Comment by dbingham

It is every bit as irrational to dismissively rule out "aliens" as it is to rush to declare it the definitive answer.

It is a valid possible answer that should be included in the possibilities as we try to figure out what caused the acceleration. Right now, lots of things are being proposed. And many of them are seemingly being ruled out. It remains to be seen what the answer will be.

The physics and history of science books I read when I got my degree did not seem to include sneering contempt for those who thought pulsars could be alien in origin. I rather recall a tone of disappointment as they described how we figured out that they weren't alien. The Fermi paradox remains one of the great mysteries of astronomy and cosmology and a lot of people, both professional and amateur are still fascinated by it.

Extraordinary claims do require extraordinary evidence, but academics who sneeringly dismiss extraordinary claims as even a possibility are every bit as toxic to the rational advancement of science as those who advance those claims without enough evidence.