Search FQXi


RECENT FORUM POSTS

ross nickel: "In the early 1980s I was watching a sci-fi movie taking place in a..." in Alternative Models of...

Pentcho Valev: "In 1905 Albert Einstein informed the world that, although time dilation is..." in Call for Research...

John Merryman: "The irony is this"expansion" is intergalactic, balancing the galactic..." in Is the Past Infinite?

Pentcho Valev: "Eckard, "Will you please perform the quantitative check I asked you for?" ..." in Call for Research...

Georgina Parry: "Thanks for the link. I didn't know that Einstein was so fiercely..." in Is the Past Infinite?

Chuck Stark: "As a Mathematics undergraduate with a Physics minor, this topic is near and..." in Trick or Truth? — Essay...

Anton Vrba: "Brendan, Wow what a fantastic essay topic, congratulations! After skipping..." in Trick or Truth? — Essay...

Peter Jackson: "John, It's clear that space can have 0 'condensed 'matter', but you've not..." in Alternative Models of...


RECENT ARTICLES
click titles to read articles

Quantum in Context
An untapped resource could provide the magic needed for quantum computation—and perhaps even open the door to time travel.

Spot the Difference to Reveal Exotic Particles
Questioning the symmetrization postulate of quantum mechanics and the notion that electrons are indistinguishable could reveal whether hypothetical new particles exist.

Life's Quantum Crystal Ball
Does the ability to predict the future—perhaps with quantum help—define the fundamental difference between living and inanimate matter?

The Quantum Truth Seeker
Watching particles fly through an interferometer might help to unveil higher-order weirdness behind quantum theory.

Quantifying Occam
Is the simplest answer always the best? Connecting Medieval monks to computational complexity, using the branch of mathematics known as category theory.


FQXI ARTICLE
December 20, 2014

The Black Hole Universe
Is our universe housed in a black hole? Or did it exist before the Big Bang? If so, we could solve the mystery of dark energy—surprisingly, it’s all down to the humble neutrino.
by Kate Becker
FQXi Awardees: Stephon Alexander
May 28, 2010
Bookmark and Share


STEPHON ALEXANDER
Haverford College
Your mission, should you choose to accept it, is to go undercover as a neutrino and investigate whether these elusive particles are driving dark energy and if they put the big in the Big Bang. The operation could take you to a universe inside a black hole, and lead you to investigate whether time stretched before the big bang.

Let’s start with a little bit more about your assumed identity as a neutrino. Your mother was a proton who met up with three other protons deep inside a star. There was some nuclear fusion, she transformed herself into a neutron, and you popped out. You didn’t stick around very long, though. You have no charge and almost no mass, so you barely interact with the other particles, zipping through space, stars, and planets almost as if they aren’t even there.

So far, that’s the standard life story of a neutrino. But Stephon Alexander, a physicist at Haverford College, Pennsylvania, is shaking up that formulaic plot. What if, he ponders, time and our universe existed before the Big Bang? What if this prior version of the cosmos contracted down to a finite size, bounced, and started to expand outwards again? In that case, neutrinos, usually dismissed as being a ghostly particles with little tangible influence, could have had an extremely profound effect on the cosmos.

Subatomic Sardines

Picture yourself as a neutrino in such a contracting universe, wedged against other neutrinos like so many subatomic sardines, one hundred of you crowding every cubic centimeter of space. Under such circumstances, you and your comrades could form a new state of matter called a neutrino condensate, Alexander hypothesizes. This would act something like a superfluid—a fluid that doesn’t lose energy to friction. (If you stirred some superfluid creamer into your superfluid coffee, it would just keep swirling around the mug, never settling down.)

Two types of physics—
neutrinos and dark energy
—appear to be built
from the same bedrock.
- Stephon Alexander
It’s a nice plot twist, but what does it have to do with the universe that we see around us? The answer is that a compressed neutrino condensate could produce some very familiar effects that as yet have no explanation. Energy from the condensed neutrinos would set the universe expanding—fast. Cosmologists already believe that soon after the Big Bang, the universe went through a short period of rapid expansion, known as "inflation," but they have not been able to figure out why it occurred. Now, with the help of a $65,000 grant from FQXi and colleagues at Penn State University and Haverford, Alexander is investigating whether the humble neutrino holds the key.

