But tonight I gave a talk that began with the reading of Bible verses I selected, read from the pulpit in Asbury Seminaries Chapel. My brief talk was meant to contextualize our place as humans in the cosmos. Aiming for just 15 minutes, it is quite short, after after receiving a few requests via twitter, I’m going to post it here.

Please, please, don’t flame. Please.

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Hubble Ultra Deep Field [credit: NASA / STScI

Genesis 1:1-5
1 In the beginning God created the heavens and the earth. 2 Now the earth was [a] formless and empty, darkness was over the surface of the deep, and the Spirit of God was hovering over the waters. 3 And God said, “Let there be light,” and there was light. 4 God saw that the light was good, and He separated the light from the darkness. 5 God called the light “day,” and the darkness he called “night.” And there was evening, and there was morning—the first day.

John 1:1-5
1In the beginning was the Word, and the Word was with God, and the Word was God. 2 He was with God in the beginning. 3Through him all things were made; without him nothing was made that has been made. 4In him was life, and that life was the light of men. 5The light shines in the darkness, but the darkness has not understood[a] it.

Colossians 1: 16-17
16 For by him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things were created by him and for him. 17He is before all things, and in him all things hold together.

Romans 1:20
20 For since the creation of the world God’s invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from what has been made, so that men are without excuse.

Good Evening. I have to admit this was perhaps the hardest 1500 words or so I have ever prepared. I am a Christian, and I am a scientist, and most days I find myself dancing a careful dance where I try to avoid verbal bullets from atheist scientists and Christian young earthers. I have learned how to speak safely and when to speak unsafely to scientists, but this is my first time speaking before Theologians. I don’t know how far out of your comfort zone astronomy may take some of you. No matter what ideas you come to this conference with, I’d ask you to open your mind to learn new ideas, and in the breadth and magnificence of this universe which cosmology allows us to understand, find God in what is clearly seen.

Here on the surface of the Earth it is easy to see our universe as small and understood. Each year the seasons tick past in explainable ways, and 400 years after Kepler, the motion of the planets is just something we take for granted. Solar eclipses no longer make people tremble as the Asseryians trembled before the 763BC eclipse of Amos 8:9. Instead eclipses are just a roughly twice a year things that thousands of people turn into vacations.

From the surface of the Earth, it is easy to feel safe, and in control because we have the knowledge to understand the universe.

We have science to explain the supernovae, the comets, the ever twinkle and gleam in the sky.

But we are small, and life is fragile in this vast universe, and there are more things in heaven and earth waiting to be discovered than are dreamt of in our sciences.

Our human minds struggles to grasp at the scale of our universe. Any number over a million is simply large, and in discussing the cosmos, we discuss the billions and billions of galaxies, the billions and billions of stars, and distances so vaste that light has not yet had time to travel from most distant galaxies we see in the north to the most distant galaxies we see in our Southern skies.

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Saturn with Earth tucked in the Rings (left side, small blue dot) [credit: NASA / Cassini

Carl Sagan referred to the earth as Pale Blue Dot and in this image taken by the Cassini space probe, we can see the distant Earth in its smallness. Sagan wrote of our world, “Look again at that dot. That’s here, that’s home, that’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, … every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every ‘superstar,’ every ‘supreme leader,’ every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.”

Not only do we struggle to grasp at our smallness, but we also struggle to understand our place in time.

Our planet is a transitory thing. Formed roughly 4.5 billion years ago, it will be able to support life for only another 50 million years before the Sun’s slow increase in temperature makes life intolerable on Earth. In roughly 5 billion years our Earth will be destroyed entirely as our Sun bloats into a red giant and either consumes the planet or simply broils it with intense solar winds. We live in the twilight years of our world, and time is ticking.

But our planet is just part of a cycle.

We live on a rocky world orbiting a star that is rich in heavy elements. If you shine sunlight through the most amazing of prisms to make a rainbow, you will be able to single out dark stripes mixed in the light, many of which arise from Iron, Titanium, and other metallic atoms in the sun’s atmosphere.

To get at this richness of atomic diversity, our universe had to be created, and generations of stars had to live and die, all before our own Sun could be born.

When our universe formed, 13.7 billion years ago, it was pure energy – pure light. Within the first fractions of a second, that energy began to solidify into particles. Mass and Energy are just two faces of the same thing, and as the universe cooled, the mass divided from the light. At first there was matter and anti-matter, but through the miracle of asymmetry, for every 1 billion anti-matter particles there was a billion and 1 matter particles. The particles collided – they destroyed one another, and they left behind matter. And that matter, at that moment, and for almost the next 3 minutes, was as hot and as dense as the center of a star and nuclear fusion was able to take place. Protons combined. Neutrons were created. Hydrogen nuclei grew into deuterium, which in turn fused to helium and trace amounts of lithium and beryllium. Our theories tell us the ratios of these reactions, and when we look out at the oldest stars, we find the correct fractions fossilized in the elemental abundances of these ancient stars’ light. This is just one of many lines of evidence proving the big bang.

After the first 3 minutes, nuclear reactions shut off, but the universe was still too hot for neutral atoms to form. Everything was an opaque mash of nuclei and electrons and light, colliding. It stayed too hot, and it stayed opaque for nearly 300,000 years, but then one day it cooled enough that the electrons could bond with the atomic nuclei, and when that happened the light was released. Today we see this escaping light as the cosmic microwave background.

The cosmic microwave background demarks the point beyond which we can never observe. It is like the barrier beyond which your headlamp just can’t reach when scuba diving, or that place in the fog your candle cannot illuminate because it’s just to far away. Our universe, within this shell, is 93 billion light years across, but what we can see is likely no more than a few percent of the whole. But it is all the universe we will ever know.

And after the light separated from the atoms, our universe slowly cooled and expanded some more, but now structures began to form. It was only about 30 million years after the big bang that we believe the first stars lit up the then dark universe. The first stars lit up, the largest of them living and dying in the briefed million or so years. When these first stars died, they rained heavy elements on the gas and dust that was preparing to form future generations.

That stars could form is another miracle of our universe. There is no reason we can identify that the density had to be just right for stars. It could have been denser – and everything could have collapsed straight into black holes. It could have been less dense, and no stars would ever have formed. But it was neither of these things. The universe was just right to support stars, and those stars embedded in the darkness are what allowed life here to exist today.

We live on just one small pale blue dot orbiting a metal rich star. We exist because matter and anti matter were formed in unequal parts. We exist because the universe’s density was just right. We exist, because other stars formed, created heavy elements, and died, distributing the elements back into space to form our world and others.

And most amazingly of all, we live in a universe that is at once something we can learn to understand and something that is beyond our imagining.

Every day we are finding new things that defy our theories and force us to expand our ideas – We now know 26% of the universe is made of dark matter – a material like nothing experienced here on earth – and 70% of the universe is contained in dark energy – something we know so little about all we can really do is say we have a name for this rather large blank are in our scientific understanding. And every day we discover new planets in places we never imaged. New galaxies. New types of objects – all things we would have never imagined in our wildest science fiction.

We have been placed in a wonderful universe that is like a palace we have been allowed to explore. The rooms are many, and we can each find our own corner to ask our own questions concerning this creation.

But living in a universe with an amazing underlying physics that guides its evolution, does not preclude free will, or the occasional needed intervention. While A may lead to B it does necassarily dictate 200 years from now we will have D, E, and F occur. We live in a universe not dictated my certain outcomes, but rather one guided by probabilities, and in each possibility there is a chance for the future to be changed, either through the batting of a butterflys wing, through our own decisions, or through the intervention of a greater power – Our God – even if it is just a small voice in the dark reminding us that even in science we should have faith and believe while we look up and explore this amazing universe we live within.

