On Sept 2016, a group of astronomers have found a new X-Ray source in the universe. This is nothing unusual, the universe is full of X-Ray emitting stars, galaxies and the like. But in this case, the source is unusually weird. They’re coming from the planet, Pluto.

Now, Pluto presenting us with something puzzling is nothing new. Ever since the New Horizons probe passed by and explored Pluto last year the planet has tossed enigma after another at us ranging from the planet is geologically active to the planet having an escaping atmosphere that is partly depositing itself on its main moon. But these new developments may top even those mysteries.

Submitted by Chandra on Wed, 2016-09-14 10:36

Researchers Carey Lisse and Ralph McNutt and their colleagues using the Chandra X-Ray Observatory have found that Pluto, a frozen Kuiper Belt object, is emitting X-Rays. This is unique for the outer solar system, the furthest planet known to be emitting such things is the gas giant Saturn. Everything else is quiet, even the ice giant planets. Everything else is quiet, even the ice giant planets. Very mysterious indeed, but we do have some ideas on how this can be happening.

Planets, even outer minor planets, are bombarded by the solar wind that streams off the sun. What’s interesting however is that Pluto lacks a magnetic field and has no apparent way to produce X-Rays on its own. But we do have a clue. Comets produce X-Rays when the gaseous tail they emit interacts with the solar wind. Pluto seems to be doing the same thing somehow, but there are problems.

Pluto’s atmosphere, as imaged by New Horizons.
Image credit: NASA / JHUAPL / New Horizons / LORRI.

That would suggest that Pluto not only has an atmosphere but also a substantial tail somewhat like a comet. Just such a thing was seemingly detected by New Horizons but again seems significantly weaker than it should be to produce all those X-Rays, though there are other indications it could be. Another possibility is that interplanetary magnetic fields might be the culprit and are focusing the solar wind around Pluto. Still, further, a torus of gas centred on Pluto’s orbit might do the trick.

The theories abound and no doubt will multiply, and this is especially interesting since this observation using Chandra was originally met with much opposition from the scientific community and almost didn’t happen. Few thought Pluto could emit X-Rays. Why devote telescope time to a wild goose chase? In this case, the goose was easily caught it seems. But we won’t know what’s going on here for sure until more powerful and accurate observations can be made of the X-Ray emissions. But chalk yet another one up for Pluto, it’s mystified us yet again which it’s done repeatedly for the last year. Personally, I suspect it’s just taking revenge for having its planet status revoked and downgraded to minor planet.

As an aside, I haven’t verified it yet, but I think Pluto is the first alien world to technically be visited by its discoverer. A small number of Clyde Tombaugh’s ashes were aboard the New Horizons spacecraft. I thought that was cool.