>> Kirsten Wiley: Good afternoon and welcome. My name is Kristen Wylie and I'm here to
introduce and welcome Richard Panek who is visiting us as part of the Microsoft research visiting
speaker series. Richard is here today to discuss his book, The 4% Universe: Dark Matter, Dark
Energy, and the Race to Discover the Rest of Reality. It's hard to imagine that what we can see,
touch, hear, smell and taste is just 4% of what is actually out there. The rest of the universe is
unknown. It is dark, and scientists have been working hard to determine the roles dark matter
and energy play. The 4% Universe traces the path of one of the most mysterious scientific
concepts we know of today. Richard Panek is the recipient of a Guggenheim Fellowship and the
author of the Invisible Century and Seeing and Believing. He has frequently written for the New
York Times, as well as Discover, Smithsonian, Esquire and Outside. He has received a New
York Foundation for the Arts Fellowship in non-fiction literature and has an Antarctic Artist and
Writers Program grant from the National Science Foundation. Please join me in welcoming
Richard Panek to Microsoft. Thank you.
>>: [applause].
>> Richard Panek: Thank you. Thanks for coming out. This is a great turnout. I appreciate it.
Thank you to Microsoft for inviting me. And thank you, Kristen, for that introduction.
Over the weekend I was signing books at the air and, one of the air and space museums in
Washington, and there was a table and I was sitting there signing books. And there was a
cashier there and the cashier, you know, was just flipping through the book, and she read the
inside flap, and she went, “Wow! That's crazy.”
And I, I, I thought, that's the perfect response.
>>: [laughter].
>> Richard Panek: It’s like it was great; it was very gratifying, because it is crazy. And about, I
know that sounds like a made-up anecdote, but it's actually true. And as soon as it happened I
thought, oh, I can use that in talks.
>>: [laughter].
>> Richard Panek: So what I'd like to do is put this -- I mean this is truly a revolutionary concept
in science. And you hear those words a lot and I was very glad to see that one of the early
reviews said, this is a media cliché, but in this case it's not. I mean, this is from scientists’ points
of view. From the scientific community, this is really revolutionary and it's something that, that the
public and probably, well, who here has heard of dark matter dark energy, those ideas? Yeah, so
most people have. But the whole, the enormity of the concept and what it's going to mean hasn't
really penetrated and that was actually part of why I wanted to write this book.
I thought about it a lot; I researched it a lot. And like that cashier I was talking about, my first
response was something like, wow, that's crazy, or that's wild, or that's too wild to be true. This is
about 10 years ago when I first started hearing about it when I would go to conferences as part of
my research. But then the more I looked at it, the more I realized that I wasn't hyperbole. It
wasn't just some PR thing, but that it was actually, the scientists themselves were taking it
seriously, the astronomers and the theorists, the cosmologists the astrophysics, physicists. And
as I saw them taking it seriously and trying to knock down these ideas and failing and convincing
themselves, I became more convinced until I thought well this is a story worth telling. How they
reached that point so this is a very human story in terms of people really working through these
problems. So what I'd like to do, I know that these things aren't usually readings, and I'm not
going to read much, but I think to set up what I'm going to talk about, I would like to read the
prologue which is only three pages long and it'll take about 5 min. So if that's all right, I'll do that
and then I'll kind of walk through the rest of the story.
So this is a prologue so you don't need any setup, except that it's brilliant, but other than that.
>>: [laughter].
>> Richard Panek: The time had come to look inside the box. On November 5, 2009 scientists
at 16 institutions around the world took their seats before their computer screens and waited for
the show to begin. Two software programs being run by two graduate students: One at the
University of Minnesota, the other at the California Institute of technology, simultaneously. For
fifteen minutes, the two scripts would sort through data that had been collecting far underground
in a long abandoned iron mine in northern Minnesota. Over the past year, 30 ultra-sensitive
detectors, deep freeze cavities the size of refrigerators, shielded from stray cosmic rays by half a
mile of bedrock, their interiors cooled to almost absolute zero, each interior harboring a heart of
germanium atoms, had been looking for a particular piece of the universe. The data from that
search had sped from the detectors to off-site computers, where following the protocol of a blind
analysis, it remained in a box out of sight.
Just after 9:00 AM central time, the un-blinding party began. Jodi Cooley watched on the screen
in her office at Southern Methodist University. As the coordinator of data analysis for the
experiment, she had made sure that researchers wrote the two scripts separately using two
independent approaches so as to further insure against biased. She had also arranged for all the
collaborators on the project, physicists at Stanford, Berkeley, Brown and Florida, Texas, Ohio
Switzerland to be sitting at their computers at the same time. Together they would watch the
evidence as it popped up on their screens one plot per detector, two versions of each plot.
After a few moments, plots began appearing, nothing, nothing, nothing. Then three or four
minutes into the run, a detection appeared, on the same plots in both programs. A dot on a
graph, a dot within a narrow desirable band, a band where all the other dots weren't falling. A few
minutes later another pair of dots on another pair of plots appeared within the same narrow band.
And a few minutes the programs had run their course. That was it then, two detections. Wow!
We thought. Wow! As in, they'd actually seen something, when they had expected to get the
same result as the previous peek inside a box of different data nearly 2 years earlier, nothing.
Wow! As in, if you're going to get detections, two is a frustrating number, statistically tantalizing,
but not sufficient to claim a discovery. But mostly, wow, as in, they might've gotten the first
glimpse of dark matter, a piece of our universe that until recently, we hadn't even known to look
for, because until recently we hadn't realized that our universe was almost entirely missing.