Please don’t flame. Posting this was hard, but it was something people asked to read.

Gravity Probe B orbits earth, captured in its gravity well

Sometimes analogies just feel right. For instance, “as hard to find as a needle in a hay stack” is often a good way to describe trying to find a needed quote in a half-remembered book. The mental image and the actual task just fit. In physics, I sometimes feel like the hardest part is finding the perfect analogy that will make it possible for everyone in the class to visualize the concept I’m trying to explain. In the case of gravity, Einstein kindly provided the needed analogy. He said the way we need to think of gravity is as a divot in the 4-dimensional space-time reality, where orbiting objects simply roll around the inside of the well, like bicylcists racing around the sides of a velodrome. Ok, so maybe that analogy is a bit more challenging to follow. Nonetheless, in all its complexity this analogy points us toward one idea: If space were a surface instead of volume, the surface would curve down toward anything with mass, and it would curve more for high mass objects than low mass objects (and black holes may just tear a hole in that surface).

In this visualization of the universe, objects’ masses define the shape of space, and acceleration of a small object (like a space craft) toward and deceleration away from a larger object (like a planet) is just a side effect of the small object rolling “downhill” into a gravity well and “uphill” out of the gravity well.

This image of space leads somewhat naturally to a series of complex ideas. For instance, if you suddenly remove a mass from or change a mass on the space-time surface, you can imagine the surface rebounding, with waves moving across the surface as a result of this sudden rebound. We believe this is part of the reality of gravitational waves, which have there definition in much more complicated mathematics. Frame dragging, as well, can be imagined as a rotating body catching at space, a swirling it about itself, forcing a beam of light trying to return to its origins to fly farther to go in one direction than the other. You can think of this like a person trying to run around an in-motion merry-go-round; race in the direction of motion and you are partially carried to your point of origins, but if you go against the flow of carousel horses you’ll have to go an added distance as the the merry-go-round tries to carry you the wrong way from where you want to go.

The next consequence is light gets reddened as it climbs out of the gravity well. You can explain this as losing energy (getting redder) as the light fights its way out against gravity, or if you want to think geometrically, this is just like a person climbing up a hill covers a larger distance, using more energy on foot, if they walk 1 mile as the crows flied than that 1 mile the crow flew. Light changes colour because it transverses hills.

From gravity waves, to frame dragging, and all the way out to the reddening of light rising out of a gravity well, this geometric idea of space is the one my brain understands, and it is the one that Einstein geometrically built for us.

This plays against the ideal of gravitons carrying the news “This way lies a mass, come be attracted” as they fly out from the stars and the planets reminding everything to orbit politely.

Now I have to admit, I don’t read theoretical gravity papers for fun on a regular basis. Life is short, and the numbers of papers coming out each week is in the hundreds. I may have missed something, but one thing I haven’t seen yet is a way that allows one to understand gravity as geometry while still invoking gravitons as the force communicators. It is my hope that either this happens or someone finds a way to detect gravitons soon. Gravitons are massless and so weak that right now we just don’t have a way to detect them. This means we can’t prove they are there. We also can’t mathematically build a theory that unites Quantum Mechanics – the science behind a lot of particle physics – with gravity. As an observational astronomer, I have to admit, I have a certain hunger for someone to explain to me why gravity can’t be the shape of space and time while everything else is particle based.

Hmmm, maybe I should hunt a theorist and ply them with chocolate. Or coffee. Or something stronger.

But for now I split my head between two ideas – particles and geometry – while I dream of a unifying analogy.

This is Ethan from Starts With A Bang! over here at Pamela’s blog, Star Stryder. I was pretty pleased that she came across a couple of press releases and actually thought of me… so let’s have at it! First off, what do the press releases say?

Dr HongSheng Zhao, of the University’s School of Physics and Astronomy, has shown that the puzzling dark matter and its counterpart dark energy may be more closely linked than was previously thought.
…
Dr Zhao reports that, “Dark energy has already revealed its presence by masking as dark matter 60 years ago if we accept that dark matter and dark energy are linked phenomena that share a common origin.”

Really? Well, this is a possibility, but this is certainly not necessarily true. We do know that about 4% of the stuff in the universe is normal matter: what we know as protons, neutrons, and electrons. But although you need dark matter to explain things like

• the internal velocities in galaxies and galaxy clusters,
• the gravitational lensing data, and
• the formation of structure in the universe,

dark energy is only needed to explain why the cosmic expansion rate is larger than it would be if the Universe were made exclusively of matter. They could be related, but they aren’t necessarily. Dark matter affects how gravitational collapse happens, but dark energy affects how things move apart on much larger scales.

But the press release goes on, and contends:

However, the Universe might be absent of dark-matter particles at all. The findings of Dr Zhao are also compatible with an interpretation of the dark component as a modification of the law of gravity rather than particles or energy.

Oh! Well now I know what they’re talking about, and it’s incompatible with the data. Let’s walk you through it, but first, so you know where I’m coming from, let me link you to the scientific article that reviews Dr. Zhao’s work, as well as his works that were published in the Physical Review and the Astrophysical Journal.

Basically, people don’t like the idea that we only understand 4% of the Universe, and that 96% of the energy in the Universe is made up of stuff (dark matter and dark energy) that we don’t understand at all. So what some scientists attempt to do is to modify the laws of gravity that we know, General Relativity, into something that can mimic the effects of dark matter and dark energy without actually requiring them. But we do need dark matter, and here’s why:

Angus et al. [of which Zhao is one of the coauthors] found that the lensing peaks of the Bullet Cluster could be explained by adding neutrinos in a TeVeS-like modified gravity; the phase space density of neutrinos at the lensing peaks requires 2eV mass to in order not to violate exclusion principle for fermions.

Putting the language issues aside, he’s saying that even if you modify gravity in the best way possible for the Bullet Cluster, you still need 2eV mass neutrinos. From this page, we know that’s more massive than neutrinos are allowed to be. So you still need to add an extra, dark, non-interacting mass to this theory of modified gravity. Know what we call that? Dark Matter!

So the answer to my question is, emphatically, we still need dark matter to be consistent with all of the observations we make. Could dark matter be related to dark energy? Sure, but there’s no evidence that it is. People have also speculated that dark energy is related to neutrinos, axions (a dark matter candidate), and inflation. But at this point, all of it, including this press release, is still just speculation.

I’m happy that people are thinking about it, because these are two of the most interesting topics out there: figuring out what makes the Universe form structure and expand as it does. And yet, the observational evidence for dark matter is overwhelming, even if it still has trouble explaining all of the galactic rotation curves. There’s a lot we still have to learn, but throwing dark matter away isn’t going to be the answer.

In a really cool press release that I got yesterday but couldn’t share (silly embargoes), it was announced that observations of distant galaxies support the idea that Dark Energy is most likely a real force or field that we don’t yet understand (as opposed to it being a side effect of us not understanding gravity – it looks like we really do understand gravity). (image left of galaxy spectra from VIRMOS)

Now, at first look, this doesn’t sound that specific our exciting. In fact, the vagueness of our understanding of Dark Energy (and Dark Matter, but this isn’t a post about Dark Matter), lead many people to randomly announce (often in email) that they “don’t believe in Dark Energy.” I even had one of my colleagues last week tell me that he doesn’t believe in Dark Energy (or Dark Matter, which I’m still not talking about). If astronomers can’t convince random physicists (who will admit they haven’t read any of the findings in the past couple years) that Dark Energy is real, how can we convince the general population.

