Speculative non-article.. From the last paragraph: He said: "A solar proton event and a short gamma-ray burst are both possible explanations, but based on the

Speculative non-article.. From the last paragraph: He said: "A solar proton event and a short gamma-ray burst are both possible explanations, but based on the rates that we know about in the Universe, the gamma-ray burst explanation is about 10,000 times less likely to be true in that time period."