It wouldn't be the first time that the vast majority of the universe turned out to be hidden to us. In
1610, Galileo announced to the world that by observing the heavens through a new instrument,
what we would call a telescope, he had discovered that the universe consists of more than meets
the eye. The 500 copies of the pamphlet announcing his results sold out immediately. When a
package containing a copy arrived in Florence, a crowd quickly gathered around the recipient and
demanded to hear every word. For as long as members of our species have been lying on our
backs looking up at the night sky, we had assumed that what we saw was all there was. But then
Galileo found mountains on the moon, satellites of Jupiter, hundreds of stars. Suddenly we had a
new universe to explore. One to which astronomers would add over the next four centuries new
moons around other planets, new planets around our sun, hundreds of planets around other
stars, 100 billion stars in our galaxy, hundreds of billions of galaxies beyond our own.
By the first decade of the 21st century, however, astronomers had concluded that even this
extravagant census of the universe might be as out of date as the five planet cosmos that Galileo
inherited from the ancients. This new universe consists of only a miniscule fraction of what we
had always assumed it did. The material that makes up you and me and my laptop and all those
moons and planets and stars and galaxies, the rest, the overwhelming majority of the universe is
who knows? Dark, cosmologists call it in what could go down in history as the ultimate semantic
surrender. This is not dark as in distant or invisible. This is not dark as in black holes or deep
space. This is dark as in unknown for now and possibly forever. Twenty-three percent
something mysterious that they call dark matter. Seventy-three percent something even more
mysterious that they call dark energy, which leaves only four percent, the stuff of us.
As one theorist likes to say at public lectures, “We’re just a bit of pollution. Get rid of us and
everything else we've ever thought of as the universe, and very little would change. We're
completely irrelevant,” he adds cheerfully.
All well and good, astronomy is full of homo sapiens’ humbling insights. But these lessons in
insignificance had always been at least somewhat ameliorated by a deeper understanding of the
universe. The more we could observe, the more we would know. But what about the less we
could observe? What happens to our understanding of the universe then? What currently
unimaginable repercussions would this limitation and our ability to overcome it or not have for our
laws of physics and our philosophy, our twin frames of reference for our relationship to the
universe? Astronomers are finding out. The “Ultimate Copernican Revolution” as they often call
it is taking place right now. It's happening in underground mines where ultrasensitive detectors
wait for the ping of a hypothetical particle that might already have arrived or might never come,
and it's happening in ivory towers where coffee break conversations conjure multi-verses out of
espresso steam. It's happening at the South Pole where telescopes monitor the relic radiation
from the Big Bang. In Stockholm were Nobellas have already begun to receive recognition for
their encounters with the dark side, on the laptops of post docs around the world as they observe
the real-time self annihilations of stars billions of light years distant from the comfort of a living
room couch.
It's happening in healthy collaborations, and the universe being the intrinsically Darwinian place it
is, in career threatening competitions. The astronomers who have found themselves leading this
revolution didn't set out to do so. Like Galileo they had no reason to expect that they would
discover new phenomenon. They weren't looking for dark matter. They weren't looking for dark
energy. And when they found the evidence for dark matter and dark energy they didn't believe it.
But as more and better evidence accumulated, they and their peers reached a consensus that the
universe we thought we knew for as long as civilization had been looking at the night sky, is only
a shadow of what's out there. That we have been blind to the actual universe because it consists
of less than meets the eye. And that that universe is our universe. One we are only beginning to
explore. It's 1610 all over again.
So that's the prologue and I wanted to read it so that you would get a sense of the historical
perspective, the historical setting for this for this discovery. That my argument in the book and it's
one that scientists would agree with, is that this is a revolution in thought and in science on a
scale with the one that Galileo had in validating the Copernican interpretation of the universe.
The Copernican interpretation of the universe, of course, has the sun at the center and there's
been a kind of misunderstanding over the centuries. The mythologizing that this was a blow to
our ego, in fact, it wasn't. The center of the universe was seen as the bottom of the basement.
You know, the bottom of the house, the basement, where everything impure fell. So on the
celestial of things outside of earth were beautiful and perfect. So it wasn't really a demotion to
have the sun at the center; it was just counterintuitive and it presented problems to the church, of
course, and there's all sorts of, you know, we know that history.
But the lesson that we took from it in saying that we are not the center, so it's not a blow to the
ego, but it's just, it's a rethinking of the universe, that there is no privileged place in the universe.
And by privileged, and I don't mean speciaI; I just mean that there is a place that is actually the
center. Same thing now with this, that were finding out that 4%, that the universe that we've
always thought of is only 4% of what's actually out there in terms of the matter and the energy
and Einstein tells us that matter and energy are interchangeable. So that's really it for the
universe. So there's 4% that we know of. And this other part is mysterious. So finding out that
we are only, that what we've always thought of, what astronomers have always looked at, as only
4% is perhaps humbling to our egos in terms of, of our investigatory or investigative prowess but
it's not a blow in any other sense except that it's consistent. It's consistent that we are not
special, that there is not this special frame of reference.
Okay so let me back up now excuse me.