Admittedly, dark energy is something that we can’t see, can’t taste, can’t touch, can’t measure directly, and can’t even precisely mathematically describe. This makes it somewhat hard to sell as real (although it doesn’t appear to have been to hard a sell for the boogie monster, tooth fairy, and snow yeti). So, this raises the question, how can we know Dark Energy exists?

Well, just like the invisible men and invisible women of fiction are detectable through their footprints (a push on the ground), are detectable from the lamps and other furniture they throw at more visible heroes and villains (pulls on objects), and are detectable through the punches they throw (a very definite push), dark energy is also detectable through the push it exerts on the universe.

Dark energy was first detected in 1998 by supernovae observing teams who were working to measure how the expansion rate of the universe has changed over the 13.7 billion years the universe has been around. They expected that the gravitational mass of everything in the universe on everything else would cause a breaking of the expansion. What they found instead was that some mysterious force / field / extra term on gravity / etc is pushing the universe apart and accelerating the expansion. Since this weirdness didn’t have a name, and the name dark energy wasn’t already in use, the weirdness was named Dark Energy.

Since that fateful discovery, people have been working to figure out if dark energy has always been around, if its push has always been the same. Using supernovae, astronomers were able to figure out that dark energy has been around at least as far back as they can go with supernovae. What they haven’t been able to figure out is if it was something related to us not understanding gravity (a constant, back of the mind concern), or if it real is some sort of field effect that just sort of permeates all of space.

And not knowing makes good astronomers apply for telescope time so these questions can be answered.

In a paper published in Nature today, 51 astronomers led by Luigi Guzzo announced that studies looking at a large selection of galaxies in clusters at high and low redshifts (from the VIMOS VLT Deep Survey and the archived 2dF Galaxy Redshift Survey) have found that the motions of galaxies in clusters at high redshifts indicate that 1) we understand gravity, and 2) dark energy has nothing to do with gravity.

Unfortunately, the press release was a little vague, and perhaps even a little contradictory, and I don’t have a subscription to Nature. Here is what it says:

Within current uncertainties, the measurement of this effect provides an independent indication of the need for an unknown extra energy ingredient in the ‘cosmic soup’, supporting the simplest form of dark energy, the so-called cosmological constant, introduced originally by Albert Einstein. The large uncertainties do not yet exclude the other scenarios, though.

“We have also shown that by extending our measurements over volumes about ten times larger than the VVDS, this technique should be able to tell us whether cosmic acceleration originates from a dark energy component of exotic origin or requires a modification of the laws of gravity,” said Guzzo.

I read this to say, they see evidence of dark energy at high redshifts, it isn’t possible to discard dark energy as not existing, it looks like dark energy isn’t a problem with gravity, but there are error bars, and Guzzo thinks continued analysis will make the error bars tiny enough to end this debate.

It’s a start. And it means dark energy is real.

So stop sending me email

Some background… Many cosmologists believe our universe is one of many parallel or branching universes.  These universe’s, if these theories are right, are boiling and seething side-by-side, and (if these theories are correct) these parallel multiverses may periodically merge like two soap bubbles meeting in the wind. It may, if these theories are correct, be possible that one edge of our universe is rapidly getting eaten away by another cannibalistic universe. (Go read this article by Andrei Linde to learn more. Additional links are on his website.)

Those are the theories. Observationally, until the big rip comes are way, we have no way of knowing if they’re true.

And, the New Scientist article seemed to indicate that we might have found that proof in the from of a giant void. (I talked about the void here). The proof? Well, I couldn’t find a peer reviewed journal article or any related science papers, so I’m a little sketchy on what the proof is other than there is a volume of space with no radio galaxies superimposed in front of a particularly cool section of the CMB.

There are also giant galaxy clusters out there and hot areas of the CMB. I’m not sure any of the big things are as big as the void, but dense things tend to collapse while empty things tend to appear to grow as the things around them collapse. Think of it this way: Imagine you have a crowded show room of people and you drop in 5 people who just finished cleaning barns, eating beans, and haven’t yet showered. An initial small area of nothing – a void – will form around each of these people, but it won’t grow since their smell probably is only noticable within a small radius. Now if you drop in 5 movie stars willing to sign autographs and have their pictures taken, then you’ll see a collapse as people crowd around the movie stars, and one side of effect of that collapse is those voids around our tired smelly people (who’ve opted to just plunk down on the floor and wait out the madness rather than to mob the movie stars) seem to grow. The smelly people aren’t doing a better job pushing people away – they didn’t get smellier – but rather the movie stars attracted all the mass to them making the voids seem to grow.

Until we have optical deep images of the void and spectra to map out any non-radio galaxies or other objects (like gas clouds) in the void, I can’t put much significance on the “It’s the most giant empty thing no one ever imagined could exist” hype. Yes, it is cool. Yes, it needs follow up time to understand. But, shouldn’t there always be 1 spot on the sky that is labled “Here be the lowest density of stuff?”

So, rant about the void hype aside, what about the “Its another universe” hype?

Personally, the idea that another universe merging with our own appearing as nothing more than an empty patch strikes me as rather depressing. No fireworks. No gamma rays. No high energy, low energy, or any energy anything – just a bubble of nothing. I’m not a theoretical cosmologist, but I can’t imagine how to colliding universes, with potentially different physical parameters, could collide and not create cause some sort of event at the surface of merger.

I wish I could find a scientific paper addressing this, but I couldn’t. And New Scientist is read by more people than any science journal (and maybe by more people than all the English astronomy only journals combined). So… What people are going to end up learning is our universe might be getting consumed. And some of them will freak out. And some of them will decide this is another example of scientists scaring people for not reason. And I really wish this type of hype wasn’t something I know will eventually lead to some student saying “Isn’t our universe getting sucked into a giant void?” one day.

Maybe it’s getting sucked into a void. Maybe. But I don’t think it’s getting sucked into that particular void.  Give it a couple years – that’s how long I think it will take to get the telescope time needed to start to understand the void. Once the data is in, please feel free to built as big an observationally based theory as you like.

Thought questions like this have pretty much always been around, and trace back at a certain level to the old standby, if a tree falls in a forest and no one is there to hear it, does it still make a sound? If it weren’t for some annoying observables in quantum mechanics, these questions could be ignored by observational astronomers like myself, and pushed over to the philosophers and theologians that occupy other buildings on my campus.

Unfortunately, in quantum mechanics it has been observed that observing a metastable system can reset the clock that probabilistically determines when a decay may happen. Think of it this way, if something is hanging out in a given state (someone sitting upright and awake in an office chair in the a cube in the Dilbert universe), there is a certain expected time period that they can be in that state before something happens (like that person falling asleep). Now, if the something in the given state is observed (for instance if the boss sticks his head in our person’s cube and says something), the time that will likely pass before a state change occurs will get reset (if the person typically nods off after reading brainless reports for 2 hours, and the boss comes in 1.5 hours into report reading, the person will read for another 2 hours – a total of 3.5 hours – before they nod off).

With our universe, it is believed that everything started out at one high energy, back during the big bang, and during the epoch of inflation the universe decayed to a lower energy state. It is possible, according to some theories, that the universe is still decaying, and the overall energy of the universe will change over time, possibly destroying everything we know in the process as it jumps between discrete states. This potential decay is a quantum mechanical process, and how it does or doesn’t occur might be effected by us, or aliens, or dogs, or some interstellar gaseous intelligence observing dark energy. It’s possible. But it’s also possible nothing will happen, and the current energy state is stable, and we will just, as a universe, expand forever.

