What is the Hayflick limit? Is it the ultimate blockade to immortality?

Hayflick limit is basically how cells can only divide a certain number of times, due to telomeres.

It is related to aging, but perhaps not the "ultimate blockade to immortality"

"There seems to be myriad factors involved in programmed cellular death beyond the destruction of telomeres. "

http://morgana249.blogspot.com/2014/08/7-biologically-immortal-organisms-faces.html

Moreover, there are organisms that keep their telomeres lengthened and therefore they are immortal.

For example certain jelly fish, lobsters and plants are immortal.

However, being immortal doesn't prevent them from dying haha. Predators, disease, major environment changes can still kill these "immortal" organisms.

http://www.bbc.com/earth/story/20150622-can-anything-live-forever

So "Is it the ultimate blockade to immortality?"

From my perspective, yes it is the "ultimate" reason we are mortal. However, it wouldn't prevent us from dying. And humans who do have lengthened telomeres are humans who probably have .