Category Archives: Cosmology

Awarded 2nd place in inaugural Buchalter Cosmology Prize

My recent work entitled “Precision Tests of Parity Violation Over Cosmological Distances” with Brian Keating and Brad Johnson was awarded 2nd place in the first annual Buchalter Cosmology Prize!  The announcement was made today at the American Astronomical Society meeting in Seattle.

The $5,000 Second Prize was awarded to Drs. Jonathan Kaufman and Brian Keating of the University of California, San Diego, and Dr. Brad Johnson of Columbia University, for their work entitled “Precision Tests of Parity Violation Over Cosmological Distances”, recognized by the judging panel as “an inventive proposal to significantly enhance cosmic microwave background polarization measurement, enabling new potential tests of fundamental physics.”

In our work, we motivate the use of current Cosmic Microwave Background (CMB) polarization telescopes for studying parity violating and Lorentz-invariance violating physics, and we propose a new calibration device to accurately separate these affects from instrumental noise.

Dr. Buchalter stated:

“These inaugural prize winners represent the kind of innovative thinking and novel ideas that might lead to huge leaps forward in our understanding of the universe.”

I am thrilled and honored to have been awarded this prize!

 

The full press release can be found below.

 


First Annual Buchalter Cosmology Prize Recognizes Innovative Ideas and Discoveries

Seattle, WA – January 6, 2015 (9:20 AM PST) – The winners of the 2014 Buchalter Cosmology Prize were announced today at the 225th meeting of the American Astronomical Society in Seattle, Washington. The annual prize, created by Dr. Ari Buchalter in 2014, seeks to reward new ideas or discoveries that have the potential to produce a breakthrough advance in our understanding of the origin, structure, and evolution of the universe.

The $10,000 First Prize was awarded to Dr. Marina Cortês of the Perimeter Institute for Theoretical Physics, the Institute for Astronomy at the University of Edinburgh, and the Centro de Astronomia e Astrofısica da Universidade de Lisboa and Dr. Lee Smolin of the Perimeter Institute for Theoretical Physics, for their work entitled “The Universe as a Process of Unique Events” published in Physical Review D and recognized by the judging panel as “a remarkable approach for introducing the irreversible flow of time into the foundations of physics.”

The $5,000 Second Prize was awarded to Drs. Jonathan Kaufman and Brian Keating of the University of California, San Diego, and Dr. Brad Johnson of Columbia University, for their work entitled “Precision Tests of Parity Violation Over Cosmological Distances”, recognized by the judging panel as “an inventive proposal to significantly enhance cosmic microwave background polarization measurement, enabling new potential tests of fundamental physics.”

The $2,500 Third Prize was awarded to Dr. Carroll Wainwright of the Santa Cruz Institute for Particle Physics (SCIPP) and Department of Physics at the University of California, Santa Cruz; Dr. Matthew Johnson of the Department of Physics and Astronomy at York University and the Perimeter Institute for Theoretical Physics; Dr. Hiranya Peiris of the Department of Physics and Astronomy at University College London; Dr. Anthony Aguirre of the SCIPP and Department of Physics at the University of California, Santa Cruz; Dr. Luis Lehner of the Perimeter Institute for Theoretical Physics; and Dr. Steven Liebling of the Department of Physics at Long Island University, for their work entitled “Simulating the Universe(s): from Cosmic Bubble Collisions to Cosmological Observables with Numerical Relativity”, published in the Journal of Cosmology and Astroparticle Physics and recognized by the judging panel as “a significant advance in linking theoretical predictions with potentially observable signatures of bubble universes in a multiverse cosmology.”

Dr. Buchalter, a former astrophysicist turned entrepreneur, was inspired to create the prize based on his own research and experience in cosmology. “I believe that significant breakthroughs in cosmology still lie ahead of us, but to get there, we may need to alter, challenge, or even break some currently accepted paradigms,” said Dr. Buchalter. “These inaugural prize winners represent the kind of innovative thinking and novel ideas that might lead to huge leaps forward in our understanding of the universe.”

The prestigious judging panel for the prize included several theoretical physicists noted for their work in cosmology, including Dr. Sean Carroll of the California Institute of Technology, Dr. Robert Caldwell of Dartmouth College, and Dr. Joao Magueijo of Imperial College London.