The fate of the universe is an unobservable thing. We can’t see into the future to get data. There are a lot of “what if”s hidden in the mathematics of cosmology. There are a lot of “just maybe”s coming out of quantum mechanics. A scientist would be remiss not to address all possibilities – it’s our job to doubt and question and explore the improbable. But, sometimes our gedanken wanderings end up chasing white bronco not driven by OJ Simpson, but rather by some genetic doppleganger that was the 1 in a trillion impossible second match the bloody glove. I don’t think that doppleganger exists, and I don’t think that studying the heavens will change their future.

After all, Schrodinger’s cat was a perfectly good witness to its own death.

The hype of the New Scientist story was reckless reporting designed to excite and tantalize. Remarkable, it may have lead the authors of the paper this was all based on to re-write their paper.

In the first version of their paper, they write (hat tip to Galactic Interactions):

If observations of quantum mechanical systems reset their clocks, which has been observed for laboratory systems, then by measuring the existence dark energy in our own universe have we reset the quantum mechanical configuration of our own universe so that late time will never be relevant? Put another way, can internal observations of the state of a metastable universe affect its longevity?

In a later version the instead say:

 Have we ensured, by measuring the existence of dark energy in our own universe, that th quantum mechanical configuration of our own universe is such that late time decay is not relevant? Put another way, what can internal observations of the state of a metastable universe say about its longevity?

Yes, our observations could be changing things, but we can’t say for certain, and we can’t say how they are effecting things. And this doesn’t mean we shouldn’t be observing. This isn’t some cosmic game of “I Spy, the Universe dies.” And even if our observation does something to the universe, that doesn’t mean we should stop observing. Even though I believe life is rare, the universe is a big enough place that I feel confident saying we aren’t the only ones observing dark matter (we just may be the only ones in our galaxy doing it), and our observations are just a small drop in the cosmic observational bucket.

So, go out and observe. Increase knowledge and crush the ability of over hyped reporting to get attention.

Transcript: This is a talk I originally prepared to present as part of the 2206-2007 convocation series at Illinois College. Since then I have given it before several other audiences, and with every presentation I’ve had more people ask, will this be online. Finally, I can saw yes. Here’s the link. Please enjoy.

In today’s crazy world, it is easy to get lost in the details of our overly busy lives. There are projects, deadlines, business meetings and family meetings all demanding our attention. I suspect at least some of your employers have led you to believe their project should be the most important thing in your life right now. And I suspect that at least one person in your family has led you to believe that being at their home on time for some particular family gathering is the most important thing you can do this month. With all these specific day-to-day details demanding attention, it is hard to find a moment to step back and consider the big picture.

Especially when the big picture encompasses the entire universe; past and present, and possibly even parallel.

Right now, I invite you to set aside the details of today, and consider instead the details of the first day, and the implications those details have in creating the universe we live in.

Science in the 20th century has made huge strides in understanding the science of our universe.

We went from not understanding how physical traits like eye color are passed from parent to child, to James Watson and Francis Cricks 1953 discovery of DNA to the 2000 completion of the first draft of the Human Genome project, which is mapping the entire genetic structure of the 25,000 some odd genes that make up each of us.

We went from seeing the entire universe as a continuous distribution of stars and nebulae; to Edwin Hubble’s 1929 discovery that the Andromeda Nebula is actually a separate galaxy apart from our own; to the 1989 realization by Margaret Geller and John Huchra that we live in a universe of structure, with galaxies tracing out voids and filaments and clustering in some cases by the 1000s in giant super clusters.

We went from viewing the universe as a stationary place – where everything was as it always had been and always would be – a Universe that Einstein held in place in 1915 when he published his General Theory of Relativity with a cosmological constant – to seeing Hubble’s late 1929 realization that the universe is expanding, to the 1998 discovery that the universe is not just expanding but accelerating apart.

From the DNA of life to the cosmological expansion of the universe, we have found rules to describe our place in the cosmos. But the rules that describe our place, can’t answer the more fundamental questions of why does our universe exist and why is our universe the way that it is.

Today, 21st century science struggles with these more fundamental questions. Physics as we know it does not dictate our universe should be just as it is. Rather, many other possibilities are possible and perhaps even more probable. But we are here, and this has consequences on how we must view our universe, and on what forces might make the improbable possible. It is the improbability of our place in space, and the consequences of our reality that I want to discuss today.

Since this is a discussion of science, we need rules to govern our thinking and our logic. Without rules, it is possible for anyone to say anything and say it is true, just because that anything fits into their own personal set of beliefs. Science, starts with the premise that it is possible to run experiments and make observations that tell us about the universe around us. Any theory I develop to explain the universe must conform to past experimental results and observations, and a good theory can be used to predict the outcome of future experiments and observations.

Put simply, as a scientist, when I observe that a tossed ball goes up and comes back down, I believe that I am observing a real phenomenon. Now, it is possible for me to theorize that any object thrown up into the air will also go up and come back down, and to predict that if any of you toss a ball up into the air, you too will observe the ball go up and come back down.

So far so good, I have a theory, it fits past observations, and it makes concrete predictions. As a scientist however, I also have to be willing to say my theory is wrong if it can be disproved experimentally.

This means, if I observe an object get thrown into the air and not come back down — for instance a space probe getting thrown into space by a giant rocket, that rather than falling back to Earth goes off to explore Mars – then I have to modify my theory to incorporate the new observations. Now, my theory would have to say, any object thrown upward will come back down unless its velocity is greater than the escape velocity needed to get away from Earth’s gravity. Such an object will go up, and keep going until it encounters the gravity of something else. Ideas build and grow, and incorporate into themselves the results of each new experiments. I started with my observations of my ball, but then incorporated my observations of a Mars probe.

In the history of science, Newton’s theory of gravity grew into Einstein’s General Theory of Relativity, which someday will probably grow a new name as the theory it self grows to include results pertaining to quantum mechanics and the physics of black holes.

In science, we also have the basic rule that theories are as valid on the other side of the universe as they are here in this room. This means that any theory of tossing balls here on Earth will also be valid on the other side of the cosmos, where some green handed individual might perform the same experiments I perform. Science is one of the few languages that isn’t rooted in culture or even planet orgins. The physics here is, simply, the same as the physics everywhere.

Along with the rules being the same everywhere, science also assumes that if you look at a large enough chunk of space, the universe is the same everywhere. Our neighborhood of space, if we define it large enough, is the same as every other neighborhood, with the demographics and the same evolution. No neighborhood is special. Put scientifically, using really big words, this basic tenet, dubbed the Cosmological Principle, states that the universe is homogeneous and isotropic.

We also have one more rule that tries to govern us, and that’s the principle of mediocrity. This is the rule that we don’t live in a special place, a special time, or a special anything else. There should never be any result that rests on us being at just the right place and moment in space and time. In considering this rule you again have to think big. The time we live in on the planet Earth, is special. We live during the halceone extinction, and have the privilege of watching global warming. We also live during a special time when our sun isn’t too big or too cold or to hot, but is just right for life. When considering the principle of mediocrity you have to look at the entire age of the universe and expance of the cosmos and say, our Sun isn’t special, our galaxy isn’t special, our lifetime, against all the other 60 to 100 year blocks of time isn’t anything great. In the local scheme, we live in far too interesting a time, but cosmically our place is space isn’t anything extraordinary.

So there you have it: everything is the same everywhere and none is special. We simple live to observe the same stuff you can observe anywhere, and we use those perfectly boring observations to built theories that, if they are scientific, are able to predict what future observations will see.