>>: [takes a drink of water]
>> Richard Panek: So let me backup now and say where these ideas come from. In the 1970s,
starting in the late 1960s, and then throughout the 1970s astronomers were observing the
motions of galaxies. They were observing the individual motions of galaxies. You know the
spirals that circle, and they were observing the motions of how galaxies interact with other
galaxies and clusters and they were looking at computer models of our own galaxy, and what
they were finding consistently is that galaxies moving at the rate that they're moving, orbiting or
rotating at the rate of their rotating should be shredding apart according to the laws of Newton.
They should be sending gas and stars in every direction. The Milky Way galaxy, our galaxy
which has gone through, I think it's a dozen rotations so far, shouldn't have survived the first
rotation based on the matter that we can see. However, if you say that there's other matter there,
and the computer simulations that they ran, these were primitive, primitive things that were done
with punch cards and FORTRAN and stacked in feeders that went into huge things like this. That
those computer simulations showed that if you take the galaxy, the spiral galaxy, and you, and
you put like a halo of dark matter on it, it still didn't stabilize--I mean dark matter, whatever it is-that they, they didn't use the term dark matter yet, but this mystery matter, it didn't stabilize the
galaxy. So they made a bigger halo, and that didn't stabilize, and they kept making bigger halos
until finally the halos were like this, and the galaxy was like this. And then it stabilized.
And that was tough to believe, and people fought against it as you might expect. The observers,
there was this one observer in particular who I spend a good deal of time in the book, she's just
great. Vera Rubin just went out and made these observations again and again, galaxy after
galaxy. You could see it; you could plot it. The rotation was called the rotation curve of the
speed against the velocity of the rotation. And you would just see the line stay flat, the velocity
versus distance. You would just see the line stay flat. It should fall off at distance in the same
way that in the solar system Pluto moves at a rate that is much slower than Mercury, which is
doing this, right? So but this is as if Pluto were keeping pace with Mercury. That didn't make
sense. So they have this dark matter. Now that raises the question of how much matter is there
in the universe, if there's all this other dark matter? And there was also another line of
investigation that was turning up at this point on the particle physics level which I don't need to go
into; it's in the book, but it was also saying oh, there would need to be other matter there as well.
But in terms of the community, it was really these beautiful observations of galaxies that
convinced a lot of people. So if you have all this matter and you estimate that 80% of the matter
is dark in the universe, you start to say, okay, well how much matter is there in the universe, and
what will the effect be on this kind of eternal question of the fate of the universe? Once you know
how much matter is in the universe, and you know how much, at what rate the universe is
expanding, you can put those two pieces of information together and find out what the fate of the
universe will be. Is there enough matter that the expansion, and this goes back to the Big Bang
interpretation of Hubble's observations of galaxies in the 1920s, is the universe expanding like
this and slowing down so much there’s so much matter interacting gravitationally that it does this?
Or is it doing this and just kind of petering out?
So two teams of astronomers using the same kind of methodology looking at supernovae, these
exploding stars from far away in the universe were, were, started investigating this and observing.
And actually I'm going to take advantage of this and I don't usually use visual methods but it
occurs to me that in this, in this environment it might make more sense. If you have what's called
a Hubble diagram, if you have velocity versus distance of, I'm sorry distance versus luminosity,
you have galaxies that pretty much lie along a straight line. The more distant they are, the less
luminous they are and you can graph it. And Hubble did this in the 1920s, and then other
astronomers did this over time, but at some point this line is going to have to change, because
this line holds only if there's no matter in the universe. That something distant will, will the
luminosity will fall off at a greater distance and continue along this, this relationship, this straightline relationship only if there's no matter in the universe, right? But if there's matter, then gravity
is going to have to slow this, at some, is going to have to slow the expansion at some point and
the luminosity will fall off, because the objects will be, will appear to be closer, right? As it slows
down, right? Rather than a uniform expansion where they would go like this, at some point they
start to slow down, and it would be like this. So they would actually be a little bit, they’ll be a little
bit brighter right? They’ll fall off like this, okay? So these two teams in the 19--does this make
sense? Are you following me? Okay. Good. So these two teams in the 1990s, were trying to
figure out, they were using supernovae, using them as standard candles, so called standard
candles, to see at what point would this, would they reach this point where they would start to get
where the supernovae would start to get brighter. And how this curve would determine how much
matter there was in the universe.
So they were doing this throughout the 1990s, and they didn't like each other, these two teams.
And this goes, and I go into some detail on this in the book. It's actually, they were highly
competitive. One was primarily a group of physicists from Berkeley, and the other were
astronomers primarily based at Harvard, but also in Chile and Australia and they, the
astronomers didn’t like the physicists were getting in on their territory. And the physicists didn't
like that the astronomers were coming along after the physicists have been working on the
program for six years or so and suddenly, well from their point of view, suddenly saying hey,
we’re going to try this too and we’re astronomers and we can do it better than you. So there was
all this animosity between the two.
And this peaked in the 1996, 1997, and there's actually one instance that's in the book, and I
don't think it's been reported elsewhere, but at one point the Berkeley team went to the director of
the space telescope Institute which is the Hubble programming headquarters in Baltimore, in the
Johns Hopkins campus, and said to him, you know, he went up to him in an astronomy meeting
and said you know we have this method that we’re using to find these distant supernovae and if
you use the Hubble space telescope we can really refine the measurements. And the Hubble
space telescope was supposed to be used only for the things that you couldn't do from the
ground, and you could do supernovae searches from the ground. But the director said that's a
great idea; that's great science. So he knew members of the other team. So he went to them,
the rival team and he said, Saul Perlmutter, of the Berkeley, said Saul has this idea for this
program. What do you guys think? And Bob Kershner at Harvard said that's a terrible idea. You
should only be using Hubble to do observations for things that you can't do from the ground. And
the director said, yeah, but you know, this is really interesting and it's really good science. And
Kershner and his two other astronomers on his team were going no, no, no; we don't want this,
this is the wrong approach. You shouldn’t let Saul do this. And after a while, as one of the
astronomers in the room described to me, it kind of dawned on everybody that what the director
was saying was, ask for time, I will give it to you.
