|Manu||Date: Tuesday, 17-March-2020, 6:47 PM | Message # 1|
|Physicists Are Studying Mysterious 'Bubbles of Nothing' That Eat Spacetime|
A spontaneous hole in the fabric of reality could theoretically end the universe, but don't worry: physicists are studying the idea for what it can teach us about the cosmos.
By Carly Minsky
This article originally appeared on VICE US.
The universe might be on track to eat itself from the inside out.
Luckily for us, physicists studying the phenomenon, called “spacetime decay”, believe this is very unlikely. Still, the possibility is interesting enough to explore in mind-boggling detail, covering “bubbles of nothing” in spacetime, hidden extra dimensions, and a hypothetical observer hitching a ride on the outer surface of our universe.
The idea that in specific scenarios the universe would be entirely destroyed by an expanding bubble of nothing has been around since 1982, when theoretical physicist Edward Witten introduced the possibility of the universe eating itself in a paper in Nuclear Physics B journal. He wrote: “A hole spontaneously forms in space and rapidly expands to infinity, pushing to infinity anything it may meet.”
Given that a bubble of nothing has not in fact destroyed the universe, neither in the 13 billion years before Witten published his paper nor in the 38 years since, it would be reasonable for physicists to push it down the research priority list. But three physicists at the University of Oviedo in Spain and the University of Uppsala in Sweden argue that we can learn important lessons from an all-consuming, universe-destroying bubble in a wonderfully titled paper, “Nothing Really Matters”, submitted to the Journal of High-Energy Physics this month.
In particular, understanding the conditions for spacetime decay through a bubble of nothing is a step towards connecting the best theories about the tiniest building blocks of the universe—strings—with theories about space and time itself.
The unstable universe
It's commonly understood that a vacuum is a region of total emptiness, so it’s confusing to think that our entire universe which contains planet earth, distant galaxies and everything in between is almost entirely a vacuum. But the fact that our universe is mostly vacuum is part of the reason it exists in a relatively stable state.
Read more/source - https://www.vice.com/en_uk....acetime