For now we see through a glass, darkly.
(1 Cor. 13:12)
"The reports of my death," Mark Twain once wrote,
"Are greatly exaggerated." I quote
Mark Twain because of what you may have read.
(No, not about Mark Twain, we know he's dead.)
"The Big Bang theory's dead," it was reported
In 1991. 1 Some cheered, cavorted,
Grown men were heard to shout, "Bang, bang, you're dead!"
A well-known Christian columnist helped spread
The word: the Big Bang theory "has gone bust,"
Cal Thomas told his readers. 2 You can trust
They made a joyful noise unto the Lord.
Creationist response across the board
Was, "Hallelujah! No explosion! This
Means we've been right! It's all in Genesis!"
But later findings showed what all along
We've known: the Big Bang is alive and strong. 3
It never was near death--that was a hoax
From the beginning, put out by such folks
As Thomas. Why? To sort this matter out,
Let's start with what the Big Bang's all about.The theory says the universe began
With the explosion of what science can
Describe but vaguely as a hot, dense spot
Of matter/energy. 4 We don't know what
Existed prior to that. Throughout the past
The cosmos has expanded from the blast.
What evidence, you well may like to know,
First led us to this strange scenario
Of all evolving from a superspot?
Is this a theory that has really got
Predictive power, helping with solution
To questions about cosmic evolution,
To problems dealt with in the origin
And structure of this universe we're in?
(The study of such questions is what we
Refer to by the term "cosmology.")
You bet it has--as any theory should
If it's to be considered any good.
So let's see just how this hypothesis
Developed, what predictions came from this,
Then how it weathered its alleged demise.It first of all should come as no surprise
That ours is not a static cosmos. We
Know well from Newton's law of gravity
All bodies in the cosmos will attract
Each other. Shouldn't all by now in fact
Be clumped together? 5 Yes, they should, of course,
Unless there is some counteracting force
Or motion that keeps things apart. That's what
Had Einstein puzzled once. He said, "I've got
This theory I call relativity,
That deals with motion, light, and gravity
In neat equations by which space is curved
And four-dimensional. 6 But I'm unnerved,
My neat equations say that space must be
Expanding or contracting! What we see,
Though, is a static cosmos, stars that stray
Not much at all throughout the Milky Way."
(He didn't know about the galaxies
Beyond our Milky Way, so dim were these,
Though soon to be resolved by Edwin Hubble.)
"So what expands? My theory is in trouble!
I'll have to stick a term in my equations
To keep the cosmos static. Aggravations!"
Thus Einstein blew the opportunity
To make a bold prediction 7 (of course we
Have hindsight, that was 1917,
Things did look static on the cosmic scene):
He could have said, "The universe contracts,
Expands, or maybe oscillates!" The facts
Observed seemed different, though, and so instead
He figured in a constant that he said
Would keep the cosmos balanced as somehow
It seemed to be.But let's go forward now
To 1929. That year may be
The greatest ever in cosmology.
By that time Hubble, using what was then
Earth's largest telescope, had found stars in
Great groups beyond our own. And what he saw
in '29 is now called Hubble's law:
The galaxies or star groups all recede
Away from one another, with their speed
Proportional to distance. How did he
Discover this? There is a shift we see
In any moving light, the same effect
(It's called a Doppler shift) that we detect
In sound: a car horn's higher in its pitch
When it's approaching, while a car horn which
Is speeding off is lower. A light source
Will shift as well; it has no pitch, of course,
But color: thus a light approaching you
Has spectral lines that shift toward the blue
End of the spectrum; if a light instead
Is moving off, then it's toward the red
The lines will shift. And that's what Hubble saw,
All galaxies toward the red. With awe
He saw the universe expanding! (Though
Poor Einstein couldn't say "I told you so"
But kicked himself--he had rejected what
His own equations told him--that does not
Negate the fact that relativity
Predicted an expanding cosmos. He
Had but to readjust his calculations:
He took the constant out of his equations.) 8Now with this cosmological redshift
(As it is called), one needs no special gift
To see that if the galaxies are moving
Away from one another, they are proving
They once were closer. Go back far enough
In time and they'll be ever denser stuff,
Till squeezed into the spot from which they sprang,
So dense things must have started with--a bang!
Now isn't physics easy? All you do
To get the Big Bang theory is put two
And two together! Estimate the speed
And distances as galaxies recede,
And calculate as well the time it must
Have taken these star groups to form from dust
And gas clouds (although galaxy formation
Has been a subject of much speculation--
I'll talk about that later), and you'll know
How long the cosmos has been on the go.
