Uppsala University researchers have devised a new model for the Universe and it just might solve the enigma of dark energy. These scientists propose a new structural concept that our Universe is riding on an expanding bubble in an extra dimension. Their new article, published in Physical Review Letters, explains into more detail but here’s the nutshell version.
The Universe is expanding at an ever accelerating rate. This is something they’ve already known for the past 20 years. Why is this happening? They say the universe is expanding because “dark energy” that permeates it throughout is pushing it to expand. However, understanding the nature of this dark energy is another matter; it is one of the paramount enigmas of fundamental physics.
Scientists have been (for a long time now) hoping that string theory will provide the answer. There have been models in string theory for the past 15 years already that have been thought to give rise to dark energy. String theory states that all matter consists of tiny, vibrating “stringlike” entities. So all matter in the universe may exist in strings that reach into another dimension.
Furthermore, the theory also requires there to be more spatial dimensions than the three that are already part of our everyday common knowledge. Although, several researchers are now asserting that none of the models proposed to date are workable and the theory has come in for increasingly harsh criticism.
Putting all the disbelief aside, cosmologists continue to search for answers and ways to prove their theory’s validity. Through this, they have come up with a new model with dark energy and our Universe riding on an expanding bubble in an extra dimension. In other words, this radical theory says our universe sits on an inflating bubble in an additional dimension. Dark energy is the inflating force in this bubble, the existence of which is supported by string theory.
An Uppsala University press release explains:
“The whole Universe is accommodated on the edge of this expanding bubble. All existing matter in the Universe corresponds to the ends of strings that extend out into the extra dimension. The researchers also show that expanding bubbles of this kind can come into existence within the framework of string theory. It is conceivable that there are more bubbles than ours, corresponding to other universes.”
They believe these bubbles to be rather stable, writing there’s “a strong indication in favor of the stability of these bubbles.” As if this all isn’t exciting enough already, there’s more…there could be more bubbles than just the one with our universe on it – with each one of those carrying another universe.
The research explains:
“In this context, the cosmology we see as 4D observers is not due to vacuum energy, but rather arises as an effective description on a dynamical object embedded in a higher dimensional space.”
Black holes can also be re-defined by this new theory. The scientists state:
“Gravitational collapse of the string endpoints in four dimensions results in an unstable black string solution in five dimensions.”
This model provides a new, different picture of the creation and future fate of the Universe. It may also pave the way for methods of testing string theory.