https://en.wikipedia.org/wiki/False_vacuum_decay#Bubble_propagation https://en.wikipedia.org/wiki/False_vacuum_decay#Bubble_prop... The vacuum can only expand

https://en.wikipedia.org/wiki/False_vacuum_decay#Bubble_propagation https://en.wikipedia.org/wiki/False_vacuum_decay#Bubble_prop... The vacuum can only expand at the speed of light. Only a portion of the universe would be destroyed. The universe would still be unaffected because galaxies located further than 4,200 megaparsecs (13 billion light-years) away from each other are moving away from each other faster than the speed of light while the vacuum decay cannot expand faster than the speed of light.