So when the other team, when the physicists found out the astronomers were giving each other
breaks, they got, they got really upset. In any event, the observations that the two teams made
using the Hubble space telescope proved to be decisive. And what those observations found
was that the universe wasn't doing this. It was doing this. Which means that, it was that the
supernovae were less luminous at a certain distance. That they were in fact farther than they
should be. And that implies an accelerating universe rather than a universe that has all this
matter in it and all this gravity that’s slowing it down, something was speeding the universe up.
Now this is, again, a counterintuitive discovery just like dark matter was, that there's more to
galaxies than we can see, in any regime of the electromagnetic spectrum. So this is a difficult
concept; they tried to knock it down. They couldn't knock it down, and eventually they said we
have results; let's publish. So they published.
And the community found it compelling that these two extraordinarily competitive teams who
wanted nothing better than to prove the other guys wrong were both reaching the same
counterintuitive conclusions. That was immediately taken seriously, like within months people
were taking it very seriously. They didn't quite, you know, condone it or believe it yet, but they
really, but they really felt like maybe there's something here. So this was in 1998, 1999. People
are starting to take it seriously. There's, in 2001 one of the astronomers Adam Reese on the
astronomy team realized that, that you could kind of seal the case. I mean, you know, you can
say, okay, it looks like it's speeding up but what if we don't really know much about supernovae?
What if there's gray dust between here and the supernovae? What if there's the, you know,
there's all sorts of other factors. What if we can't really take these results seriously? As so they
thought, well, if it's some, if the universe is accelerating now at some more distant era out here
and by distant, we’re talking about far back in time right, because light takes a finite amount of
time to reach us.
So now the universe is speeding up but at some earlier time when the universe was smaller,
matter would have been the primary, would have been primarily under the influence of gravity and
the universe would've been slowing down. So he said how, astronomers said how can we find
the point where it might be slowing down? That is the supernova would begin to become dimmer
than we would expect, I'm sorry brighter than we would expect in this area here. And he, and he
realized that there might be in the archives of the Hubble space telescope a supernovae from far
enough back in the universe that they could make the measurements on it. And there would be
follow-up observations by Hubble. Very unlikely, but he knew that there had been two
supernovae observed in late 1997, and he went into the archives and he thought, you know, this
isn't going to happen but, let's see what happens if I run, if I say, did these two supernovae in this
one particular part of the sky very, very, very small part of the sky, did they somehow get
captured by Hubble which is looking in every direction? Somehow in the following months or
years or months, actually, before they faded from view?
So he ran the program and sure enough it was there because there happened to be a new
instrument on board and they were using it, and they were testing it just happened to be testing it
the at exactly that part of the sky. So, I mean it wasn't exactly, it's like sometimes one of the
supernovae was off or it was out of the frame, or the other one, but there were enough
observations that he can actually extract the data from it and I was at this conference in 2001,
where he presented the data. And the other astronomers in the room, there were about 100 of
them already knew it was going to happen because it had been announced at their press
conference in Washington the day before. But a lot of things get announced at press
conferences and they don't take it seriously until they see the data for themselves.
So he walked them through it and he came up with one of these diagrams again, and this was, he
was still using an overhead projector. And so was, and he was sitting here with this projector and
he's moving something covering a sheet of paper, something covering it, and so he's moving it so
we only see, you know, he’s got part covered so we see this part that we already know here. And
he shows us some more supernovae that are on the straight line, and then he shows here where
it's doing, where it starts to leave the straight line. And then this new supernova was about twice
the distance as the others, and he's doing this, it’s kind of like a striptease. And so he goes,
moves this one aside and it’s like down here.
You know, and the people in the room just gasped, and it convinced a lot of people that they had
to take this seriously. Now where do we come up with the numbers 73% dark energy, 23% dark
matter, 4% the stuff of us? For that astronomers over the past 10 years have been looking
closely at the cosmic microwave background. And you probably have heard of that and you
might know what it is, but just as a reminder, a few hundred thousand years after the Big Bang, or
what's called the Big Bang, matter and energy went their separate ways. And this is imprinted in
the microwave background all around us. And in fact in the old days if you were flipping channels
on a TV and there was like all that static on channel 3 or channel 6 or whatever, that was I don’t
know about 5% or something like that was these microwaves from the Big Bang, okay?
So people were looking at the Big Bang before they knew what they were looking at. So this
cosmic microwave background is imprinted on the sky in microwaves. And it's almost entirely
uniform. It was discovered in 1965; it was observed actually in 1964, but the interpretation came
out in 1965, that there was this kind of uniform background. But it can't be entirely uniform, or
there wouldn't be anything in the universe and obviously we’re here. So there’d have to be some
degrations in there.
In the early 1990s a satellite called the Cosmic Background Explorer, or COBE, observed some
of these degrations in just the right amount that it would make sense that it would match the
predictions of the Big Bang. So a lot of people, so that really turned the corner for the
interpretation of the Big Bang universe. And people really started to, they’d already taken it
seriously, but they really started to say, okay, this is valid because we have this, we have this
prediction and we have this observation, and the observation matches the prediction and that’s
the scientific method. So suddenly cosmology, which used to be metaphysics, is now entering
the realm of science. So, and that experiment, the COBE experiment, won the Nobel Prize in
2006.
