Plain Talk with Brilliant Scholars

Welcome to Curioser and Curioser: Plain Talk with Brilliant
, yet another new weekly online feature for Each
Wednesday in this space, you can find interviews with noted
scholars on topics ranging from science to society, arts to
arithmetic. We’ll be going through the alphabet for the next six
months, starting with this week’s “A is for Astronomy.” So read on,
and let us know what questions and topics you’d like us to cover.
In this first edition of Curioser and Curioser, reporter
Martha Sadler contacted UCSB physics professor Robert “Ski”
. Her questions are both intentionally naïve
and conceptually deep, providing something interesting for both
astronomy no-nothings and experts alike. Said Sadler, “Some of the
professor’s answers are short and easy to grasp, while others might
require more study—but it’s all very interesting.” But before we get to the questions,
here’s what Ski had to say about participating: “Okay Martha, I’ll
try! These are of course deep questions. For some of them, science
has provided a very clear precise answer which has been tested
many, many times, and is essentially universally accepted by
scientists. For some of the questions, it’s not so clear. And for
one of them, we will probably NEVER know the answer with any
certainty.” And here we go: How did the universe begin? If
applicable, please explain how something came from
This will be my most frustrating answer. There
are ideas by people such as Steven Hawking about how “baby
universes” are created, but they remain speculative, to say the
least. I will say this, though: Just as the surface of a balloon is
finite, yet has no boundary, the spacetime making up our whole
universe may, according to present knowledge, also be finite yet
have no boundary, either in time or space! This is because
spacetime, in common with the surface of a balloon, has the
property of curvature. So asking what happened before the Big Bang
may be just like asking what is north of the North Pole!
Can you describe the model of the universe that is based on
ether? The idea is enjoying some vogue now. Is it at all
In a word, no. The ether idea was rejected
decisively a century or more in the past because of failed
predictions too numerous to mention. The idea behind the ether was
that light behaves in some ways like waves on the ocean, with
speeds and frequencies and wavelengths. Since water waves travel in
a medium (the water itself), it was thought that by analogy, there
must be smooth space-filling substance for the electromagnetic wave
(light) to travel in.

I’ve heard that some research astronomers at other
universities are currently entertaining the notion of ether, as
reported in last month’s National Geographic article
titled “Dark Mass’s Rival.” Ether seems to answer a lot of
questions, reducing pressure on the curious layperson to understand
Einstein’s general and special theories of relativity, black holes,
and string theory, as well as dark matter.
This article presents a completely new
and idiotic use of the word ether. These people have apparently
redefined the term in their minds to mean anything that fills all
of space. It’s just very unfortunate that they picked a word with
all of that historical baggage. I don’t think the scientists
working on this are confused about the usage, but for sure it
confuses the hell out of members of the public who are trying to
follow these things intelligently. However, I suppose it’s
semantics and people can say what they want. Remember this from
Through the Looking Glass? “When I use a word,” Humpty Dumpty
said, in a rather scornful tone, “it means just what I choose it to
mean—neither more nor less.” “The question is,” said Alice,
“whether you can make words mean so many different things.” “The
question is,” said Humpty Dumpty, “which is to be master. That’s
all.” Here ether is referring to some hypothetical substance that
might in principle invalidate the arguments for dark matter. The
idea is so hypothetical that it’s not worth considering except by a
few specialists. The chance that it is correct is miniscule, as the
proposer essentially acknowledges. That doesn’t mean it’s bad
science: People should always be coming up with wild ideas and
checking them out. But it’s completely nutty to bother the public
with them at this stage of development. There has been a gigantic
unexpected discovery that is totally worthy of everyone’s
attention. There is a newly discovered space-filling material that
has revolutionized our view of the universe, though it has nothing
to do with light propagation. It’s a million times more important
than the so-called “ether” discussed in the article. This discovery
has told us what the dominant component of matter is in the
universe—dark energy—and explained the observed flatness of space
overall. So what is dark energy? It’s been discovered over the last
decade that the expansion of the universe is speeding up. Since the
three forces in nature (electroweak, strong, and gravity) known in
1995 can’t explain an acceleration of universal expansion, is was
posited that perhaps there’s a previously unknown substance that
fills all space, and that one sample of the stuff repels other
samples of the stuff. This would cause the expansion to speed up,
just as an attractive force such as the usual gravitational force
would cause the expansion to slow down. It wouldn’t be crazy to
call it antigravity, but that term isn’t very well defined. Again,
in no way does this conflict with relativity. In fact there is a
mathematical place in Einstein’s equations for putting in a
repulsive force, should one ever be discovered, and the observed
acceleration may be a manifestation of such force. If we’re
stuck with relativity, can you just explain why space and time
can’t be two different things instead of spacetime? I prefer them
as two different things.