It's been as long as fourteen billion years
By latest estimates.But what appears
To have exploded? First, don't think that we
Refer to an explosion where debris
From something gets blown into space. That's not
What we must picture, space itself is what
Expands: the blast was everywhere. 9 Okay,
But what got this expansion underway,
And what was there before? We do not know,
To put it simply. When we try to go
Back all the way, we find we can't get past
What's called the Planck time: we're stopped at the last
Instant before the blast itself, because
We do not know the physics, all known laws
Break down. 10 There's no way mathematically
To speak about the "singularity,"
The term used to denote that superspot
Where time reads zero: things are much too hot,
The density and curvature of space
Are infinite. We can't reach such a place,
Time's first split second has already run
When we get down to Planck time: that is one
Tenth of a thousandth of a millionth of
A billionth of, let's see, a trillionth of
A trillionth of a second following
The Big Bang 11 (as Fred Hoyle dubbed the thing
Back in the '40s). 12 That's as close as we
Can get. From Planck time, then, what would we see?
We'd see at once a great burst of inflation
(Were it not far too brief for contemplation)
As particles congeal from energy,
And four known basic forces--gravity,
Electromagnetism, and the pair
Called strong and weak--are separated where
One superforce had been; inflation through,
Expansion will proceed (still not into
The second second yet!) more leisurely;
The cosmic temperature will steadily
Decrease until atomic nuclei
(Protons and neutrons) coalesce, this by
The time the cosmos is three minutes old;
In half a million years it will be cold
Enough (three thousand K--still plenty warm!) 13
For the first atoms finally to form
(Electrons binding with the nuclei);
Decoupling from matter, photons fly
Through space: light shines. And atoms ever since
Have grouped together. 14Redshift evidence
Exists, then, for our theory. We see how
The Big Bang follows from expansion. Now
I want to tell of a prediction--not
As used by the Biologist, 15 that's what
Is better called postdiction 16 (she "predicts"
The distant past based on our present fix).
No, this prediction came some twenty years
Before what was predicted first appears,
And this is a prediction that was made
Based on the Big Bang. Almost no one paid
Attention when in 1948
Alpher and Herman said, "We postulate
That an explosion such as the Big Bang
Would create radiation that would hang
Around today, the 'echo' of it still
Should be detectable. This static will
Be in the form of microwaves, will come
From all directions, and it should be some
Five K in temperature." 17 Then ends the story
In 1965, Bell Laboratory:
There Penzias and Wilson are ecstatic
When they conclude that the persistent static
Picked up by their antenna has to be
That foretold echo, not at five but three
K (close!), from all directions. What elation!
Now called the cosmic background radiation,
It was a lucky find: it brought these guys
Not just some static but a Nobel Prize! 18
Now let me tell you something else about
The Big Bang. Years ago we figured out
The cosmos is three-quarters hydrogen,
One-quarter helium, just traces in
The cosmos of the other elements. 19
Is there a theory that predicts, makes sense
Of just this mix of elements? You bet!
According to the Big Bang, what you'd get
Is hydrogen three quarters, helium
The rest! (The other elements? They come
From stars, from the nucleosynthesis
The Astronomer spoke of.) 20 On top of this,
Earth's age supports the theory too. As I
Have said, the estimates now go as high
As fourteen billion years since cosmic birth;
The radiometric age found for the Earth
Is near five billion, which fits right into
The larger picture.Everything rings true,
It seems: redshift, the background radiation,
The elements, the time of Earth's creation,
And Albert Einstein's relativity
(A theory that's well tested as can be).
How is it, then, creationists made merry
And published a Big Bang obituary?
Well, first of all, the Big Bang is the same
As any other theory you can name
In that it doesn't give us answers to
All questions, something no Einstein can do.
Now here's the question that made rumors warm
Cal's cockles: how do large-scale structures form?
(What, you may ask, are "large-scale structures"? These
Are clusters, sheets, great gobs of galaxies.)
The cosmos, though it's not all seen by us,
Is on the large scale homogeneous--
At least we so assume, because we find
The background radiation left behind
By the Big Bang to be so smooth. 21 And that
Suggests the early universe was at
A high degree of smoothness. How can we
Explain, then, all the lumpiness we see
Today? It had us stumped. In recent years
Research by some of my distinguished peers--
I'll mention Margaret Geller--seemed to show
Galactic structures on a scale that's so
Humongous they posed quite a mystery; 22
They couldn't be the work of gravity
Alone, not in just fourteen billion years,
Not when the early universe appears
To have been so unlumpy. 23 Furthermore
These structures couldn't be accounted for
By "cold dark matter." That should be defined,
So I'll digress a moment. There's a kind
Of matter that's too dark for us to see;
We know it's there, effects of gravity
Reveal it--over nine-tenths of the mass
We know of can't be seen! (Now that's a class
Of mass we'd like to know much more about.
Black holes, where even light cannot get out;
Brown dwarfs, 24 which are failed stars [no starlight glows
Without nuclear fusion]; galactic halos;
And clouds of gas and dust, these all may be
Among the keys to this dark mystery.
Theoretical WIMPs--weakly interacting
Massive particles--may be impacting
The picture too: These particles may be
A lot, or all, of mass we wish to see.
Neutrinos have some mass, researchers say,
A find that also may come into play
In solving this dilemma.) 25 For a while
The cold dark matter theory was in style
("Cold" means the particles move slowly, "hot"
Dark particles move fast); but though a lot
Of us had thought it was the best solution
To the galactic structures' evolution,
The cold dark matter theory seemed to fail
In terms of structures on the largest scale.