There was a follow-up called the Wilkinson Microwave Anisotropy Probe, or WMAP, which sent
back its first data I think in 2003, and then every year or so they would refine the measurements,
the observations a little bit more. So what they do is they run, is they take this really exquisitely
precise map of the sky and you've probably seen it. It has like blue and yellow in it and it's like an
oval shaped and it's an all sky map? And these differences are differences in temperature that
tell them where the matter and the energy went it separate ways. You can run a similar, you can
run computer simulations; you can simulate a million universes or 10 million universes and you
can say, I'm going to stimulate the universe that has 100% matter and no energy in it at all. And
that would look one way. And you can say, oh, I'll have a universe that has 63% matter and 47%
or rather 37% matter and that would look different. So they run these millions of simulations; they
match it up with the data, the readout from the WMAP, and they begin as they get the data, and it
becomes more and more refined over the past decade it becomes more and more precise and
they are able to say, oh, it matches this universe. It matches this even more precise universe and
then the universe that it matches this one that has 73% dark energy, 23% dark matter and 4% the
usual stuff that we think of as the universe. So this is a very compelling, very compelling
argument, and people take it really seriously, and that's where I said at the beginning that people
say that this is a genuine revolution.
The question still remains, what are these things? We take them seriously. What is dark matter?
There were in the 1970s, a standard model was, was being filled out but there were still problems
with the standard model. I should, I should add here that I'm not a scientist; I'm a writer. So there
are points where I reach the limits of my understanding, and I'll let you know when they happen.
And during the Q&A I reserve the right to say, I don’t know.
>>: [laughter].
>> Richard Panek: But what I do as a writer is I research the stuff extensively and I learn it, and
because I'm coming from a background of complete ignorance, zero knowledge, I figure out, I try
to figure out like how can I use my process as a way to formulate a narrative for the reader to
understand this, this knowledge in some way that it becomes accessible to people who are nonspecialist, people who are even afraid of science, I hope. So when I start getting into the
standard model, I can't really go very, very deeply and I had to learn some of it for the book and I
got something entirely wrong. And a physicist was reading an advance copy and he got in touch
with me and he said you, you, that paragraph is totally gibberish. And I looked at it and I said
yeah, you're right. So, but I managed to fix it in time for the book.
So the standard model had some, had imperfections in it, and there were two particles that could
solve some of the problems. Hypothetical particles, right? We don't know if they exist. One is
called an axion and one is called a neutralino. They have properties. If they exist, they would
exist in the quantity and at the mass level that if you multiply the quantity times the mass, it would
actually make up this 23% dark matter component. Now at the time they didn't know about dark
energy so they were just saying how much of the matter in the universe, and they would say it
was 80%, of the, that the dark matter was 80% of the matter in the universe. So these two
particles seem to be very strong candidates. So they begin to set up experiments to find, if they
could, to somehow catch these particles. And because these particles, if they exist, would exist
by the trillions, and they would be passing by the trillions, I mean, by the trillions per cubic
centimeter, would be passing through you now as we sit here. They would be plentiful, but we
haven't yet figured out a way to capture them in the 1970s. So they worked on this one that I
read to you from the prologue. That was the experiment in the underground mine, was looking
for neutralinos. And they would interact with something and then it would create this detection.
And the axion is, it's kind of gorgeous, and I'm kind of rooting for it because it's the underdog. But
they would take a cavity and with an extraordinarily strong magnet they would, you know, get rid
of all the light in a cavity. And the axion, if it exists, would interact with magnetism and turn into a
photon, which we would be able to see and detect. And with that photon would probably trigger a
chain reaction and create other photons. But they don't know what the frequency would be, so
they have this beautiful experiment, it was, I visited it at Lawrence Livermore. This cylinder, this
cavity that is that they're looking for this particular signal, but they don't know what the frequency
would be, and it's so, it's so faint that it's like ten to the 20 times faint, no, that's not right. No, it's,
I'm sorry, it's like two or three orders of magnitude fainter than the last signal from the Pioneer
that left the solar system. So and at least in that case NASA knew where the signal was, what
the frequency was, and in this case they don't know what the frequency is.
And so they're looking for this extraordinarily faint signal, and they don't really know where it is.
So they just have to methodically go through the radio dial, so to speak, looking for the signal.
And it's this kind of, I don't know, quixotic adventure. But, but if the axion exists, this experiment
will find it. It’s just going to exhaust the whole, the whole spectrum that it could be at.
So I think that's a lot of fun. So those are two candidates. But starting in the 1970s, when people
started looking for them, they said well now we know. We have an idea of what we're looking for
and we can build the instruments that will find them. So we’ll probably find out what dark matter
is the next five years. And people made this prediction, and five years would pass and then they
would say it again, and eventually they were saying well, in the next 10 years. And that passed,
and the most recent one I saw was, well, there were two. One was in 2001, and I mentioned
Vera Rubin, this discoverer of the flat rotation curve in the 1970s. I was at a conference and she
said, everybody keeps saying it's going to be found in the next 10 years. I said that in 1980. I
think we have to stop saying this. And then I saw her over the weekend in Washington and she
said, you know, in 2005 there was another conference and people got upset with me, because
people were standing up and saying we’re going to find it in the next five years. And I said people
been saying this for the last 25 years; we have stop saying this. And they said, no, this time it's
true. Of course, now it's 2011, so it's been six years since that last prediction.