A bouncing universe is only one possibility for how a neutrino condensate might form. Another is based on the notion that a collapsing star could squeeze neutrinos into a condensate, on its way to becoming a black hole. In that case, our universe might actually have formed in the neutrino soup housed inside a black hole.

A universe in a black hole may seem like an outlandish idea, but if correct, we still live within a neutrino condensate, which could be causing the expansion of the universe to accelerate. Astronomers have observed such an acceleration, and usually attribute it to some mysterious “dark energy.”

A strange parallel between neutrinos and dark energy gives Alexander a hint that he’s on the right trail. Neutrinos come in three flavors, and they are able to flip, or oscillate, between them. Think of the neutrino as the ultimate dish of Neapolitan ice cream, which spontaneously transforms from vanilla to strawberry to chocolate and back again. Surprisingly, the frequency at which neutrinos flip from one flavor to the next seems to be linked to the density of dark energy in our universe.


NEUTRINOS—DARK ENERGY’S
SECRET INGREDIENT?

The Sudbury Neutrino Observatory
(pictured) found that neutrinos
oscillate between three flavors.

Credit: NASA
"This is very surprising," says Alexander. "Two different types of physics that should have nothing to do with each other" appear to be built on the same bedrock. Yet physicists still do not understand why neutrinos oscillate. Could it be that the flavor-flipping is the direct result of traveling through a neutrino condensate? "A neutrino moves in that medium like a boat moving in water," explains Alexander. Perhaps neutrino oscillation is like that boat bouncing on the waves.

Philip Phillips at the University of Illinois at Urbana-Champaign, an expert on what happens when exotic materials are squeezed down into new states of matter, finds the idea "truly novel." "Alexander has combined ideas from my field of condensed matter and put them to use in his own," he says.

While condensed matter physicists have produced examples of superfluids and condensates of other types of exotic matter, Alexander’s neutrino condensate cannot be cooked up in the lab because neutrinos are too slippery to capture and bundle together. But Alexander hopes to make testable predictions based on his theory that link the characteristics of neutrinos to the observed properties of dark energy. "We can use the universe as a laboratory to test particle physics," he says.

Lee Smolin, a theoretical physicist at the Perimeter Institute in Ontario, is a fan of Alexander’s original thinking. "He has a very fertile creativity combined with an independence of mind," he says.

So will neutrino condensation turn out to be the right answer to these cosmic riddles? Perhaps. As Smolin puts it, "We don’t know if it is true, but it is something that, so far as we know, might be true."

Comment on this Article

Please read the important Introduction that governs your participation in this community. Inappropriate language will not be tolerated and posts containing such language will be deleted. Otherwise, this is a free speech Forum and all are welcome!
  • Please enter the text of your post, then click the "Submit New Post" button below. You may also optionally add file attachments below before submitting your edits.

  • HTML tags are not permitted in posts, and will automatically be stripped out. Links to other web sites are permitted. For instructions on how to add links, please read the link help page.

  • You may use superscript (10100) and subscript (A2) using [sup]...[/sup] and [sub]...[/sub] tags.

  • You may use bold (important) and italics (emphasize) using [b]...[/b] and [i]...[/i] tags.

  • You may also include LateX equations into your post.

Insert LaTeX Equation [hide]

LaTeX equations may be displayed in FQXi Forum posts by including them within [equation]...[/equation] tags. You may type your equation directly into your post, or use the LaTeX Equation Preview feature below to see how your equation will render (this is recommended).

For more help on LaTeX, please see the LaTeX Project Home Page.

LaTeX Equation Preview



preview equation
clear equation
insert equation into post at cursor


Your name: (optional)



Important: In order to combat spam, please select the letter in this menu between 'I' and 'K':




Recent Comments


what's happen for this???

who can tell me . [url=http://www.designerhandbags001.com]DESIGNER[/url]


I am very happy to introduce you to our website, the main business is online Replica Designer Handbags, everything in our products, and a wide range, which are internationally renowned brands which include football, such as GUCCI, LV, COACH, CHANEL and so you love and you want to have, can be on our website to buy super discount prices, and Cheap Designer Handbags quality is very good oh. Visit our website, you will definitely gain something, and look forward to your arrival.


As for the Black Hole Universe it might be useful to see the following article

[record/827653]

read all article comments

Please enter your e-mail address:
Note: Joining the FQXi mailing list does not give you a login account or constitute membership in the organization.