The Beginning of the Universe (as Douglas Adams might tell it)

As a huge fan of the Hitchhiker’s Guide to the Galaxy series, I’ve often toyed with the thought of how Douglas Adams would explain the Inflationary Big Bang model.  So here’s my best guess… Happy Towel Day!!!

 

In the beginning…

Well, the beginning of what we call time, which is this funny little dimension that seems to prefer running in one direction when all the other dimensions don’t rightly seem to care.  In this beginning there was nothing.  Not nothing in the sense of the absence of anything but in the absence of everything that we have grown to love.  Also politicians.  This nothing was fidgety and would muck about mindlessly and was happy to do so.   One day, or more accurately, one trillionth of a trillionth of a trillionth of a second, a theoretical concept which has been wrongly described as a ball rolled down another theoretical concept which has been even more wrongly described as a hill until it stopped for reasons that could properly be described as mysterious.

This rolling inflated the nothingness from not quite much smaller than a soccer ball to not quite significantly larger than a very large size, forcing the nothingness to become somethingness, and really ruining its fraction of a second.

This newly founded somethingness begat more somethingness — stars, galaxies, humans, taxes, deep-fried corn dogs, and the mosquito.  And as Arthur Dent realized this, he decided it would have been better if he had not gotten out of bed today.

The death of a Universe

A few days ago, the person working the register at Trader Joe’s asked me how the Universe will end.  Sort of an odd question to ask a stranger but I suppose if you ask enough people, eventually one will be a cosmologist… (or perhaps my NASA t-shirt and general “physicist-y” look labeled me as a person who might have an answer)

On the surface, this question seems completely speculative and of the “tree falling in the woods” variety, designed to be mental Drano — but we have theories about this rooted in honest-to-goodness science!

We live in a Universe which experienced a Big Bang.  Essentially, this means there was some kick (Inflation) which started an expansion of the Universe.  There is also matter in our Universe, both “normal” (baryonic) and “dark,” which interacts via gravity; creating clumps of matter, then larger clumps of matter, then stars, galaxies, etc.  These two effects oppose each other, the expansion pushing everything apart and gravity trying to pull everything back together.  We can then imagine three scenarios: gravity wins, the expansion wins, or they both shake hands and call it a draw.

Gravity 1, expansion 0

If the force of gravity exhibited by the matter in our Universe is more powerful than the expansion, then this will counteract the expansion, slowing it down.  Eventually, the expansion will stop and then reverse!

Imagine throwing a bucket full of marbles into the air. [Note: do not attempt, or at least wear a helmet!]  At first, the marbles will fly upwards with giddy abandon, laughing in the face of Earth’s gravity.  These marbles will reach a maximum height, stop, and then fall back to Earth, defeated.

As all the matter in the Universe is attracted via gravity, we would eventually collapse into one giant cosmic black hole.  A Big Crunch.  The physics in this cosmic singularity break down, but it is theorized that we could end up with another Big Bang and thus a cyclic, bouncing Universe.

Expansion champion

Now if the expansion is more powerful than the gravitational interaction of all the matter in the Universe, we end up with a very different (though no less terrifying) cosmic death.

Here, the Universe expands and expands.  As it expands it cools.  Photons traveling while the Universe expands around it become redshifted until they are practically imperceptible.  The space in between galaxies will eventually expand so fast that the all the galaxies will disappear from each other’s skies.  Far in the future, all the Universe’s stars will fizzle out.  Eventually, the Universe will equilibrate to one extremely low temperature, ceasing to do anything particularly interesting and being completely inhospitable to life.  This is known as the Big Freeze.

Ok, we’ll call it a draw

If the gravitational attraction and expansion balance each other out, we would still have the same end as above.  As before, all the stars will burn out eventually.  The Universe will equilibrate at a very cold temperature and no life will be able to exist.