So that, this is really perturbing them. Okay, so that's on the dark matter side. On the dark
energy side, it's not so much a matter of what is it. They don't, at this point, it's just a matter of
figuring out how it behaves. So the experiments that they're designing now that they been
running for the past few years, are trying to figure out this dark energy this, this energy, this
whatever it is, this component of the universe that is overwhelming gravity on a cosmic scale and
causing the acceleration to speed up. Is this; is it constant over space and time, or does it
change over space and time? So they don't even know, I mean, it's not a matter of well, what is it
exactly? They're just trying to figure out like on this, on this cosmic scale, how does it, how does it
behave, before they can even begin to figure out the other issues. Complicating dark energy is
that according to quantum mechanics there can be, there's no such thing as empty space, right?
That anti-particles are, I'm sorry, virtual particles are popping into and out of existence. As one of
the discoverers of dark energy told me, he said, you know there's this circus, you know like we’re
sitting here reading the newspaper and there’s this circus that's going on around us and we just
can't see the world on the quantum level.
But according to quantum theory, if this kind of vacuum energy, if this energy exists, it should
exist at 10 to the 120 times more powerful than what it would be in our universe. I mean it at 10
to the 120 times, the universe wouldn’t exist. I mean, it would just be, fssss, you know, it would
have, would've obliterated in the first fraction of a second. So we know it's not 10 to the 120, but
we know it's not zero, because we would be making this observation. We know that it's like
really, really small. Why should it be so small? Why should there be this 10 to the 120, or if you
do other calculations 10 to the 60, or if you do other calculations 10 to infinity? Why should there
be that kind of discrepancy between observation and theory?
The problem is that we can't reconcile general theory of relativity with quantum theory. The
general theory of relativity, of course, describes the universe on this grand scale, where we can
see the interactions of these big things, these galaxies, or we can, or we can predict the motions
of planets. Quantum theory, of course, exists on the very small level and they can't get the two to
match. Which I'm sure you're aware. Einstein worked on the problem, other people worked on
the problem, but it's dark energy that is really brought that problem to the forefront in a way that
scientists have to say, okay, now we really have to take this seriously. We’ve been able to live
with this discrepancy for the last 70 years or so figuring that at some point somebody would come
along and figure it out. But now it's not only that sometime somebody will come along and figure
it out, but somebody has to come along and figure it out, because otherwise this part of the
universe, this 73% is totally unknown and seems to contradict all the laws of physics as we know
them. So this is part of why they're saying that this is a revolutionary moment. Because we’re
going to need to reconcile these two in order to figure out what the universe is. Will that happen?
Maybe not within our lifetimes, maybe never.
And this, again, is kind of the dark matter problem where they've been running these experiments
for 30 years now and haven't been able to find these two candidate particles. What if they don't
find the particles? What if they need detectors or if they need accelerators that are beyond the
scope that we can build or we can afford to build? So this is a problem in that community, in the
particle physics community, wondering whether or not even if the particles are out there, will we
ever be able to get to them.
Same thing with dark energy. How are we going to be able to, are we going to be able to
reconcile these two grand theories? Each one makes sense; it makes predictions. It's totally
consistent within itself. But they’re inconsistent with each other. So that's the point that
astronomy, cosmology and physics is at today. There don't, they don't know whether or not
they're going to be able to solve these problems. They know, they feel very strongly that these
two components of the universe, the dark matter and dark energy exist, but they don't know what
they are or how or whether or not they're even going to be able to find them. And this obviously
can have very profound implications for physics, as I said, and for philosophy, in some way. In
the same way I think that, as I started in the beginning, that Galileo's revolution had these
repercussions. You know, when Galileo was observing the moons of Jupiter, you would have
been hard-pressed to say, wow, in a hundred and fifty years we’re going to have the
enlightenment and then democracies, and there'll be revolutions based on the idea that the
individual’s in control of information, not the church. Not the King. But that the individual can
make these observations and then somebody else with the same instrument, and you hand off
the telescope, can make the same observation. And then Newton comes along and comes up
with, you know, works with Kepler's ideas and creates this new, this new physics. Where the
universe runs, you know in the cliché, runs like clockwork, and then Einstein comes along and
modifies it.
This, if I'm correct and if the scientists who are working on this are correct, as I said in the
beginning, it's like we’re in 1610 all over again. There’s this revolution going on. We have every
reason to believe that these observations are valid. And we don't know what the outcome is
going to be. We don't know what the effects are going to be. What I want to do with this book
and in showing how these people, these rivalries, and how these people who are racing each
other throughout the 1990s, to make an observation, made the observation. They succeeded,
but they opened up this whole other, this whole other realm of what, what we don't know in the
universe. And they, and I also want to say that the scientists find this invigorating. They don't sit
there and go what have we done? We don't know the answer. The fact that they don't know the
answer, the fact that they came up with a result and then that opened up a bigger mystery is very
exciting. And I quote this in the book, there was a theorist at, at a conference that I went to and
he said, if you could put the whole timeline of the history of science in front of me, this is where I’d
want to be. And this is the sentiment that I hear again and again and again in the community.
The people are really excited by this, frustrated, but they're also really excited because they know
that this is something that is going to have these profound implications for centuries to come. We
just don't know what those implications are.
