Astronomers have traced a series of brief, enigmatic bursts of radio waves to a galaxy far, far away and indeed a long time ago — some three billion years or so.

But as much as you might be hoping or dreading it to be true, this is probably not E.T.

“We’ve joked about spaceship battles and death stars blowing up, but we think we can explain it with ordinary physics,” said Shami Chatterjee, a Cornell astronomer.

Dr. Chatterjee is the lead author of a paper published in Nature on Wednesday that details the search for the source of the radio waves known as “fast radio bursts,” intense pulses of radiation from the sky lasting only a few milliseconds. He also spoke at a news conference sponsored by the American Astronomical Society in Grapevine, Tex.

These have been disappointing times for those yearning for some alien direction from Out There. Last summer, Russian astronomers reported that they had recorded a promising-sounding signal from a star in the Hercules constellation, but they dismissed it when it became public as a freak bit of random radio noise, the astrophysical equivalent of a cosmic butt dial.