So some said it was dead 26--and when they did,
Know-nothings then began to nail a lid
On the wrong coffin! What was "dead," you see,
Was just a theory about galaxy
Formation, not the Big Bang. (By the way,
The cold dark matter theory didn't stay
Dead long, the cosmic background radiation,
We'll see, helped bring about resuscitation.) 27
Newspapers ran headlines that so misled
The public, many folks thought they had read
About the Big Bang theory dying, not
A theory about large-scale structure. What
Cal wrote was nonsense!But then what to do
About the structure question? Let's review
Some data from the COBE satellite
(Cosmic Background Explorer), data right
From the explosion's afterglow. They show
That just three hundred thousand years or so
After the blast, the background radiation
Had ripples, many a tiny variation
In temperature--far less than one degree
In difference, and yet enough that we
Find here a clue to how large structures were
Then to evolve. For what do we infer
The ripples are? They're matter, it appears,
As it existed all those billion years
Ago, in varying densities. Around
This stuff more matter clumped together, bound
By gravity. These spots or ripples were
The "seeds," we think, of galaxies. (A stir
Was caused when Smoot, the COBE team's prestigious
Chief, said of the data, "If you're religious,
It's like seeing God.") 28But let's move on,
There's more we've learned. (Will all someday be known?
No, I don't claim we'll ever understand
Completely). Will the universe expand
Without an end (an "open" universe),
Its last stars burning out? Will it reverse
Itself as time goes on, with a "big crunch"
In store (a universe that's "closed")? Or scrunch
Up, then expand, in cycles? If it's flat
Instead of curved, with total matter at
"Critical density" (that's just enough
For gravity at length to stop the stuff),
Expansion will be halted--not, however,
Before it goes so long it goes forever
(If you can picture that). 29 If density
Is more than what we need for flatness, we
Are in for a big crunch; if it is less,
Then gravity can't stop us, we'll progress
(If that's the word) forever outward. We
Now think (thanks to a probe that lets us see
Those early ripples even better) that
There'll be no crunch: the universe is flat. 30
More matter, then, exists than what we see,
In cold dark form. Mysterious energy
Comprises what is left, for studies say
Expansion of the cosmos has someway
Been speeding up. So-called "dark energy"
Is thus proposed--it's antigravity.
That's why the constant that Einstein employed
To keep the cosmos balanced has enjoyed
A comeback--it's in this-and-that equation
To try to help explain acceleration. 31Exciting times! The Big Bang theory lives,
And will until such time as someone gives
A better explanation of the facts.
Creation? What does that explain? It lacks
Predictive power. Listen, I don't claim
That the Big Bang is gospel, it's my aim
To show it's still the best idea we've got
Based on what we observe. And it does not
Rule out creation. Could the Big Bang be
A firework set off by some He or She?
There's no way to confirm or to deny
That He or She was there. (I'll say that I
Would much prefer, though, that it be a She.
But I'm not chauvinistic, that's just me.)Paul Steinhardt has a theory that explains
The Big Bang as what happened when two branes
Collided ("branes" are short for membranes), that
There was no superspot but a Big Splat
Or a Big Bump instead. Won't say I doubt it,
So far I haven't wracked my brains about it. 32One last thing and I'll close. You may have heard
About this fellow Alan Guth. The word
That he put out is that the universe
Is a "free lunch," it came from "nothing." 33 Worse
Than that, creationists will say--they too
Promote creation out of nothing, 34 through
God's work--is Guth's and Linde's view that we
Live in but one of an infinity
Of universes, little bubbles, 35 and
Someday, says Guth, someone might understand
It all so well she'll have the tools--perverse
As it may sound--to start a universe
In her own basement. 36 Edward Tryon, there's
Another one: "Perhaps," Tryon declares
One day (it was a sudden inspiration),
"The cosmos is a vacuum fluctuation!" 37
What did he mean by that? Could there be truth
In this? Well, let me say that Linde, Guth,
And Tryon surely are not nuts or manics.
A branch of physics called quantum mechanics
Is weird indeed compared to everyday
Perceptions; but it helps us see the way
Things happen in the subatomic realm--
And I would say the devil's at the helm
If I were a creationist (they blame
The devil for about all you can name).
The quantum vacuum actually is full
Of particles that we call "virtual";
These particles appear and disappear
Through vacuum fluctuations. Thus we hear
It said that they come out of "nothing." Guys
Like Guth and Tryon then hypothesize
The universe itself began that way--
"One of those things," as Tryon likes to say,
"That happen from time to time." 38Tryon's funny
And Alan Guth has made a lot of money
(Guth first proposed inflation 39--not the sort
That keeps the rest of us all running short
Of money, but the rapid early stage
Of the expansion). Who, though, is so sage
That he can ever say, "I know"? Can we
Hope to unveil that singularity
We say exploded? It may in the end
Be more than we can ever comprehend.