Let’s make an analogy with sound
waves. Sound waves comprise compressions and rarefactions
(thinning) of the air (or water, etc). It does need a medium in
which to exist, by its very definition. In a vacuum, there can be
no sounds at all. Suppose you are at the train station and you hear
the whistle of a stationary train blow in preparation for leaving
the station. You can use pressure sensors to measure the sound
wavelength. If the tone is middle C, each wave is about
four-feet-long. When a similar train approaches the station, the
waves are bunched up (this would be true of a water wave as well),
and we measure a shorter wavelength, say three feet. Now suppose
the train is stationary, and we are approaching it. The whistle
blows, and we measure the wavelength as the full four feet! The
crucial point is that, while in the second and third cases the
distance between train and listener is decreasing, in only the
second case is the measured sound wavelength shortened. That must
always be the case if a wave is propagating through a stationary
medium such as the air or (for light) an ether. But light simply
doesn’t behave that way. Whether the light source is moving towards
us, or vice-versa, you still get the compression in wavelength. In
fact, for that reason, it’s not possible to say whether it is the
train or the listener that is “really” moving based on this
experiment. You know how space goes on
forever and ever and ever and ever and ever? Do you think the
infinitude is infinitely filled with galaxies and the
We don’t know whether or not space goes on forever.
Do you know that when you look at the sun (don’t try this), you do
not see the sun as it is right now? Since it took about eight
minutes for the light (carrying the image of the Sun) to get to
Earth, we’re actually seeing the Sun as it was eight minutes
earlier! Of course, it probably doesn’t look much different now,
but this establishes the principle that when we look at distant
objects, we see the objects as they were back in time. There is
overwhelming evidence that the age of the universe is close to 14
billion years. I can’t explain it all here, but the first simple
and powerful clue was that all the galaxies are observed to be
separating from each other. So using the formula “distance = speed
times time,” we can calculate how long it’s taken for the galaxies
to get as far apart as they are today. The answer is 14 billion
years. If you look at an object so far away that the light we now
see actually left the object 13 billion years ago, we say that the
object is 13 billion light years away. We see the object as it was
13 billion years ago, and thus when the universe was only 1 billion
years old. We can study a certain signature of light left over from
the early history of the universe. It’s called the Cosmic Microwave
Backround. and its existence was predicted in advance with all the
exact right properties! We see this light as it was emitted when
the universe was only 300,000 years old. So we can see things as
they were closer and closer to the beginning of time. Now ask me
what the universe is like 50 billion light years away. Answer:
Don’t know! According to present understanding, the light from any
objects that far away simply hasn’t gotten here yet, so we can’t
see them, however big our telescopes! The maximum distance that we
can see due to the finite age of the universe is called the Cosmic
Horizon. The volume of space within the Cosmic Horizon is called
the Observable Universe. There are ideas about what lies beyond
that, or regarding the existence of alternate universes. They may
be true but I don’t think they can ever be tested decisively, so
I’m not too interested in them. Do phenomenon also get
infinitely small, such as worlds within worlds?
No one
knows this. So far it seems to be true. Maybe we’ll never be able
to answer the question, because whatever extremely small pieces of
matter that we do discover, I think it’s always possible that
they’re made of even smaller pieces. Do you suppose the
universe is comprised entirely of cause and effect chains, or is
there wiggle room for chance, divine intervention, or human
There is definitely, definitely room for chance, and
this has been proven many times! Suppose we have two atoms of
radioactive Uranium. These atoms are according to present, very
solid knowledge, exactly the same. Yet one will emit a radioactive
particle before the other, by chance!!! Is there a point at
which astronomy ceases to be intuitive, or at least analogous to
something we can sense?