So part of the purpose, as I said at the beginning of my writing this book, is to just let people
know, people like yourselves, who know who have heard about dark matter and dark energy and
probably have some knowledge of it, put it into this broad historical context so that we can begin
to see that this revolution is taking place. And yea, we don't know what it means but, we know
that it's important. So I'll stop there and I'll ask for questions, if anybody has them, and if I have
any answers. Yes?
>>: I have very little technical knowledge in this area, but maybe you can help me interpret this.
It would seem to me that there are, there had to be a huge number of assumptions behind these
interpretations of the data like the thing about a galaxy like ours should have, you know, split
apart, and the fact that it didn't is evidence that there something else going on. How sound are all
the assumptions that suggest that there is an anomaly?
>> Richard Panek: Yea, good question. Obviously, scientists ask themselves the same
question. How sound are our assumptions? The, the analogy you could use is that while there's
an effect here, right? And they’re inferring from the effect. But it's similar to gravity. We don't
know what gravity is. But we know we can, we can come up with the equations that match our
observations. But we still don’t know what gravity is. That's part of the whole general relativity
quantum problem that we can't reconcile the two, and where a lot of it breaks down is in the realm
of gravity. I'm actually hoping that my next book will be on that subject, and even my editor
doesn't know that, so I'm talking with her next week.
But so it's, it's difficult to say, and it's slightly beyond my area of expertise, except that people are
used to thinking in this way and saying we know that there's an effect there, and we have to make
an inference based on that effect. Now it's always possible that Newton was wrong, and Einstein,
Einstein's modifications of Newton were wrong. And that all we need to do is modify gravity. And
people are working on that. And Vera Rubin, this astronomer I mentioned, the flat line galactic
rotation astronomer, I saw her over the weekend as well in Washington. And, you know, she's 82
and she made these extraordinary discoveries and they changed astronomy and they changed
cosmology, but she’s still sitting there saying, look, we haven't found the dark matter. Maybe,
maybe it is modified gravity, I don't know. But the observations of the cosmic microwave
background that I mentioned at the beginning, so closely match, you know, the, the computer
simulations, the simulations of the universe, that people are pretty confident that the inferences
that they've made, that you're talking about, and the assumptions, were valid, and got us this far.
But could things be wrong? Things are often wrong in science, and so, you know, you can't say it
with certainty, but with a high level of confidence I think. Thanks. Yes?
>>: Are there any assumptions about the nature of dark energy that distinguish it from the four
basic forces?
>> Richard Panek: I'm not sure exactly what you mean but because it's yeah, yeah.
>>: Nuclear force gravity [inaudible] and so on.
>> Richard Panek: I'm not hearing that. I'm not hearing that in the community. I'm not hearing
the need for another force. They’re more working with, on the theoretical level, you know, they're
willing to try anything. I mean, the observers are very frustrated, because -- you know, I saw this
one observer one, one of the discoverers of dark energy went to the leader of the astronomy
team at a conference in a room full of theorists. He said give us something to work with. You
know, we’re dying to go out make these observations, but you guys are not coming up with
theories that we can go and test. But you know, some of these theories are that there's a parallel
universe and it’s intersecting with ours and that's when we perceive gravity as an artifact of this,
this intersection of the two universes. But I don't hear, you know, so in that sense there's
questioning of the four forces that why is gravity so weak compared to the other three forces?
But I'm not hearing an indication of a fifth force. If that answers your question. Okay. Yeah, yes.
>>: In your conversations, what are the experiments that are being set up right now that
physicists are excited about for results in the next 10 years, that we should keep in the back of
our minds?
>> Richard Panek: Okay. There are several methods that have been developed in the last 10
years beyond the supernovae that I've been talking about. For dark energy, are you talking
about? Of dark matter? Okay. Well the dark matter experiment is one that I mentioned is, is I
think it’s in phase 2 or phase 3, I'm not sure but it's getting to the point where we’ll supposedly
have a result within the next decade. Large Hadron Collider, it's you know, it's a telescope of a
different sort, in that it re-creates conditions in the first moments of the universe and it's possible
that it'll spit out one of these candidate particles for dark matter. On the dark energy side, there is
as I started to say, these different methods. One is using gravitational lensing, which is where
you put a galaxy in front of another galaxy, and you can see the galaxy behind because the light
is distorted and you can re-create the galaxy. You could also use it to find out how much, how
much mass the foreground galaxy has. And you, then you can compare that with observations
and say, this is the mass we see, and this is the mass that must be there.
And again, if that dark matter issue, but you can also use that to map galaxies and how galaxies
are mapped over time. As we go back farther and farther away in the universe how the largescale structure of how galaxies, you know, in this kind of lattice, I don't know if you've ever seen
these, these re-creations of, of the universe on a very large-scale through observations like the
Sloan, the Sloan Digital Survey, where there are these, it kind of looks like a cobweb, so that
there are these, so that it's all fulminatory, that there are great gaps between the clusters as
they’re strung around,
and then there are these kind of low, you know, these kind of centers where everything is kind of
tightly packed. So those observations as you look back in this kind of, in this kind of, in this kind
of way, this is awesome. And then you look farther and farther back at this stretch of the sky and
as you're looking farther out you're looking farther back in time and you can see how the largescale structures changed over time. That will tell you how dark energy, how the expansion
changed the structure and evolution of the universe over time.