With these basic ideas, I have the intellectual tools I need to explore the universe, and what a beautiful universe it is. Today’s modern story of Genesis, starts with a Big Bang that marked the beginning of time and space. From a nothing that some describe as a quantum foam fluctuation, there emerged energy that would condense into the universe we now occupy. For a brief moment, all the atoms that make up you and me and the entire universe were condensed into a single speck of pure energy.

As that early, energy filled universe expanded, it went through a period of exponential growth that is referred to as inflation. During this period, the space itself expanded so rapidly that two points would appear to separate faster than the speed of light. Now, don’t misunderstand this. The objects didn’t actually move faster than the speed of light, but the actual space grew, as though the entire universe was a piece of graph paper that kept getting run through a Xerox machine set on enlarge.

In this situation, the actual place on the universe that a given point or three might be located, would stay constant with time, but the universe itself expanded, making the space between those spaces bigger, making it appear that the points were moving apart. The apparent velocities, as the grid carried the points with it from a confined space to an enlarged space, could have seemed to be as high as several times the speed of light, but appearances aren’t always reflections of reality, and the points in space didn’t actually move on the grid of space time. The grid itself simply enlargeded.

Had the inflation gone on longer or pushed things farther apart than it did, the material in the universe would have been spread out too much and become too smooth for stars and galaxies to later condense. Had inflation not spread out matter as much as it did, it might have clumped up so much that everything collapsed back together, producing a big crunch shortly after the big bang. Physics, as we know it, doesn’t require inflation to work the way it did, but the universe we live in requires there to have been inflation in order for us to exist.

As the epoch of inflation ended, the universe cooled and matter began to condense. From Einstein’s famous E=mc^2 we know that mass is just another face to energy, and that the two can transform from one to the other. As our universe expanded, it cooled, and matter was able to solidify out of the energy.

The catch is that when energy changes into matter it should also produce anti-matter. For every proton – the key ingredient in atoms – there should also be an anti-proton. For every electron there should be a positron. The reason I say this is a catch is very simple – as you and I look around this room we don’t see anyone made of anti-matter. As astronomers look out across the sky, we do not find anti-matter stars or galaxies. In fact, while anti-particles are observed, they are transitory things, which quickly annihilate as they collide with regular matter. If, at the beginning of the universe, matter had condensed into equal parts matter and anti-matter, than no matter should exist today.

But, we do have matter. We exist. Observationally, we know that somehow, for every 10 billion anti-matter particles that formed, there must have been 10 billion and 1 particles of regular matter. When the 10 billion matter and anti-matter particles combined they left behind 1 particle of matter and a lot of light. This fine tuning created a universe that was just right for us to be able to be in this room, but that is mathematically ugly, requiring asymmetries in the matter and anti-matter. These are asymmetries that theorists can’t make fall naturally out of any equations. It seems the universe simple was made just so.

And it made it just so in the flash of an eye. Within a second, all this was over. Inflation was over. The self-annihilation of matter on anti-matter was over. And then, from about 100 seconds after the big bang until 3 minutes after the Big Bang, the entire universe did its best imitation of the inside of a star. Proton’s collided together with such high velocities that nuclear reactions built hydrogen into helium, and a little bit of lithium and beryllium. The results of this early, Big Bang Nucleosynthesis is still visible in the ingredient lists of the oldest stars. After the Big Bang the universe was 25 percent He, and little bit of deuterium, a heavy form of Hydrogen, and it contained trace amounts of Lithium.

After those first three minutes, it was too cool for nuclear reactions to continue, but too hot for much of anything else to occur. For nearly 400,000 years electrons, atomic nuclei, and radiation formed a thermally interacting soup that simple expanded and cooled, but didn’t do much else. Finally, around year 380,000 the universe cooled to a point where normal atoms could form, and the electrons bonded with the nuclei, and the radiation was free to fly away.

That radiation, the radiation created when the matter and the antimatter collided, was set free when electrons bonded with nuclei, and it continues to permeate all of space today and we observe it in the form of the cosmic microwave background. Slight temperature differences in the universe at the moment of recombination, reflect slight changes in density from one part to another. And when I say slight I mean slight – the variations seen in this temperature map represent differences of just one part in 100,000.

Today, the Cosmic Microwave Background has a temperature of 2.725 degrees above absolute zero with fluctuations of just 0.000018 degrees.

These small variations would eventually collapse into the large-scale structures – the galaxies, and galaxy clusters – of today’s universe, but that would take time. The largest structures formed first, creating the scaffolding into which all the matter would flow. Within these structures the first generation of stars formed as material streamed into forming galaxies. And at the junctions of these structures super clusters formed at the location of the largest temperature fluctuations. Today we can see the distribution of temperature fluctuations reflected in the distribution of matter in space.

Initially, the neutral universe was a dark place. It stayed dark for almost 400 million years while the material slowly collapsed. For almost 400 million years the universe consisted entirely of neutral gas that didn’t create light and in fact would have been opaque to any light that might have existed. Than finally, one day the first stars were born and their light cleared the opaque gas, making the universe transparent. At that moment the just forming galaxies lit up the early universe. In the billions of years since then, stars have continued to be born, and galaxies have continued to grow, and today we can trace out the evolution of these objects using telescopes as time machines.

Because light travels at a finite speed, it takes time for information to travel from one object to another. Over small distances, such as the distance from me to any of you, this time is unnoticable. I speak, and faster than I can blink, you see my lips move if we were in the same room. Still, in all truth, you can never see me in the moment, and I can never see you as you appear at the exact now that I say now. The light always must take some time to travel, even if it is sometimes an unimaginably short time.

As distances grow, however, the time it takes light to travel becomes meaningful. When reporters try and report live from overseas locations, we can see the lag introduced as a question travels from the american studios, up to a satellite, across to a different satellite and then back down to the reporter, only to have to return again. As we move farther and farther and farther away, this time grows. When we look at the Sun, we see it as it appeared 8 minutes ago. Jupiter is seen as it was 40 minutes ago. Scientists sending probes to distant planets must program the robotic explorers to act autonomously because it isn’t possible, with even a few minutes of lag, to drive a space ship like a remote control car.

And consider this fact: Light from our neighboring galaxy, Andromeda, takes more than 2.36 million years to reach us. This means that we see Andromeda as it was when early humans were just starting to walk the Earth.

As we look at the most distant objects, we are able to look back at our universe’s infancy. What we find is a fascinating story of gravity and some mysterious expansion causing force playing a game of tug-a-war with our expansion rate. In the early days of the universe, matter dominated everything, and the gravitational force of everything on everything else worked to slow the expansion left over from the original Big Bang. Until recently, it was believed that our universe might someday reverse directions, and collapse in on itself, or that perhaps it would slowly coast outward at ever slowing rates that might or might not eventually hit zero.

But, all because you think something is true doesn’t make it true. In 1998, the entire astronomical community had to rethink how we view the universe when it was discovered that the rate of the universe’s expansion began to accelerate 5-6 billion years ago.

Using type 1a supernova, a type of exploding stars that give off set amounts of light, astronomers can measure distances out to the far corners of the universe the same way that you estimate the distance to an oncoming car at night. The light from any standard light source appears more or less bright depending on the distance to the light. If you are standing in the middle of the road and see really bright headlights you might correctly realize you’re about to get hurt, while if you see really faint headlights, you might decide you can pause to pick up a penny in the road. Your brain is automatically doing math, and astronomers do that same math to figure out where supernovae of different brightnesses are located.

Once we know where and when a supernova is located, we can get at the expansion rate in their corners of time using the same technique that policemen use to measure the speed of your car. When a light is either moving or reflecting off a moving object, it gets shifted in color.