Expansion cheats

In my simplified model of the Universe that I’ve used so far, I’ve ignored a major component (though it has been implied): Dark Energy.  Dark Energy is a mysterious “anti-gravity” which is driving the accelerated expansion of our Universe.  If the expansion of space-time accelerates exponentially, eventually all the galaxies will be alone.  Then solar systems.  Then planets.  Eventually, atoms themselves will be ripped apart due to the rapid expanding of space-time in their subatomic structure.  Everything as we know it will be destroyed by this accelerating expansion.  This is aptly named the Big Rip.

e) none of the above

Ok, so there are more theories as to what could potentially happen, some extremely strange.  Perhaps the most entertaining is that the vacuum of space is actually a “local minimum” in energy — that is, our Universe sits on a plateau and we could roll down the hill at any moment, and into oblivion.  Although I’m sure the Mayans knew this all along, we primitive space-men will have to use our particle accelerators to probe for evidence that we live in a stable Universe.  Spoiler alert: we probably do.

 So what’s our prognosis?

The good news is (aside from the “false vacuum” death), all these unceremonious ends are tens of billions of years away at the earliest.

From cosmological measurements of the Universe, we can see that the expansion is winning, and is even accelerating.  So it seems like it’s a Big Freeze or Big Rip for us.  But considering all the catastrophic cosmic catastrophes that are likely to happen to our tiny little blue dot in the next few billion years, I wouldn’t lose sleep over it.

No such thing as nothing

The most common question I’m asked when describing the history of the Universe is: “what came before the Big Bang?”  This is a wonderful question, and it is from questions like these that we now have a sharp picture of our cosmic evolution; however, I have found that this question is rooted in a flawed understanding of the nature of the Universe.

I should clarify that I’m not talking about “what was going on prior to the Inflationary scale,” but “how can we get our Universe from nothingness.”  The answer is simple: There is no such thing as nothing!

The lonesome crowded cosmos

We think of space as being empty.  To some extent, that’s accurate.  If we look out into the vastness of space, we see around one atom per cubic centimeter.  Not exactly a party.  However, if we look for radiation left over from the Big Bang, we see that there are over 400 photons (discrete light particles) per cubic centimeter (on average).  There are even ~300 neutrinos (very light particles that travel close to the speed of light) per cubic centimeter everywhere.  The vacuum of empty space is teeming with stuff!  Much like physicists at a party, these particles don’t interact much and therefore aren’t terribly interesting out there.

The spaces between galaxies are also full of mysterious Dark Matter and Dark Energy, which are exciting unknowns in our standard model that physicists love to use to garner more hits on their blog posts (fingers crossed!).

But these examples aren’t what I mean when I say that there’s no such thing as nothing.  This is meant to show an example of how we can mis-classify space as being empty based on our mind’s bias towards things we can touch, taste, hear, smell, and see.  To really see nothing in a new light, we need to get quantum, baby.

Quantum of Solace

Quantum mechanics is really a triumph of human understanding. (Nice work everyone, beers are on me.)  We no longer think of particles as being discrete objects but probabilities.  That last sentence should cause a furrow on your brow.  The scales described by quantum mechanics are so foreign to our intuition that everyday concepts like position and speed don’t apply.  Instead of saying an electron is here at point x, we instead say that there is some probability of finding an electron in some range of positions.  We don’t know exactly where it is as words like “exactly” don’t mean anything in the quantum world!

So what does this have to do with the emptiness of space?  Everything!

If we look at the most absolute nothingness that we can find and we zoom in to the smallest scales, we can infer that the emptiness is a hotbed of quantum activity!  Particles are popping in and out of existence so quickly that you or I wouldn’t even say they existed.  There is energy in the vacuum and we can see it (check out the Casimir effect for more information).

Something from nothing

Now let’s roll back the clock to “before” the Big Bang, as people who pose this question would call it.  We know that our proto-Universe must have been very small, and was thus in the quantum regime.  If, by some mechanism, these quantum fluctuations were amplified so that they became very large, then they exit the quantum mechanical regime and can become physical particles (as we would think of them).  We call this mechanism Inflation (which my group believes we may have detected).

So it’s not that there was nothing and then suddenly there was something, but that the Universe was in a state that was governed purely by quantum mechanics.  Inflation then amplified quantum fluctuations in our proto-Universe onto large scales that then became our Universe as we know it.

Because of quantum mechanics, there is no such thing as nothing.


Image of the Flame Nebula courtesy of NASA