The REALLY Big Picture

We start from the fact that the Universe was created by God in 4004 BC.

Oops, not exactly. It was actually more like 13,800,000,000 BC (give or take a year or two). The event is called the Big Bang — a name given by astronomer Fred Hoyle intended sarcastically — and it was not an “explosion.” Rather, if you take the laws of physics and run the tape backwards, you get to a point where the Universe is virtually infinitely tiny, dense, and hot. A “singularity,” where the laws of physics break down — and we can’t go farther back to hypothesize what came before. Indeed, since Time began with the Big Bang, “before” has no meaning. Nevertheless, while some might say God did it, it’s reasonable instead to posit some natural phenomenon, a “quantum fluctuation” or what have you.

So after the Big Bang we started with what’s called the “Quantum Gravity Epoch.” It was rather brief as “epochs” go – lasting, to be exact, 10^-43 of a second. That’s 1 divided by the number 1 followed by 43 zeroes.

That was followed by the “Inflationary Epoch,” which also went fairly quick, ending when the Universe was still a youngster 10^-34 of a second old.

But in that span of time between 10^-43 and 10^-34 of a second, something big happened. You know how it is when you eat a rich dessert and virtually blow up in size? We don’t know what the Universe ate, but it did blow up, going from a size almost infinitely small to one almost infinitely large, in just that teensy fraction of a second; thus expanding way faster than the speed of light.

After that hectic start, things became more leisurely. It took another few hundred million years, at least, for the first stars to twinkle on.

This is the prevailing scientific model. If you find this story hard to believe, well, you can believe the Bible instead.

Here are some more facts to get your head around. Our galaxy comprises one or two hundred billion stars, and is around 100,000 light years across. A light year is the distance light travels in a year – about 6 trillion miles. And ours is actually a pipsqueak galaxy; at the bottom of the range which goes up to ten times bigger. And how many galaxies are there? Wait for it . . . two trillion. But that’s only in the observable part of the Universe; we can only see objects whose light could reach us within the 13.8 billion years the Universe has existed. Because of its expansion during that time, the observable part actually stretches 93 billion light years. We don’t know how much bigger the total Universe might be. Could be ten trillion light years across. (I don’t want to talk about “infinite.”)

Now, it was Hubble who in 1929 made the astounding discovery that some of the pinpoints of light we were seeing in the sky are not stars but other galaxies. And more, they are moving away from us; the farther away, the faster. Actually, it’s not that the galaxies are moving; rather, space itself is expanding. Jain analogized the galaxies to ants on the surface of a balloon. If you inflate it, the distance between ants grows, even while they themselves don’t move. And note, space is not expanding into anything. It is making more space as it goes along.

But there are two big mysteries. Newton posited that the force of gravity is proportional to mass and diminishes with the square of the distance between masses. However, what we see in other galaxies does not conform to this law; it’s as though there has to be more mass. We don’t yet know what that is; we call it “dark matter.” (There is an alternative theory, that Newton’s law of gravity doesn’t hold true at great distances, which might account for what we see with no “dark matter.”)

The other problem is that what we know of physics and gravity suggests that the Universe’s expansion should be slowing. But we have found that at a certain point during its history, the expansion accelerated, and continues to do so. This implies the existence of a force we can’t yet account for; we label it “dark energy.”

“Ordinary matter” (that we can detect) accounts for only 5% of the Universe. Another 24% is dark matter and 71% dark energy. (Remember that matter and energy are interchangeable. That’s how we get atom bombs.)

But, again, the story is a lot simpler if you choose instead to believe the Bible.

(This is my recap of a recent talk by Vivek Jain, SUNY Associate Professor of Physics, at the Capital District Humanist Society.)