Yes. Often in science it turns out
that a pattern in nature cannot be explained by an analogy to
something in everyday life, and some behavior in nature seems to
run counter to our intuition. Relativity and quantum mechanics are
two excellent examples. The reason is likely to be that our
intuition and common sense evolved for preferentially passing on
our genes on a planet with gravity is weak compared to that of a
black hole. On earth, where things generally move much slower than
a light beam and so many particles are involved, intuition about
the effects of quantum mechanics does not help us biologically.
At that point, what good does it do to study it?
Most of us would say that’s where it gets extremely interesting and
seductive. There are also many crucial technological applications.
For example, pilots and others often find their location to good
precision by receiving radio signals from the “Global Positioning
System” of satellites. For this to work, we need to know the exact
locations of the satellites at any given time. These positions can
only be predicted very precisely by using Einstein’s theory of
gravity, which includes the mixing of time and space, black holes,
etc. (Remember, theory does not mean hypothesis in science. We call
it Einstein’s “theory” of gravity even though all its predictions
have come true perfectly!) Thus, if Einstein’s theory weren’t
known, this positioning system wouldn’t work, and planes would
crash all the time. When do you think we will communicate
with creatures on other planets?
This one is way too hard.
I think we should at least try listening though. It’s not that
expensive compared to other things. There are efforts being made to
detect signals from intelligent extraterrestrial beings, though not
on this campus. See for example on the internet. If you
allow them to use your computer when you’re not using it, your
machine may be the one to find the extraterrestrials. This
particular research group was portrayed in the book and movie
Contact. The major characters in that story are
real people, although of course they haven’t yet found any
extraterrestrials. Do you think the terrestrial
distinction between plant and animal, or even animate and
inanimate, is universally applicable?
I sure don’t know.
Roughly speaking (biologists will cringe at this simplification),
plants get their energy from light, and animals get their energy
from chemicals (usually synthesized by plants using light energy).
I wouldn’t be too shocked if there were the same two general
categories on other planets. Is there any reason to think
extraterrestrial beings will resemble earthlings, or are they just
as likely to be spherical or incredibly small or large or
It is extremely likely that they will be
extremely different from us in their level of biological and
technological evolution. There is a wonderful explanation of this
in Carl Sagan’s book The Dragons of Eden. He says that to get a
feeling for the history of the universe, let’s pretend the whole
thing took just one year. On that scale, if the origin of the Big
Bang expansion was on January 1, then Sagan estimates that the
formation of the Earth would have taken place somewhere near the
middle of September. The first fossils come from organisms that
lived in October. The dinosaurs were around in late December.
Humans arrived at very roughly 1:30 p.m. on December 31. Neolithic
civilizations emerged on 11:59:35 p.m. on December 31. The
Renaissance in Europe occurred at 11:59:59 p.m. And just about on
the dot of New Year’s, we developed the technology to
self-destruct, and to start contemplating interstellar travel. His
point is, even if by some chance life evolves on another planet in
exactly same way as it does here, it would be impossibly unlikely
for it to be synchronized with life on Earth so closely that they
look the same and have the same technology. It is much, much more
likely that life on the other planet would be millions or billions
of years behind us or ahead of us. Is there anything you’d like to
Yes, I’d like to tell you my view on the
scientific method, which I don’t think is controversial. I simplify
it to two essential steps. 1) Development of a hypothesis based on
a collection of observational and experimental data. This step is
an example of inductive reasoning, dreaming up a general pattern or
equation based on study and contemplation of much experimental
information, often aided by what one might call intuition or even
genius. 2) The second step of the scientific method is deduction of
the consequences of the proposed formula, to see if it “pans out.”
For example, since all the predictions of quantum mechanics have
come true perfectly, this is the theory of greatest value in
understanding the universe, and in, say, reproducing recorded
music. Note that in science the word “theory” is used for a pattern
of behavior, no matter how solid the explanation may be. That’s
different from the usage in everyday life [which implies something
that is unproven]. In my opinion, all other belief systems
(astrology, religious creation myths, etc.) are based on the first
step, and the second step is simply neglected. In scientific
experimentation, we engage in a respectful dialogue with nature,
and we change our ideas when they lead to predictions which don’t
come true.

Keep the Conversation Alive

Learn more about Ski and his research by clicking here or
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