The color shift we observe is related to the direction of motion. As an object moves toward an observer, the light waves get squished together, appearing more blue. Conversely, light waves get spread apart, appearing more red, when an object moves away from an observer. Today, astronomers have distance and velocity information for dozens of supernovae spread all over the cosmos, and from this information we can plot the changing expansion rate of the universe.

From our plots, we know that roughly 5-6 billion years ago, the universe’s expansion began to accelerate. The culprit, the repulsive force, behind this acceleration is called Dark Energy. It’s always been there, affecting each cubic meter of space, and trying to push things apart, but it’s only in the modern universe, where the space between objects is vast, and the total volume of space is something much greater than vast, that Dark Energy has been able to become a major effect.

Each cubic meter of space has the same repulsive quality. As the universe continues to expand, each new square meter of space has the same repulsive quality, and the total amount of repulsion grows with the universe. As the universe expands, it will accelerate itself apart as an ever-growing proportion is made up of dark energy.

Think of it this way, when you first mix the ingredients for bread dough, the dough is dense, and every square centimeter is primarily made of flour. As the dough rises and is eventually baked into bread, each square centimeter consists more and more of air. Now imagine the dough could expand forever until each square centimeter consists of only 1 grain of flour, and all the rest of the space is air. In our own universe, the mass is getting spread out more and more each moment and dark energy fills in all the intervening spaces.

As best as anyone knows, dark energy arises from the vacuum of space. In this vast, seeming nothing, there is energy, and this energy constantly boils with particles that are forming and annihilating one another. Some of these particles, those that fall into the category of bosons, such as protons and neutrons, have a positive energy, and those that fall under the label fermions, like electrons, contribute a negative energy. Observationally, the total amount of dark energy seems to work out to an energy equivalent to roughly 3 protons per cubic meter.

This is a very small value – which is good, because if it were any larger the universe would have been shredded apart. Just an increase of a factor of 10 would have prevented our universe from forming stars, galaxies, planets, and life. This is called the big shred, and some strange coincidence of space and time saved us from that fate. The physics, as far as we know, doesn’t require dark energy to be so small, in fact, most theories predict that it should be 10 to the power of 120 times larger! Theory doesn’t even require dark energy to be positive. Because the universe happened to be set up with a positive dark energy of this roughly 3 protons per cubic meter and no larger we are able to exist.
And it is because of another magically just so number that we are able to understand dark energy and also be able to exist.

That other magic number is the the fine structure constant.

When we observe supernovae, we study the way they give off light in some colors and not in others. Every atom gives off it’s own specific set of colors. When you see a neon “Open” sign, you are seeing red light given off by excited neon gas. Blues come from argon, and purple from Xeon. These colors come from the energy transitions of electrons orbiting the proton neutron core within an atom.

Let’s consider for a moment the atom most required for human life – carbon. This atom consists of 6 protons, 6 neutrons, and 6 electrons. It is formed in stars like our own Sun, and can be found throughout the galaxy.

When we observe supernovae, we study the way they give off light in some colors and not in others. Every atom has its on characteristic energy levels that orbiting electrons are allowed to occupy. Light carries energy that corresponds to its color. When light of the wrong color collides with an atom, nothing happens, but when light of the right color comes in, for instance when light from the center of a supernova collides with matter surrounding the supernova, the light gets absorbed.

Atoms can also give off light. That red neon “Open” sign you see documents the energy drop of electrons within the gas.

Sometimes light is absorbed by atoms, and sometimes atoms give off light.

These absorptions and emissions lead to bright and dark bands in the spectra of the objects we observe, whether they be stars, nebulae, supernovae or galaxies. The exact fingerprint of these atoms is governed by quantum mechanics, and in the midst of a lot of elegant equations sits an experimentally determined fine structure constant.

The value of the fine structure constant isn’t defined by the physics. It just is. Along with determining fine divisions within the colors we see in neon signs, and in supernovae, the fine structure constant also defines how well the cathode tubes in old TV’s were able to form a picture, and it plays a role in the electromagnetic force between all charged particles. If its value changed, the properties of all atoms would change, and we probably would not exist to view supernovae and the expansion of the universe.

The list of things that appear to just be the way they are “just because” is an ever-growing list. One of the holy grails of science is that one underlying elegant equation that will explain everything; the fine structure constant, the amount of dark energy, the length of the inflation epoch, the proportion of matter to anti-matter… all these things and more we keep hoping will fall out of some magic perfect equation that elegantly sums up everything.

But we can’t find that theory.

Einstein spent his life searching for it. Hawking has looked. Every great cosmologist has asked, “Hmmm, what if…,” and they’ve come back with nothing certain. There is string theory – a mathematical model that attempts to unify all of the forces by assuming particles are multi-dimensional strings rather than point sources, but… There are perhaps 4 people in the world fully understand string theory, and there no one who has been able to come up with a way that we can either verify or falsify string theory. Without experimental testing, string theory can’t be considered science. It is just a pretty mathematical art form that might some day grow into making testable predictions. But, it’s just not there yet.

So for now, as I scientist, I find myself in a universe that has a lot of things that seem to be just so, just because. I also have this rule that states that I can not live in a special time, place, or special anything else. These two things seem to be contradiction. I could brush it off and say it’s a coincidence, don’t sweat it, but… But at a certain point, if the same person, or in this case the same universe, wins the lotto day after day after day, you have to wonder if something funny is going on.

And right now a lot of scientists are wondering how it is that so many things are so improbably just so.

It seems that there are three possibilities.

1) We could of course not really understand the universe. It could be there is some yet undiscovered underlying rule, some beautiful set of equations, that will dictate all the impossible coincidences must exist. This is the hole grail so many cosmologists seek.

2) Another possibility is there is force outside our universe, outside our space and time, that is dictating the constants of our cosmos. Perhaps there is a God, a watchmaker, a greater power tweaking our forces to make life possible. But, this possibility is beyond the testing of science. We don’t know how to verify or falsify it and, as scientists, we must set it aside as something beyond science.

3) The third possibility is to some the ugliest and to others the most elegant. This third theory says that our universe is just one of many and that our improbable reality is able to occur because every possible combination of constants exists somewhere in the multiverse of universes.

This third theory may or may not be testable. And this possibility, falls out of many different ideas.

There is the probability argument: In theory, if enough monkeys pound on typewriters for enough years, Hamlet will emerge, and it makes sense to say that if enough universes are allowed to exist, eventually life will emerge. But saying that something makes sense just isn’t enough.

Luckily, many scientists find more compelling ways to get at multiple universes.

According to Quantum Mechanics, the outcome of a quantum event doesn’t exist until it’s observed. This is the premise behind the Schodinger’s Cat thought experiment. The experiment goes something like this: You lock a cat in a sealed container. In the container with the cat is a Geiger Counter and a small bit of radioactive material. At any given moment each atom in the radioactive material has a certain probability of decaying. If, for instance, it’s a bit of 210Polonium, the half life is 138 days. This means that statistically, if you have a bunch of atoms of Polonium, half of them will decay within 138 days. The thing is, statistics doesn’t require half the atoms must decay. It could be that more decay or that less decay. It’s just a probability.

If I flip a coin a bunch of times, I should get heads half the time, but it doesn’t mean I will.
Now if my bunch of Polonium happens to add up to 138 atoms, statistics say that on any given day, I have a 50/50 probability of one atom decaying. So, imagine I have a cat in a box with 138 atoms of Polonium, and I have a Geiger counter to detect if any atoms actually decay. Just to make things interesting, I attach a vial of poison to the Geiger counter, such that if some atom decays, the Geiger counter will trigger and burst the poison, killing the cat.

