The Ant Nebula gets its name from the fact that it consists of two lobes of gas which resemble the head and thorax of an ant. While I'm sure there are rare examples in which lasers can be generated by clouds of radioactive gas, I just have to wonder: if this was an alien race's attempt at communication, would we even know it? What might the horrible ant creatures of the Ant Nebula be trying to tell us?