I don’t know if you’ve been paying attention to physics
news, but physics world has been abuzz the last couple of days because scientists working at the South Pole released the results of an experiment
to measure light polarization in the background radiation that pervades the
universe:
The science is a little involved, but the short of it is
that this result is a strong argument in favor of the theory of Cosmic Inflation,
which has been steadily gaining support over the last few decades. One of the things I love about this theory
is that it gives a stunning twist to this passage from the Book of Moses:
Moses1: 4 And, behold, thou art my son; wherefore look, and
I will show thee the workmanship of mine hands; but not all, for my works are
without end, and also my words, for they never cease.
5 Wherefore, no man
can behold all my works, except he behold all my glory; and no man can behold
all my glory, and afterwards remain in the flesh on the earth.
…
9 And the presence of
God withdrew from Moses, that his glory was not upon Moses; and Moses was left
unto himself. And as he was left unto himself, he fell unto the earth.
10 And it came to
pass that it was for the space of many hours before Moses did again receive his
natural strength like unto man; and he said unto himself: Now, for this cause I
know that man is nothing, which thing I never had supposed.
First a little background:
Inflation is a theory proposed in 1980 to explain why the universe is so
homogeneous. Imagine an ice-cold,
shallow swimming pool with highly accurate temperature sensors placed every few inches. You dump a pot of hot water into the pool,
and just a few seconds later you take temperature readings and discover that
everywhere you measure, the temperature is exactly 37.0001 degrees with a
variation of just a few millionths of a degree.
That’s a crazy result. How did the heat spread out over such a
large area so perfectly so fast? This
is pretty much what astronomers see when they look out into space. Everywhere they look, the sky is filled with
light (radio waves) that is exactly the same temperature with very tiny
variations. It’s a mystery. How do we explain it?
So, a physicist named Alan Guth came up with a radical
proposal. The big bang theory already
suggested the universe was once incredibly tiny. Alan suggested that the early universe was
able to reach a common temperature quickly because it was so tiny, but it must
have gotten very big very fast in order to spread out the temperature evenly. People thought this was too crazy to be true
at first, but several predictions were made from this theory and every one that
has been tested has been experimentally verified (so far), and the latest
result of the past few days is a very strong confirmation of the theory.
Anyway, the term “inflation” is a rather innocuous word to
describe something that is truly mind-boggling and astonishing. The rate of this expansion would have been
enormously exponential. The theory says
that in 10-32 seconds, the universe expanded by 50 orders of
magnitude! That is such huge rate that
it is beyond any useful analogy to describe.
But just try to imagine it.
Imagine a tiny atom exploding into a ball the size of a galaxy in a
billionth of a second. Now multiply that
rate by a trillion trillion trillion.
That number would still be too small.
It is a flabbergastingly large number.
But I haven’t even gotten to the crazy part yet.
This inflating universe would have been extremely hot: 1022
degrees. Of course, it eventually cooled
down into what we can see now. We would
call this a “bubble” in the fiery hot expanding soup. When we look out at the sky and see all
those galaxies that stretch for billions of light years, we are looking at just
a portion of this bubble. What
we are able to see is defined by the age of the universe and the speed of light. Since light has a limited speed we can only
see the parts of the universe that have had enough time for the light to reach
us. The universe of galaxies, planets,
and stars is much, much larger than
what we can possibly see, because all of those objects are so far away that
their light hasn’t reached us yet. Based
on measurements of the cosmic background radiation, physicists have determined
a lower bound for this number: 196 Billion light years. The diameter of the volume that we can see
is 26 billion light years. That’s less
than 1% of the minimum size of that bubble I mentioned earlier- the minimum size - Some physicists think the bubble is millions
and millions of times larger than that minimum size.
But I still haven’t gotten to the crazy part.
In recent decades, Cosmic Inflation theory has pointed
in the direction of a concept called “Eternal Inflation”. The idea of this is that the rate of
inflation is much faster than the rate of cooling, so there is always a part of
the universe that is inflating, far beyond the cooled boundaries of the part we
live in. And remember, the rate of this
inflation is that huge unfathomable number!
Every second that passes, this inflating portion of the universe is
growing by that amazing rate. And in
that inflating portion, parts of it are condensing all the time into other
bubble universes like our own. The implication is that there would be a vast
number of isolated bubble universes, separated by a rapidly inflating see of
hot material that can make yet more universes at an exponentially increasing
rate.
I think of poor Moses, who probably thought the universe
consisted of the earth, and maybe a sphere of stars around it… if he went from
that to seeing the kind of universe that is coming into view now… no wonder he
fell over. It fills me with awe to
imagine that these are the works of God’s hands.
6 comments:
Thanks for such a great write up, Eric. I really enjoyed reading about it. I believe I understand it a tiny bit better. If the universe is expanding, I wonder what it is expanding into. What/when was there before the universe moved into the neighborhood?
So cool! As a scientist, how would you respond to the following points / questions?
1. It sounds like this is a clear admission that science has limitations on what can be known and/or deduced - e.g. if we can only see a small fraction of the universe, then science should be extremely careful about what & how it proposes ideas as facts?
2. Similarly, and I'm being slightly facetious here, if we are only able to "see" a small fraction of the universe, then a scientific search for God would be futile. Assuming He was visible to the natural, mortal eye, He could just simply hang out in the 99% of the universe we can't see.
Dave – thanks for the questions. Each one deserves a full post, but for now I’ll give some short answers:
1) Science does acknowledge its limitations, and it _is_ extremely careful about how it proposes new ideas and facts. ScienTISTS are another matter and they are often not careful. However, we can say categorically that when a scientist isn’t following the careful rules, then they aren’t doing science. In general, I don’t trust scientists when they don’t give equal press to their critics.
2) The problem with the 99% argument is that the people who say that God exists also insist that he is active in our lives, and therefore cannot be out in the 99% by their own argument. Therefore God is free game to scientists. Thousands of years of failed and unrepeatable experiments lead scientists to conclude that God not existing is the most likely answer to this problem. Science, by its own reasoning, cannot absolutely conclude the non-existence of something. Any scientist who tells you God cannot exist is either ignorant or dishonest.
Miles, to your first question, it is hard to imagine, but there is no notion of the universe expanding "into" something. Space is created by the exanding universe. (I don't really understand this either, but that is what the mathematicians say.) As for what came before, that is currently a topic of serious debate and inquiry. Some thing the big bang was the beginning, other think the universe has always been acting this way, and there are other ideas in between.
Hey Eric,
I liked your article. I've always thought that science only provides a simplistic explanation for what must be the infinitely complex and nuanced nature of God. Good science just reinforces my belief in our amazing creator. It makes me sad when people pit one against the other.
Jeremy
"In general, I don’t trust scientists when they don’t give equal press to their critics."
When your critics are people who believe in a man floating in the sky - which there is absolutely not one shred of proof of existence - then no, you don't deserve equal press.
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