According to Quantum Mechanics, the atoms each exist at every moment in both a decayed and a not decayed state. Only at that philosophically painful moment when the atoms are observered do the wave function collapse, and the atoms become absolutely decayed or absolutely not decayed. This means, until observed those atoms hover in the decayed/not decayed state and the cat hovers in both a state of alive and dead.

In all reality, the cat is a perfectly good observer of its own death. But still, the atom could be decayed and not decayed the Geiger counter or something else cames along to interact with its wave function and observe the outcome.

Radioactive decay isn’t the only weirdly probabilistic thing we observe. For instance, if I have the world’s most pathetic laser and it gives off just 1 photon at a time, and I point my pathetic laser at a series of slits, the photons will go through and scatter out onto a screen on the far side of the slit. If I keep watching where the photons have landed for a period of time, they will build up a pattern that just happens to be identical to the interference pattern that you get if a bunch of photons from a very bright source all going through the slits at once. Thus, for several odd quantum mechanics reason, photons have some weird probabilistic way going through slits as waves and interacting in probabilistic ways. While no one can predict where any one photon will land, using quantum mechanics we can predict the pattern lots of photons will build up.

But why should any one photon do one thing, when in the exact same situation another photon does something totally different?

But why should any one photon do one thing, when in the exact same situation another photon does something totally different? According to what is called the Oxford Interpretation or the Many World’s Interpretation, each photon actually takes every single different option, but each option occurs in a different, parallel, branching universe. Every time a choice is made, the universe branches. In this way, every possibility that could happen, does happen, just not necessarily in the universe we know as the one we live in. It also means that if I make it through this talk in this universe, in some other universe my computer self destructs, and in some other universe my car broke down on the way here. Everything that could happen, does happen, somewhere.

In this way, every possible value for every possible factor in our universe is played on in some parallel universe.

The question is, how do you test this Quantum-based multi-universe theory?

Unfortunately, the only way that has been defined really only tests the theory for the poor person running the test. Imagine the poor person who places a radioactive decay triggered gun at their head and steps into a box and waits to see if the world ends. With each moment the gun doesn’t fire, the world splits into a world in which the scientist dies, and a world in which she lives. If she continues to live beyond what statistics say is reasonable, than probability weakly claims that there should be other universe’s where the scientist has died. It’s a weak argument. It’s an a moral experiment, but… It’s at least one test we have the technology to do, even if no one will, I hope, ever do it.

Other methods are also being proposed, but we’re not in a position to run those experiments – the technology isn’t there. Perhaps in time, but not today.

So, while this theory is built on experimental results, and conforms to past experiments, it doesn’t make any useful predictions. In many ways, this theory, like string theory, is a nice bit of pretty mathematical art that might be true, but we really have no way of proving.

But quantum mechanics isn’t the only way to get at multiverses. According to Andrei Linde (of Standford University) and many others, it is possible that the field that drove the early period of inflation didn’t act the same way in all places. What if in some some places expansion continued, with fluctuations in the inflation leading to bubble universes expanding one from another extending on forever?

This “what if “ is layered on top of detailed theories that match our observed universe, and elegantly explain how inflation could have occurred. The multiverse falls naturally out of theories that drive the period of inflation with a (scalar) field that reacts to it’s environment. The early universe was filled with bubbling quantum fluctuations that acted like waves. As the universe expanded, the waves froze. The largest fluctuations froze first, and as the universe expanded, stretching the small waves with it’s growth, they eventually reached sizes where they also froze. Now, when waves interact, they can enhance one another or cancel one another. Depending on where you are sitting in this room, you hear my voice as louder or softer, depending on how the sound waves interact. In places, the interacting waves enhance my voice, and in the early universe, the waves in some places interacted to enhance the expansion.

In these spikes of chaotic inflation, new bubble universes could form, each growing out of a bit of the universe before it, each branching growing bubbling with it’s own physical characteristics. These universes can sprout out of one another nearly forever, and some theories suggest there could be 10^10^12 universes sitting along side one another, and in some cases branching off of our own universe. That’s a 1 followed by a trillion zeros of branching universes.

But, while this theory conforms to observations and explains what we experience, we currently have no way of knowing if it is true. Again, we have left the realm of testable science.

It seems, that with today’s technology and physics knowledge we must at a certain level label the first moments of the universe with the warning “Here be dragons.” We don’t know what set our universe in place, we don’t know why we are in a universe so precisely tuned to allowing life to exist. We have ideas, but… But ideas aren’t answers.

So this leaves us in a queasy place. In talking about the subject of this talk with my peers at SIUE, several put forward emotional opinions on what they want to be the truth. We all have our emotional feelings. But as a scientist, I look at untestable theories and have to say they really can’t be proven to be any more valid than Stephen King’s parallel universe series, the Dark Tower, in which there is one true universe and infinite child universes, with alternate, not real pasts and futures.

In this book, one of the characters, at the moment of his death, says “Go, then. There are other worlds than these…” In these words he propels the main character, the gun slinger to other truths, other possibilities, and other places in time and space. I don’t know if there are other multi-verses, parallel to this one, but I know our reality is not uniquely dictated by physics as we know it today. Our life in our universe is frighteningly improbable, and yet none the less real. Science doesn’t offer all the answers, but it does offer questions and a set of rules by which we can seek the answers.

For now, we are faced with three possibilities: Perhaps there is underlying physics that dictates our universe be one that allows us to be here. If that physics exists, I hope someone finds it quickly. Perhaps we live in some sort of a multiverse. If that is the case, I hope some experiments to test that possibility are defined soon. And, if it was a higher power that tweaked the parameters, I really hope he created some underlying physics that we can study and use to end at least this one line of questions while we open up many more. Science doesn’t answer the more fundamental questions of why does our universe exist and why is our universe the way that it is. All we can say is at the moment of the Big Bang, there be dragons.

<small>Images for this education presentation are from Getty’s Royalty Free Image collection (all photos), NASA, WMAP, jivaro, Corey Ford, and my own artwork. </small>

Needless to say, not everyone embraced the change.

These results rested solely on our understanding of type 1a supernova, which is an uncomfortable place to be (but that understanding seems to be solid, despite a mis-leading press-release earlier today.

There has always been the active question: Are the results real or is there something going on with the supernovae that we don’t understand that is making it look like the acceleration is there. Astronomers have taken two tactics in dealing with this problem: 1) Look for other lines of evidence that confirm the supernovae result, and 2) try and figure out supernovae better.

The new evidence hasn’t been easy to find, but since the supernovae results were announced in the late 1990s, other evidence has been found in the cosmic microwave background, in the large scale structure of the universe, and also in gravitational lenses. So… Even if we don’t fully understand supernovae, everyone (well, almost everyone at least) grudgingly acknowledges the universe is accelerating apart.

But the degree to which it is accelerating apart at what period of time (so far) can only be easily measured with supernovae. This means we really need to understand supernovae.

Now, at the most simplistic level (where accuracy is given up for clarity), Type 1a Supernovae are formed when a white dwarf star gravitationally consumes too much mass from a companion star and gravitationally collapses and explodes in one violent step. Since all white dwarfs become explosive (to first order) at the same mass, they all have the same amount of material to contribute to the explosion and they all create an explosion of the same size. Thanks to the luminosity-distance relationship, we can measure how bright a supernova appears with a telescope and compare that to how luminous it actually is to calculate how far away it is (This is the same thing you do when you estimate the distance to a motorcycle on how bright its headlight appears). Once you know how far away a supernova is, you can measure its recession rate with a spectroscope. (These are actually very hard to do technically, but that’s what graduate students are for).