So those are going on. The South Pole telescope, which I went to visit, which is right at the
South Pole, which is very cool. Is looking at galaxy clusters using something called the sunyaev
zeldovich effect, which I don’t need to go into, but it uses the cosmic microwave background,
uses photons from the cosmic microwave background, how they they've changed in their journey
from there to us, by intervening galaxies to, again, map these clusters using a different
methodology, so that they can compare the two different methodologies.
Dark energy there's a decadal survey that the National Research Council publishes every 10
years, and last year dark energy was made the highest priority both in space and on the ground.
But the telescope which has been on and off the drawing board for 10 years is in tons of trouble
because the James Webb space telescope, which should've launched a couple of years ago and
is billions of dollars over budget, is still several years away from launching, and is still $1.6 billion
short of where it needs to be, is gobbling up all the resources and they can't begin that until, that
until James Webb launches, which is now the middle of the decade. Which means that, that
telescope wouldn’t be online until the middle of 2020s. So there's a lot of frustration in the
community about that. So those are the big ones that you can keep an eye on. Anybody else?
Yes?
>>: Sorry if I missed that in your…is there a relationship between antimatter and dark matter?
>> Richard Panek: This question came up, this is, this is beyond what I know, but this question
came up over the weekend at this talk I was giving where there was a dark matter and a dark
energy people present. And I'm not sure, but I seem to remember that the answer was no. But I
can't say that with certainty, and I'm sorry.
>>: Is the antimatter part of those 4%?
>> Richard Panek: Again, I’m just. This is the part where I get to say, I don't know. And beg your
indulgence. Thanks. Yes?
>>: So as a writer versus being a scientist, you're obviously talking to a lot of different scientists,
some of which will come down more philosophically maybe on one side, and think that there's this
anthropic principle of [inaudible] to find this finely tuned and other people that are maybe, you
know, looking at string theory and be-all and end-all stuff. From the people that you’ve spoken to,
do you, have you been able to maintain pure objectivity, or are you finding yourself going more in
one direction or another?
>> Richard Panek: Well in terms of the interpretation of what they're saying I try to, there is no
such thing as pure objectivity. As you know so, I concede that right away. I mean every time I
tell my writing students this, that every time you begin to write, no matter what it is, you're
choosing even if it's “the” at the beginning of the sentence, you're choosing from millions of
choices, and you’re making one choice and it’s a subjective choice. In terms of the anthropic
principle, I have two ways to answer that question. One, if you don't know what the anthropic
principle is, it's like why is the universe so finally tuned to life for us to be here that we can
actually observe it, that there is this 73%, 23% and 4% ratio that allows for the universe to survive
long enough for us to be here. It’s such an improbable, unlikely collection of physics that, you
know, why would it, why would it be there? Personally, I like the anthropic principle a lot because
what it says basically is that this idea of more is continuing. That Galileo goes out and sees more
planets or stars etc. Hubble sees more galaxies. We continue to see more galaxies. Now we
see that there are. You know, that there is matter and energy that we can't interact with through
our five senses in the way that we’ve normally been able to do with astronomy. So I don't see
any problem with there being other universes. In which case, and in fact according to quantum
theory, there should be other universes. If our universe comes out of a quantum fluctuation, you
know this idea that space isn’t empty. That there's always, there's these virtual particles popping
into existence and that would be the origin of what we think of as our universe, this kind of
quantum pop. And in fact, that would lead to this period of inflation which you might've heard
about, which is that the first fraction, fraction, fraction of a second, our universe, the universe
inflated at an extraordinary rate. If that happened once, theorists can't find a way to turn that off.
So there should be infinite inflation. I mean it should just be going and going and going. So that
all these other universes are popping into existence. And if they run the numbers maybe infinite
is a little strong, but there should be 10 to the 500 universes. And if there are 10 to the 500
universes, then ours just happens to be the one that has this collection of physics that allows us
to be here and ask the question. That's the anthropic principle. People take inflation very, very
seriously and it’s part of the model. Now it part of the standard model. I said earlier that
cosmology has gone from metaphysics to physics in the last quarter of a century, 30 years, 30,
40, 50 years. Inflation is now part of it, so that they say it's the lambda which refers to dark
energy, lambda, cold dark matter plus inflation model. So does that make, does that answer your
question?
>>: Yeah just wondered if you had a particular…
>> Richard Panek: Yeah. Well, you know. And as, I mentioned WMAP, and I saw people at the
beginning of the decade, like virulently anti-anthropic. And because of WMAP, because, because
WMAP seems to be impossible to have as far as we know without inflation, and once you have
inflation, you have this, you know, all these other universes popping into existence. I’m seeing
that people are now going over to the anthropic side, and kind of saying, we have to take it more
seriously, and we have to figure out, can it make observable prediction? And that's, that's the
challenge now, is how to take this idea and make it into science. Is there a question back there
somewhere? I thought I saw a hand, yea?
>> Kirsten Wiley: Last question if that's okay.
>>: If there are, you know, tens of thousands of other universes, who's to say there's not
somebody else sitting out there and wondering what all of dark matter in their universe is
[inaudible] unique?
>> Richard Panek: So you're saying the other universe would have dark matter as well?
>>: Although there could be some other human sitting in some other universe and looking at their
universe and saying, oh this is great. They created this just for us.
>> Richard Panek: Yeah, exactly. I mean it raises all these kind of profound questions I think.
And there are people who will argue that there has to be another universe that is identical to ours,
that there somebody else asking that question right now.
I guess we’re out of time, so thank you very much I appreciate it.
[applause].