#Cosmology #Astrophysics #AstroKatie The End of Everything (Astrophysically Speaking) is a lively antidote to our otherwise cheerful times. Instead of agonizing over a pandemic, political polarization, and economic upheaval, why not fret over the end of the entire universe?! All jokes aside, why bother studying our universe’s demise? Well, as Mack says, contemplating our end helps us “understand the fundamental nature of reality itself.” Known as AstroKatie to her legions of followers, Mack is a theoretical astrophysicist and an assistant professor of physics at North Carolina State University. She contemplates such cosmological catastrophes as the Big Rip, the heat death of the universe, and, most terrifyingly, vacuum decay—the possible transition from the false “metastable” vacuum state we may currently be enjoying into its true minimum, or ground state, which would cause the instantaneous disintegration of baryonic matter, among other day-ruining effects. In her skillful hands, we learn that although our cosmic comeuppance won’t be pretty, we at least have billions of years before it will occur. That is, unless vacuum decay—discussed with the perfect blend of academic rigor and poetic license—is the ultimate culprit of our doom, in which case cosmic catastrophe may occur as you read this sentence. Following Yogi Berra’s dictum that “it’s tough to make predictions, especially about the future,” Mack warns us that how the universe will end is much less certain than how it began. Although she largely eschews the typical approach of recapitulating cosmology’s vast history, she does note that our knowledge of the origin of the universe also was once more nebulous. Well into the 20th century, there were many rival cosmogonies, including the cosmic egg, Lemaître’s primeval atoms, and even the biblical book of Genesis. Nevertheless, cosmic eschatology has gotten short shrift. The End of Everything was published exactly 100 years after the famous debate between astronomers Harlow Shapley and Heber Curtis over whether the Milky Way galaxy was the entire universe or other galaxies were in the cosmos. The so-called Great Debate was resolved three years later when Edwin Hubble demonstrated that the object then known as the “great spiral nebula” in Andromeda was not a nebula at all but an entirely separate galaxy. Further observations by Hubble proved that the universe was expanding, which prompted speculation about what happened when its expansion began. Scientists eventually settled on the Big Bang theory accepted today. All the while, attention to the opposite end of the timeline—if there is one—has been sparse, and speculation reigns. Mack’s surprisingly lively account of the Big Bang’s end-of-time counterpart ... https://www.youtube.com/watch?v=NM41nR4uk24