At the next level of complexity, we know that Type 1a actually show some variation. Some take a longer period of time to fade away and give off more energy. Others fade faster and are fainter. Now, since we know how the supernovae’s total light output changes as a function of their lightcurves’ shapes (with error bars), we can correct for this second order effect. No big deal. This is like knowing that when you put giant wheels on your car you have to fix your odometer to compensate for the car go farther for every one turn of the tires. Like I said, no big deal, this is something astronomers just have to be more aware of. We even think we understand why this is happening (see link). Okay, nothing to worry about, move along.

But there is still another problem. It a fact that there are more metals in the universe today (defined by astronomers as anything heavier than Helium). There are Sun’s creating carbon, and iron and everything in between all across the cosmos, and every exploding star releases a variety of everything and anything nuclear reactions can create. This means the stars that are forming today are forming out of materials that where just a twinkle in a young giant star’s eye some day in the past. The first stars were almost pure hydrogen and helium. Those stars have very different physics from today’s stars. Metals moderate the formation of stars, making stars form smaller and burn in a more controlled way. When white dwarf stars first started forming, they had fewer metals than modern white dwarfs and that could have effected how supernovae explode, causing supernovae to vary as a function of time in ways that we don’t know about.

Earlier today a press released crossed-my inbox that said, “distant supernovae were an average of 12 per cent brighter. The distant supernovae were brighter because they were younger.” On first read, it would seem to imply that supernovae have gotten brighter as a function of going back in time. This would imply that supernovae luminocities are a function of lightcurve shape and when the supernovae exploded. Eek! Things got much more complicated! But, the press release goes on to say, (words of my former classmate at U-Texas and now U-Toronto Post Doctoral Fellow, Andy Howell) “We found that the early-universe type 1a supernovae had a higher wattage, but as long as we can figure out the wattage, we should be able to correct for that. Learning more about Dark Energy is going to take very precise corrections though, and we aren’t sure how well we can do that yet.” This seems to imply that yes, things are getting complex but we can indeed cope, but there will be error bars.

Not liking this new reality, I went and found the actual paper (subscription required to get beyond the abstract, but please read the abstract). Ummm, if I’m reading this right, the average luminosity of supernovae is changing, because the ratio of brighter ones to fainter ones is changing, but the type 1a supernovae themselves are still totally predictable within error bars. The faint ones act the same (but there are fewer), the bright ones act the same (but there are more of them), and the average changes while the physics (within error bars) is respectably well (within error bars) understood.

No, type 1a supernovae aren’t totally standard candles. They don’t all give off the exact same amount of light and they don’t all explode in the same way. They are a family of candles and we know how bright they all are, each in their own unique way (with error bars).

The way they found this possible void is really neat science. First they noted that there was a really cold spot in the CMB. This can mean two different things. It could simply mean the particular part of the universe that emitted those cosmic ray photons was actually anomalous, or, it could mean there is less stuff in that direction that is tweaking the light from the CMB. As the light comes through the universe, various interactions can increase the energy and wash out the details in the CMB. Without those secondary effects, we see a cold spot.

To distinguish between the two cases, astronomers lead by Lawrence Rudnick Shea Brown and associate professor Liliya Williams (University of Minnesota) looked at the New VLA Sky Survey (NVSS) to see if the distribution of radio bright galaxies in that direction also indicated there was a void.

And guess what – It did. There is simply nothing in NVSS in that direction.  By it self, the lack of radio sources in that region of the sky simply indicates there isn’t a lot of action going on in that part of space. Extragalactic radio sources fall into two broad categories: star forming galaxies (but these are generally fairly radio faint), and active galaxies (including Quasars). These active galaxies may have radio jets or appear as small centroids of radio brightness in radio maps of the sky. All these systems have actively feeding supermassive black holes in their centers. A void in radio galaxies alone only tells us there are no feeding supermassive black holes and no nearby star forming galaxies in that direction. While radio galaxies generally loosely trace the population of all galaxies, there are groups of galaxies out there without associated radio galaxies – this could have just been a huge batch boring space, or there could have been no galaxies to be traced by radio galaxies.

By itself, either of these things don’t indicate anything really meaningfully exciting and at all conclusive. Put together, this points at a whole lot of nothing.

It’s still not totally conclusive. I’d like to see some deep imaging that looks at gravitational lensing as a function of redshift to see if the void can be three dimensionally traced out. This would also nominally show of visible galaxies, creating a very empty deep field image. There is a lot of neat research that may be doable in this new void. Currently, even the most empty voids have a galaxy here or there inside of them. This void could have a whole bunch of very isolated stuff inside of it that we can study. Potentially, it will allow us to study the evolution of isolated objects over a billion years. While that is only ~1/14th of the age of the universe, that is still a fairly good chunk of time and space to explore.

We know from our studies of Abell clusters what space looks like in the direction of the most dense objects, we know from the deep field images what space looks like in the direction of the most average chunks of space, and now we have the opportunity to explore the most diffuse areas of space.

Okay, so that last one is an exaggeration. As far as I know, human babies and the CMB have nothing in common. The remark about the Oort Cloud, however, may not always be as far fetched as it sounds. A group of scientists working at the Harvard-Smithsonian Center for Astrophysics, and lead by David Babich, have theorized a new technique for determining the mass distribution in the Oort cloud using distortions in the Cosmic Microwave Background.

According to the theories of Babich and his team, if you observe the light of the CMB through the Oort cloud, the intensity you detect is related to both how much CMB light is blocked by Oort cloud objects (which are so small and so far away that you can look through them the way you look though a cloud of fine dust), and to how much light the Oort cloud objects emit at the color being observed (in this case, the dust you are looking though is made of glow in the dark paint). If the Oort cloud isn’t symmetrical, any distortions may be visible as anisotropies in the light of the CMB.

The key to understanding this result is understanding that warm objects give off light in a variety of colors. The hotter an object is, the shorter the wavelength of the light – the bluer the light. The colder an object, the longer or redder the light will be. Humans, for instance, give off the most light in infrared. That doesn’t mean we give off all our light in any one specific wavelength of infrared. Rather, we give off most of our light in one shade of color, but there is light of a variety of colors coming from our warm bodies, even in the darkest of rooms (although some colors, like green, aren’t emitted in numbers enough higher than zero to matter).

The CMB is basically a perfect black body with a temperature of 2.728 Kelvin. It is located at essentially infinity in all direction. It is a perfect background light. This team theorizes that objects in the Oort Cloud should have temperatures related to their distances, such that an object at 1000 AU would have a temperature of 8.5 K and nearer objects would be hotter while farther objects are colder (think of the temperatures of rocks illuminated by a camp fire. The same physics describes the heat of the rocks and of the objects in the Oort Cloud. These temperatures are very similar, and the same technology that can be used to detect the CMB will also detect the heat signature of Oort cloud objects.

So, while the 2.728 K CMB and 8.5 K Oort cloud objects both emit microwave light, the light doesn’t peak at the exact same color, although there is overlap. Despite the amazing precision that WMAP and other missions have already mapped the CMB, their accuracies weren’t sufficient to test this theory, but this is something that future missions, like Planck, may be able to. Any distortions in the Oort cloud that are found will point to past encounters with stars. As our Solar System passes near other stars on its orbit through the galaxy, the Oort cloud gets distorted and these distortions trigger long period comets.

Good theories, in my mind, are defined as theories come in to forms. There are those, relativity, that put existing observations together in a new way that leads to deeper understanding and understanding of previous mysteries, while also making predictions. There are also good theories that look at the universe and apply existing knowledge to predict future discoveries we can’t get to through more common means. This set of papers falls in that second category. This isn’t theory for the sake of pretty math – this is theory that defines how to build a better mouse trap.