What annoyed me (and I was annoyed) is the utter hypotheticalness of phantom energy. That is a disputable point - as they point out, there are models in which fields with the properties of phantom energy pop up, it wasn't invented solely for the purpose of ending the universe in finite time. You could counter that by saying, are those models physically motivated, or are they just exploring mathematical possibilities? Ultimately, I think "death by phantom energy" belongs on someone's exhaustive lists of "possible causes of human extinction", but it's way down the list, and belongs in a the specific subcompartment of "possible cosmological causes of human extinction", with an annotation that there's no actual evidence that phantom energy exists.

Also, "end of the universe as soon as 8.7 million years from now" is like saying "end of the earth as soon as asteroid impact one week from now" - or whatever is the minimum possible time from Earth that an asteroid could be while still being currently undetected. (Except we know that there are asteroids, and we don't know that there is phantom energy, so the analogy isn't exact. So maybe it's more like "end of Earth by expanding sphere of planet-killing von-Neumann replicators that's not yet visible to astronomers, as soon as a few thousand years from now".) Even if you decided to believe in phantom energy, you have no reason to expect the end in millions of years, rather than billions or trillions of years.

I would add one more thing - phantom energy may appear to be possible, only because we still don't understand physics well enough. Further conceptual progress in quantum gravity, and further progress in making use of the deep clues in particle physics, will eventually get us to the point that there will be a rational consensus on something more than "standard model plus gravity". At that time, the proliferation of theoretical ideas over the past 35 years (since the standard model was assembled) will be put into its proper perspective - it was an attempt to discover the next layer of truth by running in all possible directions. But there's only one truth, and once we get to the next level, whether by progress in theory or progress in experiment, most of that speculation will only be of historical interest.

What's up with the insinuation that this is "theological physics"?

It considers a time scale so long that the possibility of it ever being empirically tested is vanishingly small.

I'm interested in the new kinds of singularities being postulated here, that's the main thing.

There's really no relevance to LW to be found here.

Downvoted for telling people you're downvoting, contributing to a trend within this thread of increased emphasis on semantics and insults.....(I'm not proud of what I've done here)